3.25

Object

Representation ID: 4119

Received: 30/08/2021

Respondent: Mr paul giles

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 4168

Received: 30/08/2021

Respondent: Mrs MARGARET TURNER

The transport model used by AECOM is fundamentally flawed because the model has not been
validated/ calibrated (particularly with respect to public transport), a strategic model has been used
incorrectly and the data has not been tested. AECOM have significantly undervalued the number of
vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a
significant reduction in car use. If a new settlement is required it should
be at Little Barford. Alternatively Twinwoods with a guided busway or parkway
station.

Object

Representation ID: 4486

Received: 31/08/2021

Respondent: Mrs Lucy Crawford

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 4554

Received: 01/09/2021

Respondent: Mrs Kathryn Smith

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a
significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Another alternative would be Twinwoods with a guided busway or parkway station

Object

Representation ID: 4657

Received: 01/09/2021

Respondent: Mr Melvyn Chase

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 4704

Received: 01/09/2021

Respondent: Mrs Gerardine Meola

The proposed new settlement on land west of Wyboston is too far from proposed EWR station at Little Barford to reduce car use - even with a cycleway.

If there must be a new settlement it should be at Little Barford which will reduce car use.

The models have not taken into account the nature of open countryside roads (high hedges, single track, no verge, rutted verge and no paths) which would have an impact on access north from development on land west of Wyboston. The models only looked at vehicle movements - numbers which seemed low.

Object

Representation ID: 4710

Received: 01/09/2021

Respondent: Mr Joshua Zwetsloot

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.
As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document. (para 2.4.3 of document inserted here).
It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 4893

Received: 02/09/2021

Respondent: Ms Tara Skey

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore I believe that if a new settlement is required it should be at Little Barford. My second choice would be Twinwoods with a guided busway or parkway station

Object

Representation ID: 5168

Received: 03/09/2021

Respondent: Mr Chris Giles

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.



Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.

No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.

It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.

TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.

For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.






It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.

The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.

The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.

Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.

If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 5322

Received: 03/09/2021

Respondent: Mr Jetinder Dhaliwal

Will the further work to the spatial strategy be made available to the public for review ? Will the infrastructure delivery report be also consulted upon ?

Object

Representation ID: 5503

Received: 06/09/2021

Respondent: Mr Stuart Ledwich

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

Object

Representation ID: 5600

Received: 06/09/2021

Respondent: Mrs Julie Kilby

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 5651

Received: 07/09/2021

Respondent: Mr Phillip Yockney

The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 5702

Received: 07/09/2021

Respondent: Miss amber scally

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 5765

Received: 07/09/2021

Respondent: Miss Hannah Hambleton-Jewell

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 5801

Received: 07/09/2021

Respondent: Mrs Gillian Tagg

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. I also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the reasons stated in my responses to 1.23 to 1.27.
100-word Summary
The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore, I believe that if a new settlement is required it should be at Little Barford. My second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 5862

Received: 08/09/2021

Respondent: Mr Norman Hoy

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.
As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document. (Extract inserted here.)
It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

100 word summary
The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 5940

Received: 08/09/2021

Respondent: Mr Tom Tagg

Please refer to my responses 1.23 to 1.27.
The current transport modelling is FUNDAMENTALLY FLAWED as it has not been validated; does not allow for vehicles from employment; totally underestimates the traffic arising from major new settlements in the AM peak hour and therefore their impact on the network and resulting infrastructure improvements required. In addition, the conclusions to rule out developments to the north of Bedford on the A6 due to the congestion at the Clapham Road/Manton Lane Junction, have been incorrectly drawn.

Please refer to my response to 3.2.
With the excessive housing requirement set by the standard method, BBC need to mitigate this with the contingencies that they currently hold. Specific examples are:
• Windfall sites; The Small Sites Topic Paper demonstrates that for the last 5 years BBC easily meets it’s 10% housing requirement on small sites by windfall development. Windfall development is held as a contingency outside the current plan allocation. In the face of the excessive standard method demands, BBC should include windfall development of 10% within the additional 12,500 dwellings needed thus reducing this figure by approx. 1,250 houses.
• The Small Sites Topic Paper demonstrates an expected excess of small sites over the 10% requirement to 2040 of 920 houses. This should also be used to reduce the 12,500 figure.

Object

Representation ID: 5984

Received: 08/09/2021

Respondent: Staploe Parish Council

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.

TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.
As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.[Extract inserted here.]
It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.

The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.

The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.

Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.

If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.
100 word summary
The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 6031

Received: 08/09/2021

Respondent: Mrs Christina Farmer

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6121

Received: 09/09/2021

Respondent: Jen Giles

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.



Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.

No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.

It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.

TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.

For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.






It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.

The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.

The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.

Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.

If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6175

Received: 09/09/2021

Respondent: Mrs Sandie Tusting

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

Object

Representation ID: 6221

Received: 09/09/2021

Respondent: Peter Coles

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6322

Received: 10/09/2021

Respondent: Mr Paul Zwetsloot

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.


pg. 23 of 25

Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.

No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.

It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.

TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.

For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing). Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport
frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.




pg. 24 of 25

It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.

The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.

The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.

Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.

If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.

If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6450

Received: 13/09/2021

Respondent: Ms Donna Thompson

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.
[PARAGRAPH 2.4.3 OF NEW SETTLEMENT WEST OF WYBOSTON DOCUMENT]
It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Support

Representation ID: 6469

Received: 13/09/2021

Respondent: Mr Steven Kent

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
pg. 30 of 23
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.
As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.

It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6552

Received: 13/09/2021

Respondent: Mrs Susan Trolley

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
Staploe Parish Council do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6608

Received: 14/09/2021

Respondent: Mr Aiden Farmer

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document. [Para 2.4.3 extract inserted.]
It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.


3.25 100 word summary
The transport model used by AECOM is fundamentally flawed because the model has not been validated / calibrated (particularly with respect to public transport), a strategic model has been used incorrectly and the data has not been tested. AECOM have significantly undervalued the number of vehicle trips. Dennybrook is too far from the proposed new E-W rail station to cause such a significant reduction in car use. Therefore we believe that if a new settlement is required it should be at Little Barford. Our second choice would be Twinwoods with a guided busway or parkway station.

Object

Representation ID: 6730

Received: 14/09/2021

Respondent: Mrs Elizabeth Froude

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.

Object

Representation ID: 6768

Received: 14/09/2021

Respondent: Ms S Kelly

Infrastructure items are already identified within the adopted Local Plan, principally at policy 90S. What is critical is the timing for delivery of necessary infrastructure to support the adopted Local Plan and draft Local Plan going forward. If there is a transport corridor approach to growth then additional junction improvements may be required, and priority bus routes that interconnect with existing and proposed rail stations, including the East West rail station to the south of St Neots. We also believe that it is important to improve the A6 to the north of Bedford to enable those in the north of the Borough to access the town centre and the new East West rail station.
I do not believe that the transport modelling was adequate. The Transport Modelling undertaken by AECOM in support of the strategic options in the Draft Local Plan 2040 is fundamentally flawed for the following reasons.
No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport WebTAG guidance.
It is assumed that the Bedford Borough Transport Model was undertaken using Saturn, which was the model of choice for the Bedford Town Centre modelling project in 2015. In this case, Saturn cannot directly Model Public Transport therefore it is assumed that the engineers have made some significant assumptions with respect to public transport and trips being used, which have not been validated or calibrated.
TAG unit M1.2 introduces the National Trip End Model (NTEM). It includes forecasts of population, households, workforce and jobs over 30 years which are used in a series of models that forecast population, employment, car ownership, trip ends and traffic growth by Middle Layer Super Output Area (MSOA). The NTEM data set can be viewed using the TEMPro (Trip End Model Presentation Program) software. TEMPro estimates of trip ends at any level below aggregate regions (e.g. MSOA, district, or county level) are subject to uncertainty and should not be used as constraints in matrix development process without verification and possible adjustments. No uncertainty log was prepared which is a recommendation of WebTAG modelling guidance.
For direct use in matrix development, trip rate information estimated from household survey data should be considered instead to underpin trip end estimates at zone level. There is a risk that model may not be realistic or sensible due to the error around the model parameters used, or limitations in the extent to which the model can represent human behaviour. Therefore, before using any mathematical model, it is essential to check that it produces credible outputs consistent with observed behaviour. This is usually done by running the model for the base year (either the current year or a recent year), and:
• comparing its outputs with independent data (validation);
• checking that its response to changes in inputs is realistic, based on results from independent evidence (realism testing); and
• checking that the model responds appropriately to all its main inputs (sensitivity testing).
Five types of data can be collected and used to inform most models:
• data on the transport network, including the physical layout, number of lanes, signal timings, public transport frequencies and capacities;
• counts of vehicles or persons on transport services, links or at junctions;
• journey times;
• queue lengths at busy junctions;
• interview surveys, in which transport users are asked to describe trips either through household travel diaries or intercept surveys (e.g. roadside interviews, public transport onboard interview surveys.
These types of checks have not been undertaken to validate / calibrate the model.
AECOM have derived trip ends using CTripEnds for a number of journey purposes. Expanding synthetic trip ends produced by CTripEnd to the local zoning system is considered to be subject to significant discrepancies from observed especially if validation and the calibration exercise has not been undertaken.
It is also important to note that strategic models are not designed for use in a scheme specific assessment. For such an assessment it is recommended a revised forecast model would be produced from a recalibrated base year model using additional and more recent data and targeted to reflect a more specific geographical focus of resources and modelling effort.

