Traffic signal warrants

The adequacy of the existing warrants and the need for revised or additional warrants in meeting current needs for determining whether a traffic signal should be installed were evaluated. The research effort included a state-of-the-art review and survey of current practices, empirical studies of traffic operations at intersections using time-lapse photographic techniques, acquisition and statistical analysis of a large data base describing accidents at intersections, design and implementation of a large-scale traffic simulation study, development and implementation of analytical models, synthesis of results and specification of recommended traffic signal warrants, design and distribution of a pilot warrant evaluation survey and subsequent refinement of recommended warrants, and preparation of a study design for field verification of the recommended warrants. The results of the studies are briefly outlined. Ten warrants were recommended. These warrants relate to: vehicular volume, peak-hour volume, hazard volume, delay, pedestrian volume, school crossing, accident experience, systems, and downgrading.