Modelling Delays on Trunk Roads
In an earlier contract the Highways Agency commissioned Risk Solutions to develop a prototype Network Performance Model that could quantify the impact of changing traffic patterns on the Agency’s PSA target for journey time reliability for a small number of routes.
A limitation of this initial prototype was an inability to take account of the increasing probability of flow breakdown and potential queue lengthening as traffic demand increases. This is because of a lack of any suitable existing theoretical approaches to modelling these problems.
The Agency has now asked us to investigate possible ways of addressing these limitations. This is a very complex modelling challenge; if successful, the Agency wants to use the model to analyse the effect of projected changes in traffic flows on performance against the PSA measure for journey time reliability for the whole network. The Agency also wants to use the model to perform ‘What If?’ analysis of different traffic management options, including: