Object

Representation ID: 5915

Received: 08/09/2021

Respondent: Mr Tom Tagg

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:
• General: No validation or calibration of the traffic model has been undertaken which is not in keeping with Department for Transport guidance.
• 2.4.2 Despite employment land being allocated in the BBC options, AECOM have assumed that no employment has been assumed to be associated with the proposed developments. This underestimates the journeys of employees and delivery vehicles to/from the sites.
• 2.4.3 AECOM have not applied site-specific trip rates but have adopted trip rates using a DfT model (CTripEnd). This results in “around 20 to 25 outbound car vehicle trips in the AM peak hour,”. The Colworth and Twinwoods development scenario options range between 2,500 and 10,440 houses. With a likely 2 cars per household, i.e. up to 20,880 cars, allowing only 20-25 cars is clearly a gross underestimate of the number of outbound car vehicle trips in the AM peak.
Given these, all of the assessments undertaken by AECOM to determine the rerouting, vehicle km travelled, junction delays and junction-capacity ratios for any scenario are highly unlikely to be representative.
4.5.21 and tables 3.15, 3.16, show that in the reference case (2030) 3 of the 4 arms of the Clapham Road/Manton Lane junction are at (100%) or above (104%) full capacity leading to significant delays. It should be much better highlighted that this is before any new Local Plan 2040 developments are considered in the model. This is therefore a BBC problem that arises from the developments allocated in the current 2030 Plan (even including the planned highways mitigations to 2030) that needs resolving independently of the Local 2040 plan. When added to the 2030 model the Twinwoods development only has a marginal impact on these junction capacity ratios, increasing these by a maximum of 3% to 107% of capacity.
4.5.22 Confirms that no mitigation has been proposed for the congestion at this junction – due to physical constraints of buildings and schools. This is unacceptable, as it effectively means that the brownfield site of Twinwoods is not therefore considered as a site for development.
4.2.9 Concludes that without a solution to the congestion and delays at the Clapham Road/Manton Lane junction, delivery of growth along the A6 corridor will be constrained. BBC need to find a solution to this – BBC are content to demolish houses to bring EWR to Midland road – maybe similar extreme action is required in this case to open up development in the north of the borough.