The Value of Reductions in Rail Overcrowding: a Stated Strength-of-preference Investigation.
G Whelan, J Crocket, C Pownall, J Segal, L Hunt, MVA Consultancy, UK
The paper reports an investigation into the relationship between the willingness-to-pay for reductions to rail overcrowding and the level and duration of crowding. The analysis is based on a large scale stated strength-of-preference survey.
Overcrowding is becoming an increasingly important issue for the UK rail industry. The demand for passenger rail travel is at a 50 year high and is growing at a rate of 4.5% per annum. In many cases, the network is at, or close to, capacity and there is limited scope to price-off demand as principal commuter fares are regulated. The UK Department for Transport (DfT) is responsible for both rail industry strategy and for the specification of franchises; strategies for managing demand and capacity are integral to both of these. To be able to demonstrate value for money, it is essential for the DfT to have robust estimates of both the economic value of reducing overcrowding and the demand effects of it.
Evidence on the valuation of overcrowding contained within the rail sectors Passenger Demand Forecasting Handbook (PDFH) has a number of limitations. Existing values only extend to a certain level of crowding which is already exceeded in a number of situations, and without mitigating action, will be exceeded in many others in the future. In addition, the level of disaggregation, particularly in terms of geographical coverage, may not be sufficient to accurately reflect both current and future situations. The DfT has therefore commissioned this study to obtain robust estimates of the valuation of overcrowding across the range of contexts in which it may occur, so that it can take appropriate decisions on policies to mitigate overcrowding and demonstrate value for money.
The methodological approach adopted in this research is based on a large scale programme of market research including a series of six focus groups, 50 in-depth cognitive interviews, and the distribution of more than 10,000 web and paper based questionnaires across 14 sites aimed at collecting transfer price (TP), revealed preference (RP) and stated strength-of-preference (SSOP) data.
In this paper, we provide a description of the development and analysis of the stated strength-of-preference survey (further details of the transfer price and revealed preference approaches are recorded in a companion paper submitted to the rail stream of the Conference). An important aspect of the study was to undertake a qualitative investigation of how rail users consider overcrowding, how they change their behaviour to mitigate its effects, and how to describe/ present different levels of crowding as show material in the questionnaire. This investigation helped shape the specification of the strength-of-preference experiments and overall questionnaire design.
The questionnaire returns were analysed under choice modelling framework involving the estimation of a range of advanced models including multinomial logit, ordered logit, mixed logit and latent class models. The focus of model estimation was to examine how the value of travel time savings for rail users is influenced by both the duration and level of overcrowding, and how these (non-linear) values vary across individuals and market segments. In defining the analysis we pay close attention to how values of crowding vary with journey duration and the travelling environment (especially standing, or sitting) and, following a comparison of the results with the findings of the transfer price and revealed preference research, develop a family of curves showing the relationship between crowding penalties and the level of crowding.
Association for European Transport