Rational Drivers, Irrational Enforcers, and Road Safety

Abstract

Using Italian data, this article presents an econometric investigation of the effects on infractions and accidents of the introduction of a demerit point system (DPS), as an additional sanctioning mechanism for traffic infringements. Our main finding is that the coming into force of the DPS produced only a temporary and weak effect, while the announcement of the decision of the Italian government to introduce the new penalty system (occurred more than two years before the introduction of the new penalty system) exerted a stronger deterrent effect on the behavior of drivers, and thus on the number of recorded infractions. The evidence on this sort of announcement effect together with that on the implemented level of enforcement, which remained constant during the overall examined period, suggests that the Italian DPS has been prevented by exerting a lasting deterrent effect because drivers have rationally responded to incentives through a learning mechanism. Precisely, once Italian drivers learned that, neither after the government's announcement nor subsequently the coming into force of the DPS, the probability of being detected and thus the perceived expected sanction increased, they re-adapted their degree of compliance with the traffic law to the previous lower levels. Thus, further changes in the implementation of the Italian DPS appear desirable in order to make the new system effectively works.

Keywords: Demerit Point System, Compliance, Deterrence, Road Safety, Traffic Law Enforcement

JEL Classification: K32, K42