Substitution of travel demand between car and public transport : a challenge to policy makers

This paper deals with the issue of substitution of travel demand between car and public transport. The emphasis is on two questions. Why do improvements of the public transport system attract so few car users, at least at a national scale? Why do so few car users switch to public transport in response to so called 'push' measures? The answers to these questions follow from many empirical studies in the Netherlands and abroad and amount to one common aspect: there are still too many spatial relations where the public transport supply is not a competitive alternative neither with respect to time, place or character among all the available alternatives for travel behaviour open to car users. This leads to the implication that if substitution of travel demand between car and public transport is to be the main objective of improvements in the public transport system, these should be aimed at (future) car users. Such an approach asks for public transport systems satisfying new design principles, with specific emphasis on elements which are perhaps less relevant to the present (mostly captive) public transport users.