Integration of unobserved effects in generalised transport access costs of cycling to railway stations
This paper examines the role of perceptions and attitudes in railway station accessibility. We add unobserved (latent) variables to the Generalised Transport Access Cost (GTAC) of cycling to Dutch railway stations in the metropolitan area of The Hague – Rotterdam. A hybrid discrete choice model was estimated for access mode and two latent variables which were obtained through factor analysis: perception of station environment (including factors such as the users’ judgement of the station, assessment of travel information, presence of high speed trains) and perceived connectivity (including factor such as the evaluation of punctuality and the frequency of the train and quality of bicycle infrastructure). The estimated individual utility was applied to a station access cost index. A comparison between standard logit and hybrid utility functions identifies improvements in the utility-based measures by using discrete choice models. Utilities are computed by station departure, postcode of residence and neighbourhood. The results show, first, that omitting unobserved effect in utility-based measures tends to lead to overestimations of the accessibility levels. Secondly, different variations in accessibility levels are revealed, by size of railway stations and urban areas. Finally, the results highlight stronger effects of network connectivity impedances than station environmental impedances in generalised transport costs.