Investigation of Factors that Stimulate Car Drivers to Change from Car to Carpooling in City Center Oriented Work Trips

The current study aims to get more insight into the attributes that stimulate car drivers to use carpool as an alternative for their commuting trips in which the car is still the most used travel mode. The study was set up as a stated choice experiment. In the experiment, car drivers were asked to evaluate various hypothetical carpool alternatives. The alternatives were described using eight attributes: travel time to and waiting time at start location, travel time in (carpool) vehicle, uncertainty in travel time, costs of the trip, number of persons in the vehicle, parking situation at work location, car/bike availability at work location, and flexibility of arrival and departure times. Each generated carpool alternative was included in a choice task together with the respondent's current car alternative. The choices were analyzed using a mixed multinomial logit model. The model estimation process showed that almost all attributes significantly influence the attractiveness of carpooling in an expected direction. Most influential are the time and costs related attributes. No significant effect was found for the minimum number of persons in the carpool vehicle.