Comment
Draft Local Plan
Representation ID: 15827
Received: 11/05/2016
Respondent: National Highways
As there is no validated traffic model for Brentwood, PBA have adopted an alternative approach using available information. OmniTRANS has been used to build a simplified model of Brentwood Borough. The defined zoning system and an Integrated Transport Network (ITN) layer were imported. Additional zones were created to represent the proposed areas for major development sites. The mean link speeds from TrafficMaster (including junction delays) were added to the links. This model allowed skim times and distances to be calculated for each zone pair. A base year assignment was undertaken on the basis of census data and a synthetic distribution based on the trip lengths and the relative attractiveness (land use) of various zones. This was judged to be approximately correct but did not undergo any formal validation process. These time and distance skims were used to determine the distribution of development trips and also the assignment of those trips. In all of the assessed scenarios, the total level of trip growth resulting from planned developments was greater than the growth implied by TEMPro. Hence, there was no requirement to allow for additional developments. Indeed, the overall growth assessed was higher than that implied by national forecasts. he assigned turning movements of the development traffic at the assessed junctions were added to the observed turning movements To calculate future year scenarios. Hence, the future year assessments were not reliant on the base year assigned traffic flows.
See attached