This report documents a number of pre-existing traffic models and data sources that were considered for use in this review. It details how they were incorporated into the existing traffic model covering the M25 maintained by the Highways Agency, resulting in the new Lower Thames Crossing model that has been used to generate traffic forecasts associated with a new crossing at each of the locations under consideration.
The report also considers how the traffic model performs in the 2009 base year. It compares modelled traffic flows with observed data, and how sensitive the model is to changes in input assumptions. The report then compares the results with empirical data and the DfT’s WebTAG guidance and makes conclusions about the suitability of the model for use in the strategic assessment of additional Lower Thames crossing capacity