Item B: West 11th Transportation Corridor Study

Home Browse Search

distance between intersections (0.7 miles) and the fact that the platoon is more likely to fall apart due to the th large spacing between signals. The intersection of West 11 Avenue and Green Hill Road operates more efficiently as an actuated free intersection (as it does today) than to coordinate it with the intersections to the east because of the long distance (1 mile) between Green Hill Road and the traffic signal at North Terry Street. Cycle Lengths Currently, the traffic signals between City View Street and the Fred Meyer driveway operate at a cycle background cycle length. Several scenarios were evaluated with cycle lengths ranging from 80 seconds to 120 seconds. Phase Sequences th The traffic signals along West 11 Avenue have a mixture of protected-only left-turn phasing and th protected/permissive left-turn phasing along West 11 Avenue. Currently all of the traffic signals operate with leading left-turn phasing. Two scenarios were evaluated. The first scenario assumed that the existing left-turn phasing would not change. Those intersections that currently operate with protected-only phasing will continue to operate with protected-only. Those intersections that currently operate with protected/permissive (doghouse head) will continue to operate as protected/permissive. The optimized timings use lagging left-turn phasing at some traffic signals that operate with protected-only left-turn phasing. The intersections that operate with protected/permissive left-turn phasing were assumed to operate with leading left turns to avoid the left-turn 28 trap. The second scenario assumed that the existing doghouse signal heads would be replaced with four-section flashing yellow left turn heads. This will allow lead/lag phasing operations without the left-turn trap. This scenario also assumed the existing protected-only left-turn phasing at the intersections between Commerce Street and Bailey Hill Road would continue to operate with protected-only left-turn operation. (Existing left-turn phasing) PM Peak th Based on the Synchro analysis, it was determined that operating the signals along 11 Avenue as two systems shows the greatest improvement. The signals between City View Street and Bailey Hill Road would operate with a 100 second cycle length, while the signals between Bertelsen Road and Terry Street would operate with a cycle length of 110 seconds This would result in reductions of 4 to 10% in vehicle delay, stops and fuel consumed.Table 7-2 shows a comparison of the performance measures from Synchro for each of the scenarios. 28 -between the leading phases and lagging phases. When the doghouse indication turns yellow for the leading direction, the left turns and the through traffic must clear the intersection. In the opposite direction, the doghouse indication still shows the green ball (and then the lagging left turn green arrow). The left-turn trap conflict involves the left turn vehicle trying to clear the intersection (yellow indication) while the opposing through vehicle has the green ball. th West 11 Avenue Corridor Study September 4, 2009 City of Eugene P07265-003-000 53