Samenvatting
On May 1, 1988 a differentiation of the speed limit on the Dutch motorways was introduced. On some road sections on it come possible to driver 120 km /h and on other road sections the 100 km /h speed limit is still mandatory. By a publicity campaign and an enhanced police control the drivers were motivated to change their speed behaviour. A before and after study was done to determine the effects of the campaign and the police control.