The Potential for Substitution Between Car and Public Transport: Looking Back After 20 Years
A Baanders, Ecorys, NL; T van der Hoorn, NL Ministry of Infrastructure and the Environment & University of Amsterdam, NL; J van der Waard, NL Ministry of Infrastructure and the Environment, NL
Review of a discussion on the substitution between car and public transport held 20 years ago. Do the arguments still hold? How will they develop in the future?
The issue discussed in this paper originated some 20 years ago (in 1988-1990) when in the Netherlands a national transport master plan, known as SVV II, was being prepared. In the face of the strong growth of car use at the time, one of the proposals was for a major expansion of public transport, in order to obtain a sizeable shift from car to public transport. However, the national transport model (NMS), which was used to make forecasts of intended policies, predicted that up to 2010 this would lead to an increase of public transport patronage, but not to a shift away from the car. This was a deception for the policy makers involved. Did it mean that the NMS model was wrong?
The authors, employed at the time at the then Dutch Ministry of Transport, produced some papers showing that (i) this model result was plausible, (ii) other research showed that private and public transport cannot be considered as communicating vessels, and (iii) the possibilities for substitution between the two are limited to a number of specific situations.
Using the results of the ex ante and ex post studies available at the time, we argued that the amount of substitution of trips from car to public transport as an effect of policy measures will differ strongly according to purpose, origin, destination and distance, because the availability and relative quality of public transport differs between market segments. Surely, substitution is to be expected in some transport market segments, but as these segments are relatively small, the overall effect will be limited. A substantial shift is only to be expected in specific situations.
Eventually, the proposed policy was scaled down.
Looking back 20 years later, this paper proposes to revisit the arguments we used at the time and see if they still hold. To what degree are private and public transport communicating vessels now? What are the factors that limited or promoted substitution between the two? What are the developments in the relative quality and availability of the car and public transport which we did not foresee? And what worked as we expected?
The paper will conclude that the main findings from 20 years ago still hold. Next, looking ahead 20 years, the paper will consider the likeliness that these factors will continue to work in the future.
Association for European Transport