DEMAND FOR CLEAN-FUEL VEHICLES IN CALIFORNIA - A DISCRETE-CHOICE STATED PREFERENCE PILOT PROJECT

A study was conducted to determine how demand for clean-fuel vehicles and their fuels is likely to vary as a function of attributes that dis tinguish these vehicles from conventional gasoline vehicles. For the p urposes of the study, clean-fuel vehicles are defined to encompass bot h electric vehicles and unspecified (methanol, ethanol, compressed nat ural gas or propane) liquid and gaseous fuel vehicles, in both dedicat ed or multiple-fuel versions. The attributes include vehicle purchase price, fuel operating cost, vehicle range between refueling, availabil ity of fuel, dedicated versus multiple-fuel capability and the level o f reduction in emissions (compared to current vehicles). In a mail-bac k stated preference survey, approximately 700 respondents in the Calif ornia South Coast Air Basin gave their choices among sets of hypotheti cal future vehicles, as well as their choices between alternative fuel versus gasoline for hypothetical multiple-fuel vehicles. Estimates of attribute importance and segment differences are made using discrete- choice nested multinomial logit models for vehicle choice and binomial logit models for fuel choice. These estimates can be used to modify p resent vehicle-type choice and utilization models to accommodate clean -fuel vehicles; they can also be used to evaluate scenarios for altern ative clean-fuel vehicle and fuel supply configurations. Results indic ate that range between refueling is an important attribute, particular ly if range for an alternative fuel is substantially less than that fo r gasoline. For fuel choice, the most important attributes are range a nd fuel cost, but the predicted probability of choosing alternative fu el is also affected by emissions levels, which can compensate for diff erences in fuel prices.