2004-073 Ordinance - Laserfiche WebLink

Home Browse Search

Evaluation of Intersection Capacity: The EB exit at Stearns Road was evaluated using existing traffic volumes for AM and PM peak hours. The intersection was analyzed under finro conditions: (1) with existing stop sign control, and (2) with proposed signalized control. The proposed signal was analyzed as coordinated with the W B exit and optimized to balance delays on both sides of the interchange. Existing Ramp S-1 Stop Siqn Control The existing intersection was analyzed in the AM and PM peak hours using Synchro 5.0. As would be expected, the major through movements at the intersection perform at a Level of Service A. Three critical movements have unsatisfactory delays: 1. In the AM peak hour, the Ramp S-1 left turn performs at LOS F. The average delay is 255 seconds, with a queue length of 120'. 2. In the AM peak hour, the Stearns SB left turn performs at LOS D. The average delay is 28 seconds, with a queue length of 240'. 3. In the PM peak hour, the Ramp S-1 left turn performs at LOS F. The average delay is 140 seconds, with a queue length of 150'. Proposed Signalized Control The ITE Manual of Signal Design suggests considering left turn phasing when the product of left turn and opposing volumes exceeds 100,000. In the AM peak hour, this value is a whopping 487,509. In the PM peak-hour product is 154,570. A protected left turn phase appears to be recommended for the proposed signal operation at the EB exit A protected left turn phase at the WB exit is not recommended at this time. The PM peak-hour left turn product is 25,764. The minimum cycle length for coordinated signals at the interchange is 70 seconds. Pedestrian movements and clearance intervals were considered in the design. The throat of Ramp S-1 is unusually long, requiring a pedestrian split longer than the needed vehicular split. To address this concern, the pedestrian phase is actuated and moved to the left-turn phase. Keeping the Ramp S-1 pedestrian movement on the coordinated phase would require a longer split, increasing the overall system cycle length, and degrading the capacity of the coordinated system. This office favors an initial design providing the best level of service for vehicular traffic. A pedestrian crossing of Stearns Road at Ramp S-1 is not recommended. This office does not feel a great need exists to cross Stearns Road at this location. Pedestrians destined for the bike path north of I-480 can safely cross Stearns Road at the signal at the WB exit. AM and PM timing plans are proposed. The splits for both timing plans are identical; only the offsets differ. The PM plan is recommended for off-peak operation. The proposed signal operation was evaluated using Synchro 5.0 as well. Stearns Road through movements remain at LOS A with the proposed signalized control. The results for the critical movements cited previously are as follows: In the AM peak hour, the Ramp S-1 left turn performs at LOS C. The average delay is reduced to 24 seconds.