Disaggregate Inter-Urban Mode Choice Models: A review of British Evidence with special Reference to Cross Elasticities.

The research reported in this paper forms part of EPSRC project GRK52522 entitled 'National Multi-Modal Travel Forecasts'. The principal aim of this project is to develop a set of national and regional travel demand forecasts by land-based modes. These demand models for car, bus and rail will be based on a hierarchy of techniques and hence there are several strands to this research. One aspect of the research involves the review of aggregate models, based on collective travel behaviour, and the evidence that they yield on own and cross elasticities. Whilst such models provide a wealth of information on own elasticities, and are particularly well suited to the analysis of the effects of exogenous factors on travel demand, they tend to make little allowance for competitive effects and hence provide little evidence regarding cross-elasticities. Furthermore, their nature is such that there can be only limited segmentation of the elasticities by relevant travel and socio-economic factors.

Another aspect of the study is reviewing the evidence that is provided by disaggregate models where, in contrast to the aggregate models, the unit of observation is the individual decision maker. Since such models examine competition between modes, they are particularly useful in providing evidence on cross-elasticities.

A further aspect of the work will be the actual estimation of relevant demand models and elasticities for a range of circumstances and by a variety of means.

The final stage prior to application of the models is to draw all the evidence together in a consistent manner, drawing upon the strengths of different approaches and the various insights that they provide.