During April - October 1989 the police in the cities of Linköping and Norrköping carried out experiments with intensified radar surveillance. The aim of the project is to study the effects of intensified radar surveillance on speeds, its influence on other surveillance activities and traffic safety. Surveillance allocation over time has been studied, too. The urban areas of Linköping and Norrköping were divided into two and three sub-areas respectively in order to investigate motorists' ability to notice local differences in surveillance intensity and detection risk. Results are based on analysis of the police statistics, speed measurements by the police and the VTI, accident statistics from Statistics of Sweden and the local road administration, motorist interviews and an inquiry answered by the police officers involved. The results indicate the massive surveillance over a longer period of time reduces speeds substantially with relatively long-lasting effect in the area where surveillance is carried out, but that the spreading effect to neighbouring areas is moderate or non-existent. Total number of accidents reported by the police decreased in the test areas. The police statistics show that the number of interventions against infringements of other traffic legislation increased in 1989. Roadside interviews indicates that the police have very strong support for radar surveillance in urban areas. (A)
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