In April 1990, experiments were started in Sweden with automatic speed surveillance. The experiment comprises a total of 16 sections of road, of which eight consist of two-lane rural main roads with a speed limit of 90 km/h and eight of two-lane urban main roads with a speed limit of 50 km/h. The experiment is based on a statistical experiment, in which pairs of equivalent road sections have been selected. One of the sections in each selected pair has been chosen at random and equipped with automatic speed surveillance. The two sections are designated the test section and control section. In this system, the speeds of passing vehicles are recorded at fixed installations provided with cameras photographing vehicles exceeding a certain predetermined speed. The registration number of a vehicle is noted from the photograph. The vehicle owner is then contacted to identify the driver with the aid of the photograph. Each test section was provided with two camerasites with varying distances between them and different surveillance direction. On nine sections, two (in one case, three) consecutive cameras faced the same direction, while on seven sections surveillance was performed with one camera in each direction. The distance between the cameras varied from approximately 500 metres to 11 kilometres. In all cases, the cameras were preceded by signs warning drivers of automatic speed surveillance in their particular direction. Repeated speed measurements and observations of accidents have been performed on both the test and control sections before and during the experiment. On all test sections, speeds have been recorded by following a sample of cars before and after the experiment. The number of cars followed was the same in all surveillance periods on the particular test section, but varied between the sections. By using these car following studies, it has been possible to describe the direct effect on speeds as a result of automatic speed surveillance, both locally in connection with automatic speed surveillance and totally over the test section. The experiment comprised a total of 110 km of rural main roads with a speed limit of 90 km/h and 17 km of urban main roads with a speed limit of 50 km/h, together with approximately the same length of control sections. At the end of the experiment, surveys based on questionnaires were conducted with different samples of car owners to determine their experience and attitudes regarding automatic speed surveillance. (A).
Samenvatting