Goal
Which effects can be achieved with demerit points systems?
The effects can be divided into three types. Demerit points systems can be deterrent, selective, and educational.
A demerit points system should restrain road users from offending deliberately. However, the deterrent effect appears to be limited. In the first year after the introduction of a demerit points system all drivers will drive more carefully for fear of losing their driving licence. That is why there are fewer casualties shortly after the introduction, but this effect is only temporary. If drivers discover that the chance of being caught is not as large as they originally thought, they relapse in their old behaviour and the number of crashes goes up.
In principle, a demerit points system can trace repeat offenders even before they are involved in a crash. This selective effect, however, is slight in practice since many traffic offences are not detected if the enforcement effort is insufficient. This is a result of the way in which demerit points can be imposed, viz. by being halted in traffic.
Finally, a demerit points system can also act correctively. The road safety effect of this system as an educational tool, which uses a special training for recidivists, has not yet been demonstrated.