The impact of red-light surveillance cameras on road safety in Singapore

For over a decade Singapore has been operating a red-light surveillance camera system to enhance road junction safety. A study, based on a nine-year traffic accident count series, was undertaken to evaluate the impact of the cameras on casualty accidents at signalised junctions. The general accident characteristics at road junctions were first reviewed, followed by an examination of the accident patterns at a highly representative sample of 125 camera junctions. Comparative analysis was also performed on a sample of 42 high-accident-risk treatment junctions and a similarly matched sample of 42 comparison junctions. Thestudy indicated that head-to-sidecollisions were the predominant junction accidents. An overall accident reduction of about 16% was observed for the camera junctions, with over three-fifths of the reduction in the head-to-side category. The treatment-vs-comparison analysis showed that the net reduction in the total accident counts was about 9%, with more than two-thirds contribution, from the head-to-side collisions. The results are found to be in agreement with findings contained in various studies reporting that the installation of surveillance camera systems can contribu te positively towards safety improvements. Traffic accidents at road junctions are a major road safety problem. In Singapore, recent statistics (Singapore Traffic Police 1996) showed that about a third of the reported cases of fatal and injury trafficaccidents occurred at junctions, of which 15% were ascribed principally to drivers disobeying the traffic signals. A study of a recent sample of 4526 police crash reports from four urban areas in the United States showed that 56% of the crashes occurred at junctions, and that of these junction crashes 8% (212 case) were due primarily to drivers running the traific signals (Retting et al. 1995). A study in Mew South Wales found that 18% of reported casualty collisions at signalised junctions involved vehicles running the red-light signal (Hulscher et al. 1980). it is also generally the case that 'red-running' accidents are the more severe crash type. Engineering and non-engineering measures must be employed hand-in-hand to tackle the problem of red-light violations and associated traffic collisions at signalised junctions. At signalised junctions improvements in skid resistance, roadway lighting and signal visibility are typical engineering solutions but these alone cannot adequately deal with the complexity of junction safety problems. In view of this, a feasible, complementary non-engineering measure is to placean unmanned traffic surveillance system to provide automated enforcement in order to manage the level of violations and hence, the rate of accident occurrences. One such automated enforcement system is the red-light surveillance camera system which has been in operation in Singapore as well as in many countries such as Australia, New Zealand, the United Kingdom and Malaysia. In this paper, the impact of red-light cameras on safety at signalised junctions is investigated based on an analysis of fatal and injury accident data at a sample of camera and comparison junctions. Several studies concerning red-light cameras are first reviewed. Abrief description of the red-light camera program in Singapore is then given, as well as the data and methodology used in the study. An overview of the accident situation in Singapore follows and the results of the analysis at selected junctions are presented.