Household Mobility Tool Ownership: Modeling Interactions between Cars and Season Tickets

Document Type

Journal Article

Publication Date


Subject Area

planning - surveys, ridership - mode choice, technology - ticketing systems


Travel behavior, Surveys, Stated preferences, Small cars, Probits, Probit models, Passes (Transportation), Optimization, Optimisation, Mode choice, Modal substitution, Modal choice, Mobility, Large automobiles, Karlsruhe (Germany), Interactive stated response, Households, Econometric models, Decision making, Costs, Compact automobiles, Choice of transportation, Automobile ownership


This paper proposes a framework to better capture the dependencies between mobility tool choices at the household level by allowing not only the modeling for the presence of a tool, but of the exact number of each tool type. The framework is applied to a data set collected in 2000/2001 in Karlsruhe, Germany, via an interactive web-based stated response survey. Survey respondents could optimize their household mobility tool sets through on-line feedback concerning the estimated costs of the sets. Bivariate ordered probit models are estimated for three combinations of mobility tools: season tickets (i.e., monthly transit passes) and cars, season tickets and small cars, and season tickets and large cars. In all instances, strong substitution effects are found; i.e., as the number of season tickets increases, the number of cars decreases. This finding highlights the need to move beyond simple models of car ownership to comprehensive models of mobility tool ownership in order to avoid misleading results.