![]() $3,700 per signal and 26 person-hours of work for most agencies). Shown signal timing to be a cost-effective expenditure of resources (with an average cost of Significant factor contributing to suboptimal signal retiming, even though many studies have The literature and survey review and the case study evaluation produced several notableįindings on the current state of traffic signal retiming. Tion and shared control include technical barriers, and institutional legal and liability Signal coordination across agency boundaries. ![]() Technologies to reduce the labor required to conduct field evaluations. Transit agencies may be able to use emerging Simulation and traffic detectors are used toĪ lesser extent for evaluation purposes. Rates, and emissions and fuel consumption. Most agen-Ĭies track performance measures through delays, stops, route travel time, accident Observations at intersections, crash records analysis, and public feedback. Signal timing performance evaluation methods, such as travel time measurements, ⢠Gies for identifying the number of timing plans needed and their periods of use are in Timing plans for weekends, holidays, and special events. Generally employ from three to seven daily timing plans, with two to three separate Retiming interval of 30 to 36 months, largely because of limited resources. Most agencies exceed the advised signal ⢠Policy, management, and planning practices. In fine tuning, monitoring traffic, and determining timing needs, but other process Closed-circuit television is more frequently being used to assist To prepare timing plans, but the traffic movement data used in the software are usu-Īlly collected manually, which decreases efficiency and increases the costs of the sig. Most agencies use standard retiming software Vehicle and pedestrian safety, as well as minimizing delay.ĭata collection requirements and intersection analysis, including phasing, retiming ⢠General signal control issues such as selecting intersections for coordination and â¢ĭetermining different classes of intersection users. The practices covered by this synthesis include the following: Studies, the authors followed up with the 7 agencies that responded and were able to acquireĪdditional statistical and anecdotal information. Of the 17 agencies solicited for the case Information not addressed in the prior survey. For the case studies, the authors prepared an in-depth questionnaire to solicit detailed Lected information for this synthesis through a literature review, a review of two large-scaleĪnd two narrowly focused surveys of transit agencies, and a series of project case stud. Processes used to develop, install, verify, fine-tune, and evaluate the plans. It includes the planning needed to develop signal timing plans and the This synthesis reports on the practices that operating agencies currently use to revise Interagency cooperation may allow transit agencies toĪssign more resources for signal timing or to improve the use of existing resources. ![]() These new approaches may includeĬooperative action with other regional agencies, often with the assistance or leadership of a To streamline the use of new and existing resources. Process in order to improve the quantity and quality of the traffic signal data collected and Transportation agencies may need to explore new approaches to the signal retiming Information may be using faulty data to analyze and time their traffic signals. As a result, even agencies that do make an effort to compile traffic signal Signal timing, and many existing traffic data collection programs do not assess the quality Transportation agencies surveyed (43%) do not regularly collect and analyze traffic data for The Urban Mobility Report and National Traffic Signal Report Card publicize the need forĪnd public benefit of traffic signal retiming: these reports indicate that almost half of the Resources, few agencies have developed regular programs to carry out the retiming process. That retiming traffic signals is a cost-effective expenditure of transportation agency Increased fuel consumption, among other concerns. Travel delays, increased accident rates, increased pollution from vehicle emissions, and Traffic signals that are not timed to coordinate efficiently with vehicular traffic can cause Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages. Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book.
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