Higher penalties do not affect drink driving, probably because the current penalties are already rather severe. Higher penalties do affect some violations however, such as speeding, non-usage of seatbelts and red light negation, but only on those roads that are frequently policed [17].
Drink driving
Higher penalties for drink driving are not effective. In the Netherlands, in 1992, penalties for drink driving became substantially higher (higher fines and a speedier licence suspension), but this did not lead to a decrease of drink driving [20]. Instead, drink driving increased somewhat, probably also because the enforcement level was strongly reduced. International studies do not show any effect either. Several American state laws imposing imprisonment for first-time drink-driving offenders did not appear to have any effect, or only a slight effect, on the prevalence of drink driving [21]. In Australian New South Wales, doubling the penalty for drink driving (in 1998) was not associated with a reduction of drink driving, nor with the number of crashes [22]. Nor did a different Australian study find any relation between penalty severity and the chance of an offender having to re-appear in court for drink driving [23].
Why penalty severity does not affect drink driving may be explained in several ways. Firstly, a lot of people who participate in traffic having consumed too much alcohol are alcohol-dependent. It is very hard for them to reduce their alcohol consumption, which increases the chance that they will persist in their offensive behaviour. Secondly, the chance of apprehension experienced by the offenders is too small. If offenders are caught for the first time, they will not immediately conclude that the chances of apprehension are significant. After all, years of undiscovered drink driving have often preceded the apprehension. Finally, it is possible that persistent drink drivers are sensitive to the so-called ‘gambler’s fallacy’, for which Pogarsky and Piquero [24] have found proof. Drink drivers who have gone undetected for years, wrongly assume that their chances of being caught have diminished after their first apprehension and penalty. For them, apprehension and penalty do not lead to a higher subjective probability of detection, but rather to a lower probability.
Other violations
For other violations, a (small) effect of higher penalties is often found. International research into red light negation, based on Israeli and US data, shows that every penalty increase by 1% led to a decrease in red light negation by 0.2 % [25]. Dutch research, based on the speeding penalty increases of 1 April 2008 and 1 January 2010, resulted in a similar estimate [26]: if the penalty increases by 1%, the speeding violations (detected by road section control systems) decrease by 0.23%. In both studies, the effects of the penalty increases were measured shortly after the increase and especially on those roads which were usually policed. So the estimate possibly concerns time- and place-bound behavioural effects.
Higher penalties also appear to increase seat belt use. A Norwegian study showed that a 100 NOK (10 €) penalty increase for car occupants not wearing a seat belt was related to an increase in seat belt use by 2.5-5% in rural areas and by 10% in urban areas [27]. In the United States [28] this correlation was also found: a penalty increase from 25 to 60 dollars resulted in 3-4% increase in seat belt use, and a penalty increase from 25 to 100 dollars in a 6-7% increase.
