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78 CHAPTER SEVEN CONCLUSIONS INTRODUCTION teria have been applied, including ridership, service fre- quency, and transit delay and speed. This synthesis report offers a review of the application of a A majority of transit agencies (54%) install TSP as an number of different transit preferential treatments in mixed unconditional strategy, although conditional priority is traffic. It is highlighted by the presentation of the results of a increasing in application. survey of transit agencies and traffic agencies related to tran- Improving signal timing and coordination were identi- sit preferential treatments on urban streets. The survey results fied (by almost half of the survey respondents) as the are supplemented by a literature review of 23 documents on primary passive TSP applied. the subject; a more in-depth case study evaluation of prefer- Green extension/red truncation is the most popular sig- ential treatment application in four cities--San Francisco, nal priority. Seattle, Portland (Oregon), and Denver; and what are the Most transit agencies (80%) do not have formal com- warrants, costs, and impacts associated with different treat- prehensive transit preferential treatment programs, but ments, based on all of the information obtained. instead address transit preferential treatment needs and projects on a case-by-case basis. This final chapter reviews the decision-making process, A slight majority of the transit agencies (52%) have which can be applied in deciding which preferential treat- intergovernmental agreements with the traffic engineer- ment might be most applicable in a particular location. Also, ing jurisdiction(s) in their service area. the types of items to be addressed in intergovernmental agree- Transit agency involvement in transit preferential treat- ments and monitoring programs to develop and evaluate such ment development focuses on initially identifying and treatments are presented. Finally, areas for future research on locating treatments (85% of respondents), and design the topic are suggested. of improvements monitoring their performance upon implementation (each 52%). Only slightly more than half the transit agencies design the improvements, and a lesser percent construct improvements. SURVEY RESPONSES Eighty urban areas in the United States and Canada were con- Twelve traffic engineering jurisdictions responded to the tacted for the transit/traffic survey (30 with combined bus and traffic agency survey. Because of the low number of responses light rail and/or street systems, and another 50 with just bus it is difficult to identify a composite trend in opinion on the part of traffic engineers on transit preferential treatments. systems); with 52 transit agencies and 12 traffic engineer- Nonetheless, there were some notable trends in the responses: ing jurisdictions responding (80% response rate). A total of 197 individual preferential treatments were reported on the All traffic agency respondents indicated that they are survey forms. In addition, the San Francisco Municipal involved with operating and maintaining transit prefer- Transportation Agency submitted spreadsheets that identi- ential treatments, with a majority (58%) also involved in fied another 400 treatments in San Francisco alone. designing improvements and monitoring performance. The traffic agencies were least involved in identifying The transit agency survey responses revealed the follow- and locating treatments. ing insights on transit preferential treatment application: Median transitways and exclusive lanes were perceived to have the greatest impact on general traffic operations, Transit signal priority (TSP) (67% of respondents), with limited transit stops the least impact. queue jump and bypass lanes and limited stops (each Early green/red truncation is the traffic signal timing 52%), and exclusive transit lanes (46%) are the most modification strategy used most by traffic agencies. popular treatments that have been applied. Other iden- Most of the traffic agencies use either optical/infrared tified preferential treatments (median transitway, spe- or inductive loops for transit vehicle detection. cial signal phasing, curb extensions) each had 25% or When monitoring TSP events, the traffic agencies indi- less with respect to application. cated they identify the number of possible TSP events, There are no standard warrants being applied to identify the number of actual TSP events, and the duration of the need for particular treatments. Several different cri- TSP events.