In this paper it is argued that conventional analyses of road user adaptation to traffic law enforcement, based on parametric rational-choice theory, are flawed. Such analyses only consider road-user actions as a response to enforcement level and penalty size and do not simultaneously consider enforcement as a response to road-user behaviour. If each party is considered a rational agent who adapts to the other's behaviour, the proper way to analyze the outcomes is by the way of game theory. A game-theoretic model is presented and the main implications are: (i) most attempts at enforcing road traffic legislation will not have any lasting effects, either on road-user behaviour or on accidents; (ii) imposing stricter penalties (in the form of higher fines or longer prison sentences) will not affect road-user behaviour; (iii) imposing stricter penalties will reduce the level of enforcement; (iv) implementing automatic traffic surveillancetechniques and/or allocating enforcement resources according to a chance mechanism, and not according to police estimates of violation probability, can make enforcement effects last, but both alternatives are difficult to implement. Relevant empirical studies are reviewed, and they seem to support the conclusions arrived at by the game-theoretic model. (A)
Abstract