UC Irvine Institute of Transportation Studies

The first question addressed in this research is: how is fuel type choice related to car mobility measured, where mobility is measured in terms of overall usage (kilometers per year) and commuting distance? Causality can be anticipated in both directions: a high travel demand might explain the purchase of a car with lower fuel costs, but the ownership of such a car might result in more travel. The second question is: what are the influences of commuting subsidies, public transport season tickets, income and other background sociodemographic variables on fuel type choice and car mobility? 

A joint continuous/discrete choice demand model is specified in terms of a set of dynamic simultaneous equations. The endogenous (dependent) variables are car fuel type, car usage, and commuting distance, each measured at two points in time. Car fuel type is treated as a three category discrete variable ordered in terms of fuel cost; usage is a continuous variable; and commuting distance is a censored continuous variable (having the censoring value zero for households with no workers outside the home location). The model is restricted to single-car households, and is estimated on a pooled sample of the Dutch National Mobility Panel for the years 1984-1988. Elasticities are calculated for each endogenous variable as a function of the other endogenous variables and certain exogenous variables.