Evaluation of Transit Priority Treatments in Tennessee

University Transportation Centers Program2019PDFTech ReportChimba, DeoIkiriko, SotonyeTennessee State UniversityWestern Michigan University. Transportation Research Center for Livable CommunitiesUnited States. Department of Transportation. University Transportation Centers (UTC) ProgramWestern Michigan University. Transportation Research Center for Livable CommunitiesTennesseeUnited StatesTraffic signal priorityLevel of serviceTraffic actuated controllersEvaluation and assessmentCitiesPublic transitVehicle actuated programming (VAP)VISSIMGreen extensionRed truncationTRCLC 17-11TRCLC 17-11Final Report 8/15/2017-6/30/2019Many big cities are progressively implementing transit friendly corridors especially in urban areas where traffic may be increasing at an alarming rate. Over the years, Transit Signal Priority (TSP) has proven to be very effective in creating transit friendly corridors with its ability to improve transit vehicle travel time, serviceability and reliability. TSP as part of Transit Oriented Development (TOD) is associated with great benefits to community liveability including less environmental impacts, reduced traffic congestions, fewer vehicular accidents and shorter travel times among others. This research have therefore analysed the impact of TSP on bus travel times, late bus recovery at bus stop level, delay (on mainline and side street) and Level of Service (LOS) at intersection level on selected corridors and intersections in Nashville Tennessee; to solve the problem of transit vehicle delay as a result of high traffic congestion in Nashville metropolitan areas. This study also developed a flow-delay model to predict delay per vehicle for a lane group under interrupted flow conditions and compared some measure of effectiveness (MOE) before and after TSP. Unconditional green extension and red truncation active priority strategies were developed via Vehicle Actuated Programing (VAP) language which was tied to VISSIM signal controller to execute priority for transit vehicles approaching the traffic signal at 75m away from the stop line. The findings from this study indicated that TSP will recover bus lateness at bus stops 25.21% to 43.1% on the average, improve bus travel time by 5.1% to 10%, increase side street delay by 15.9%, and favour other vehicles using the priority approach by 5.8% and 11.6% in travel time and delay reduction respectively. Findings also indicated that TSP may not affect LOS under low to medium traffic condition but LOS may increase under high traffic condition.136