Ingo Koßmann

• In order to enhance road safety, it is necessary to make road users change their behaviour. There are two forms of police enforcement: punishment for breaking traffic regulations and rewards for rule-conformist behaviour. Punishment does not appear to produce long term changes. There are two main reward strategies: individual and group dependent rewards. Individuals who are members of a clearly defined group have good prospects of winning prizes in a lottery. The strategy of the delegated group dependent reward is based on a donation to a social institution. Traffic safety is a conflict of interests, and game theory considerations can be applied. Results of German and Dutch studies confirm hypotheses based on the game theory concept. Traffic behaviour mostly depends on expectation of others' behaviour. Successful strategies of reward should always be based on individual settlements of the rewards. More investigations are needed. Strategies of group dependent reward are not recommended. The size of reward and probability of winning it should be linked to rate of participation: the greater the participation, the greater the value of reward and probability of winning it. Every driver has a threshold from which he is prepared to change his traffic behaviour for a reward.