Investigating mode choice preferences in a tradable mobility credit scheme

Abstract

Tradable Credit Schemes (TCS) are gathering increasing attention in the transportation sector as an alternative to traditional pricing measures. TCS could foster the shift to more sustainable modes and limit the production of negative externalities while promoting social justice and equity. Current research has a strong focus on modeling market equilibrium prices, charging designs, social acceptance, and equity aspects. However, most modeling approaches have to make assumptions about user preferences due to a lack of empirical evidence on user’s behavior in such a system. This paper presents the results of a stated mode choice experiment with over 1,000 participants conducted in Munich, Germany, to examine the trade-offs between travel time, private and external travel costs, and other level-of-service attributes within a TCS. A Mixed Multinomial Logit (MMNL) model applied to the data collected revealed three main findings. First, the results confirm that the participants seem to understand the complexity of TCS and behave rationally. Secondly, respondents reacted more sensitively to credit charges the smaller their monthly remaining credit budget was and the more days of the month were left. Finally, the variance of the associated values of travel times was found to be largest for cars, indicating higher values and hence greater discomfort when considering their imposed external costs. To conclude, this paper sheds light on mode choice preferences in the context of a hypothetical TCS and suggests directions for future research.