The Impact of Deterrence Policies on Reckless Driving: The Case of Portugal

In this paper, we test the effect of three different criminal deterrence theory policy tools: criminal certainty, severity, and celerity of punishment. Whereas most criminal deterrence studies in this field focus on the former two components of deterrence theory, this study also examines the potential deterrent effect of the latter component. Using a time-series design with monthly data, we estimate the effects of an increase in the threat of punishment for traffic offenses resulting from a general increase in fines for traffic offenses, an increase in the probability of getting caught with a blood-alcohol concentration (BAC) level outside the legal limits, and the enactment of an “on-the-spot” fine payment policy in Portugal. We find strong evidence to support a severity effect. An increase in the statutory severity of sentence maxima for traffic violations leads to a decrease in accident and injury rates—approximately an average 0.5 percent reduction in monthly accident and injury rates. Changes in the BAC levels and the mandatory swift payment policy did not produce any convincing deterrence impact.