Item B: West 11th Transportation Corridor Study

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TABLE 7-5: AM Peak Performance Comparison of Left Turn Phasing Types Scenario Travel Total Stops Average Fuel Time (hr) Delay (#) Speed Consumed (hr) (mph) (gal) Existing Signal Operation 286 108 12,045 24 440 1. 90 Second Cycle Length (Existing 279 101 10,355 24 422 left-turn phasing) 2. 90 Second Cycle Length 279 100 10,328 25 421 (Modified left-turn phasing) Note: Performance Measures Determined from Synchro 6.0 Measures of Effectiveness thth 6 Avenue/7 Avenue Signal Timing thth The traffic signals along 6 Avenue and 7 Avenue between Chambers Street and Garfield Street were evaluated to determine if new traffic signal timing would provide improved traffic operations. The original thth limits of the analysis also included a grid of four intersections along West 6 Avenue and West 7 Avenue between Garfield Street and Chambers Street. The limits for this project area were extended to include the thth signal at West 8 Avenue at Chambers Street, since this signal is 500 feet south of West 7 Avenue/Chambers Street and has an influence on the traffic flow on Chambers Street. thth Currently, the traffic signals along West 6 Avenue and West 7 Avenue between Garfield Street and thth Chambers Street and the intersection of Chambers Street and 8 - th and 7 Avenue are an east/west one-way couplet, while Garfield Street and Chambers Street are both two- thth way streets and provide connections between 6 and 7 Avenue. Currently, all five signals operate at a cycle length of 90 seconds during the AM (7:30 to 8:45 am) and PM (3:00 to 6:00 pm) peaks. It should be noted that the signals in this project area are part of a larger signal system that extends farther thth to the east towards downtown and includes additional intersections along 6 Avenue and 7 Avenue that are outside of this assessment. The signal timings were adjusted approximately three to four years ago thth when I-105 was reconstructed. The signals along 6 and 7 Avenues were retimed to take into account the new intersection geometry at Jefferson and Washington (which drives the cycle length of the system). The thth timings at Chambers and Garfield were fine tuned to provide progression along 6 and 7 Avenues while minimizing the queues on Garfield and Chambers. th Excessive queuing was observed on 7 Avenue from Chambers Street extending to Garfield Street, during short periods of 15 to 20 minutes during the PM peak hour. A lane imbalance results in a large percentage of vehicles in the eastbound left-cles. If the side street th gapped out, additional time was added to 7 Avenue, which helped to serve the eastbound vehicles. Signal Timing Evaluation This group of intersections will operate efficiently at a limited number of cycle lengths. A cycle length that th is too short will have trouble clearing all the vehicles at the intersections of 6Avenue/Chambers Street th thth and 7Avenue/Chambers Street while providing adequate progression along 6 and 7Avenues. A cycle length that is too long will produce queues on the side streets and in the left turn lanes that may exceed storage lengths due to the close spacing of the intersections. Several scenarios were evaluated with cycle th West 11 Avenue Corridor Study September 4, 2009 City of Eugene P07265-003-000 56