Developing an objective warrant system for red light cameras

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University of New Brunswick
Photo-enforced traffic signals, or red light cameras (RLCs), have been shown to be an effective countermeasure to address red light running (RLR). Unfortunately, RLCs are often installed at specific intersections in reaction to public/political pressure or based on subjective recommendations from traffic engineers or enforcement officers. There is no existing analytical methodology that can objectively determine where RLCs would prove to be most effective. The predominant goal of this research was to develop a robust procedure that enables road authorities to make objective decisions about the installation of RLCs. The resulting worksheet-based warrant system was developed to provide an efficient methodology that determines if an intersection is an appropriate candidate for RLCs. The worksheet combines a predictive model that forecasts the expected proportion of daily RLR incidence, collision modification estimates associated with installing RLCs, and an economic feasibility evaluation. A threshold value for the warrant system was determined to be 42,000, which represents the minimum number of red light violations that must occur each year to warrant RLCs based on cost-recovery. Jurisdictions are encouraged to use the worksheet to assess a network of urban signalized intersections to determine appropriate locations to install RLCs and their relative priorities.