Concessionary Travel, Car Ownership and Demographic Change
POLAK J and HAN X-L, Centre for Transport Studies, Imperial College, UK
Under the concessionary travel arrangements operating in London and many other large cities in the UK, particular social groups (e.g., the elderly and the disabled) are offered free or discounted fares on public transport services and participating public
Under the concessionary travel arrangements operating in London and many other large cities in the UK, particular social groups (e.g., the elderly and the disabled) are offered free or discounted fares on public transport services and participating public operators are reimbursed for the loss of revenue due to the discounts. However, operators are entitled to compensation only for that element of the lost revenue associated with the trips that would have been made at the nominal prevailing fare - they are not entitled to revenue compensation for trips generated by the discounts. Thus in the construction of frameworks for reimbursement, considerable interest is focused on the elasticity of demand for public transport travel by the target groups.
In the context of London, where concessionary travellers have free travel, the estimation of appropriate demand elasticities poses considerable challenges. At present the elasticities used are based on aggregate time series models of the total public transport market. In this paper we present an alternative approach, based on disaggregate data from repeated cross sectional travel diary surveys. This approach enables a much finer discrimination of target groups and more detailed investigation of the impact of socio-demographic factors. In particular, we use the new models to investigate the effect of increasing car ownership amongst elderly travellers on both the level and the elasticity of public transport demand.
The structure of the paper is as follows. In the first section we briefly review the existing literature on the modelling of concessionary travel, identifying the strengths and weaknesses of alternative approaches. The second section discusses the existing evidence on the effects of car ownership and other socio-demographic factors on concessionary travel. The third section outlines a new modelling approach, which is based on fitting Poisson regression models to disaggregate trip data from several waves of the London Transport Household Survey. The fourth section presents the empirical results and discusses their implications for policy. The final section presents some overall conclusions from the research and identifies future directions in terms both of data needs and modelling approaches.
Association for European Transport