Changes to the PRISM Mode-destination Model Parameters
James Fox, RAND Europe
PRISM (Policy Responsive Integrated Strategy Model) in a large-scale transport model that is used to assess the impact of transport policy across the West Midlands region of the UK. It has recently been updated to reflect travel behaviour in 2011.
PRISM (Policy Responsive Integrated Strategy Model) in a large-scale transport model that is used to assess the impact of transport policy across the West Midlands region of the UK. PRISM has been developed on behalf of the seven local authorities that comprise the West Midlands metropolitan county and the UK Highways Agency.
The PRISM model has recently been updated to reflect travel behaviour in 2011. The new versionof the PRISM incorporates a number of improvements to the individual model specifications, specifically improved treatments of escort, employer’s business and non-home-based travel. Nonetheless there is sufficient similarity between the old and new versions to allow comparison of the mode-destination model parameters in the 2001 base version of the model with the new 2011 base version of the model.
This comparison will enable investigation of the stability of travel behaviour between 2001 and 2011. Analysis will be presented, for a number of different travel purposes, that investigates parameter stability for different groups of model terms, specifically:
• sensitivity to cost (after adjusting for real growth in incomes);
• sensitivity to travel time, and for public transport out-of-vehicle times;
• socio-economic parameters, including car availability, age, adult status and gender terms;
• parameters indicating the relative sensitivity of mode and destination choices; and
• mode and destination constants.
Comparing the results for different travel purposes will provide insight into whether the models for some travel purposes are more transferable than others, for example it may be that commute models which relate to a journey made frequently, usually to the same location, are more transferable than models for discretionary travel such as shopping.
The paper will also include a review of relevant papers from the model transferability literature, setting the results from this study in the context of findings from other work.
Association for European Transport