Due to the big increase of vehicle ownership and the use of the car in the netherlands, congestion arose on the dutch road network in the sixties and the seventies. Global analyses of this congestion show that this had led not only to important losses in journey times but also to a decrease of traffic safety. The accident rate on road sections with congestion was almost twice that on motorways on which only the number of vehicles drove for which the road was designed. Lack of space and lack of money and increased social opposition to a further extension of the road network made new solutions desirable. Because most congestion was found on the road network in the randstad, an urban conglomeration in the western part of holland, it was decided to design an automatic motorway traffic signalling system for this area with the primary aim of increasing the traffic safety and improving the use of the road capacity on these roads. An evaluation was made of the external effects of the system and the results of this evaluation are presented.
Abstract