A general problem of enforcement of traffic laws in industrialized countries is the limited priority this problem gets in relation to criminal offences. Furthermore the available police manpower often is not being employed efficiently. Therefore more and more automated warning and enforcement systems are being applied on the roads. These systems can be put into operation locally, on a stretch of road and in a network. Several experiments have been conducted in the Netherlands in this field with positive effects on speed behaviour and road safety. Automatic speed warning at the approach of an intersection in The Hague gave a reduction in mean speed of 5 km/h. The possible effect on accidents was calculated based on a scenario; a reduction of several tenths of percentages in accidents was the result. In the province of Friesland the speed limit at the approach of the intersection was reduced from 100 to 70 km/h and an automatic speed warning sign flashes when cars were driving faster than 70 km/h. In the beginning a police car was posted periodically at that intersection. The mean speed went down from around 80 km/h to 63 km/h, and the percentage of speeders remained at about the same level (lowered speed limit!). On four provincial road stretches with a speed limit of 80 km/h an automatic speed warning and enforcement system resulted in a total average reduction of the mean speed from 78 to 73 km/h and the percentage of speeders went down from 40% to 10%. The total number of accidents was reduced with 35%. Projects on enforcement of speed on a provincial road network have just started in the Netherlands. The main aspect is the exclusive use of inconspicuous radar and camera that to be moved after 2 hours of enforcement to another location. Feedback information is given to all passing vehicles downstream of the enforcement site showing 'Your speed has been checked. Police'. This campaign is combined by periodical information campaigns to increase the subjective risk of being caught. In a separate part of one province conventional enforcement technique stopping speeders along the road will be evaluated too.
Abstract