Defensive purchasing, the safety (dis)advantage of light trucks, and motor-vehicle policy effectiveness

We model motor-vehicle choice when a consumer’s utility from a particular vehicle depends in part on that vehicle’s expected safety, and thus on the vehicle choices made by other consumers with which (s)he may collide. Calibration of model parameters suggests that light trucks do impose an externality on cars and that increasing the proportion of light trucks in the fleet harms truck and car owners alike. The marginal private cost of accidents from light truck ownership relative to cars is of ambiguous sign and may even represent a large safety disadvantage. Analyses that omit expected vehicle safety will overestimate the impacts of policies such as gasoline taxes or changes to fuel economy standards on the fleet, and underestimate the impacts of vehicle crash-compatibility design changes.