A key problem for local authorities is the lack of robust techniques for evaluating crash risk at high-volume, urban, priority-controlled intersections. Some crash prediction modelling tools are available, but they do not accurately predict crash rates at the higher-volume priority-controlled intersections, where at times, there are limited gaps in main road traffic flows, which often gives rise to safety problems. This research project aimed to develop safety models that would enable practitioners to better understand crash risk at urban intersections.
Video data was collected at eight Christchurch sites for the peak traffic periods. The data was analysed to measure vehicle headway and the gap acceptance profile (bell graph) of drivers making two movements - the right turn in and the right turn out. This pilot study established a framework procedure and presents the results from the data analysis.
Further work is required to collect data from a larger sample of priority-controlled intersections across New Zealand. Ideally, automated analysis of video data would be applied. Using this additional data, the development of a safety model linking gap selection and crashes should be possible.