Transport policy appraisal with equilibrium models III: Investment benefits in multi-modal systems

We extend the analysis of papers I and II to explore theoretically and numerically within a multi-modal equilibrium framework the contributions of different response mechanisms to the benefit derived from highway and public transport investments. These include on the demand side modal substitution and other generative effects, and on the supply side the longer term responses by public transport operators to the patronage loss arising from highway projects. In the latter context we examine the significance of potential disbenefits to public transport users and comment on a recent debate about the possibility that building major roads in congested urban areas may be counter-productive.