Traffic Signal Retiming Practices in the United States

This synthesis reports on the practices that operating agencies currently use to revise traffic signal timing. It includes the planning needed to develop signal timing plans and the processes used to develop, install, verify, fine-tune, and evaluate the plans. The author collected information for this synthesis through a literature review, a review of two large-scale and two narrowly focused surveys of transportation agencies, and a series of project case studies. For the case studies, the author prepared an in-depth questionnaire to solicit detailed information not addressed in the prior survey. Of the 17 agencies solicited for the case studies, the author followed up with the 7 agencies that responded and was able to acquire additional statistical and anecdotal information.