The paper discusses and presents hypotheses on two forms of behavioural adaptation; risk compensation and "safety compensation", i.e that road users adapt to risk by reducing speed or increasing attention. The first question that is addressed behavioural adaptation sometimes occurs, i.e what motives may lead to behaviour adaptation. Motives are a necessary, but not a sufficient condition for behavioural adaptation to occur. The second question that is addressed is how motives for adaptation are expressed in driver behaviour. This is basically a question of what possibilities drivers have to compensate for safety measures and for risk factors the third question that is addressed is when and where drivers compensate for risk, i.e before a trip starts, it may occur during the trip (tactical level), and finally it may occur on the operational level as unconscious adjustments of speed or attention. The final question that is addressed is what types of safety measures that are most likely candidates for risk compensation. The focus is on whether measures that reduce probability of accident are more likely candidates for risk compensation than measures that reduce the consequences of an accident. The paper summarises the results of the theoretical part of a three-year research programme on risk compensation. The hypotheses presented are to some degree supported by preliminary empirical results from a pilot study. (A)
Samenvatting