As part of the Bedford Borough Transport Model documents it is quoted that average departing trips are 20 to 25 vehicles, which may be below the trip rates assumed as part of a detailed development assessment. The extract below is taken from the New Settlement West of Wyboston document.



It is unknown what scenario of Dennybrook (site 977) development that the above “20 to 25 outbound car vehicle trips in the AM peak hour” relate to, however an outbound TRCS residential trip rate is somewhere between 0.23 to 0.33 vehicles per dwelling.
The development scenario ranges from 2,500 dwellings to 10,150 dwellings. On this basis and using a 0.25 departure trip rate results in 625 to 2,538 departing trips all of which would be home based departure trips. The model assumes 5 loading zones which therefore means there could be 125 to 508 vehicles per loading zone. This is significantly higher than the 20 to 25 outbound vehicle used by the AECOM model, assuming they have loaded it per node.
AECOM may claim that some of the departing trips will be internal and therefore will not cross cordon line however taking the 125 departing vehicle trips associated with 2,500 dwellings scenario; 20% of these departing vehicles are considered not to be leaving the area. This percentage decreases further if the worst case number of dwellings is being considered, i.e. 10,150 dwellings. It has previously been highlighted that the AECOM model has not be validated / calibrated and now given the apparent significant under valuation of the likely vehicle trips that will be generated, it is clear that the assessment of the capacity of junctions and the highway network is fundamentally flawed.
The significant undervaluation of generated vehicle trips could be argued by AECOM as being a reduction due to the impact of the public transport. However, the proposed new railway stations associated with the East West Rail Link are located to the east of the A1, which is significantly far enough away for the Dennybook development to be considered to not directly serve it without requiring a vehicle car trip to be generated. In this scenario it more likely that occupiers of Dennybrook (site 977) dwellings will continue their journey by car as opposed to transferring onto rail.
Given this all of the assessments undertaken by AECOM to determine the rerouting and vehicle km travelled for any scenario are highly unlikely to be representative.
Town planning principles are that new development should be centred on and around existing sustainable urban area where local infrastructure exists and allow residents to travel using public transport to serve the development which can be easily extended.
If larger new settlements are the only realistic option then they should be centre on transport hubs such as a new railway stations so that they become the heart of the community and the de facto mode of travel. Locating a new settlement on the edge of town / out of town where the transport hub is also not well connected leads to a disjointed sustainable public transport which will always be second best to car travel.
If Little Barford is deemed unsuitable our second preferred option would be a new settlement of 2,500 homes at Twinwoods or Colworth. The Parish Council believe that the problems on the A6 north of Bedford are going to need to be resolved anyway in order to support the housing development proposed in the 2030 plan and for residents to access the east west rail station in the centre of the town. We believe that development of a new settlement of up to 3,000 homes at Twinwoods (site 883) or Colworth (site 1002) could provide the infrastructure funding to support improvements to the A6 which have long been needed and provide residents with access to the east west rail station in Bedford. A northern parkway station could be considered in future to provide sustainable transport for those in the north of the Borough. Twinwoods would include a significant proportion of brownfield land and Colworth includes lower quality (grade 3) agricultural land and so would comply with the NPPF requirement to utilise brownfield land or lower quality agricultural land before high quality agricultural land. These sites would also support Bedford Town Centre. Colworth was the site supported in the 2035 plan which was later reviewed. The A6 was not a considered sufficiently problematic to prevent this site being adopted so we find it hard to understand why the A6 is deemed such an insurmountable problem now.