Transcript Document
Problem 2: Moe Rd/Route 146 Intersection Examine issues related to pedestrians & lane utilization in addition to with-site conditions analyses. Analysis Plans 2a: AM Existing: pedestrian effects 2b: PM With-site: lane utilization considerations Characteristics of Moe Rd Intersection Signalized & fully actuated EB & WB approaches are both 3 lanes wide The WB lane tapers to a single lane after the intersection NB & SB approaches are both 1 lane wide Arrival Patterns EB traffic arrives in platoons, discharged from the upstream intersection at the entrance to the Shenendehowa campus WB traffic arrives in platoons, discharged by the Maxwell Drive intersection The platoons tend to arrive on red The NB & SB traffic arrives randomly What Arrival Type would be most appropriate for each approach? EB & WB = Arrival Type 2 NB & SB = Arrival Type 3 Factors that should be considered for this intersection: - Pedestrians - Lane Utilization Observations? Sub-problem 2a: Moe Road AM peak hour Existing Conditions What effects do pedestrians generally have on intersection analyses and operational requirements? They usually conflict with the coincident right-turning vehicles They sometimes require insertion of an all-walk phase with no vehicular movements Consideration of them generally requires modifications to the signal timing How do each of these factors affect the Moe Road intersection analysis? Observations? Moe Road Pedestrian Considerations Exhibit 2-24. M oe Road Treatment for P edestrians Data set Condition P eds Cycle P erformance Length M easure 15 Base Case Y 72 16 SB Max Peds Y 17 w/o Peds N EB WB NB SB OA LT TH RT Tot LT TH RT Tot LT TH RT Tot LT TH RT Tot Delay 12.6 20.6 20.5 25.6 10.9 14.4 22.8 22.8 19.5 19.5 18.2 72 Delay 12.6 20.6 20.5 25.6 10.9 14.4 23.6 23.6 19.6 19.6 18.3 44 Delay 7.8 13.4 13.4 16.5 7.4 9.6 16.3 16.3 13.4 13.4 12.2 What are the effects of boosting the # of pedestrians to the 1700 ped/hr (HCM Max)? Almost Nothing!!! How would the intersection Delays by movement drop by perform if there were no 12.6 – 25.6 sec/veh pedestrians? What has been learned? Make sure to account for pedestrians if they are present at an intersection!!! Lane Utilization ~ 250’ from the intersection the 2 WB lanes merge into 1 What would you expect the driver tendencies to be? Many will desire to pre-position themselves in the lane that does not end (inner lane) HCM lane utilization factor, fLU, is defined as the ratio of the average volume per lane to the volume in the heaviest-used lane Exhibit 2-25. M oe Road Trends in Lane Utilization Data Cycle P erformance Condition P eds set Length M easure 18 19 20 21 Base Case 30%more generated traffic 30%more traffic LU default 30%more traffic LU=0.67 No No No No 50 53 53 53 WB NB SB OA LT TH RT Tot LT TH RT Tot LT TH RT Tot LT RT LT Tot Delay 10.1 23.8 23.6 33.5 13.8 17.3 31.9 31.9 14 14 21.2 95-queue 0.5 20.2 8.9 17 - 11 - 2 - - Ave queue 0.2 11.1 4.5 9.1 - 5.7 - 1 - - Delay 10.9 28.2 34.8 14.7 18.3 36.4 36.4 15 15 23.9 95-queue 0.5 22.6 9.8 18.5 - 12.5 - 2.4 - - Ave queue 0.3 12.5 5 10 - 6.5 - 12 - - Delay 10.9 21.4 34.4 11.7 15.8 36.4 36.4 15 15 20.1 95-queue 0.5 20.3 9.8 16.7 - 12.5 - 2.4 - - Ave queue 0.3 11.1 5 8.9 - 6.5 - 1.2 - - Delay 10.9 28.2 34.8 29 30.1 36.4 36.4 15 15 29.5 95-queue 0.5 22.6 9.8 23.8 - 12.5 - 2.4 - - Ave queue 0.3 12.5 5 13.3 - 6.5 - 1.2 - - What are the 3 critical movements? EB thru, WB left, NB approach EB 27.9 21.2 27.9 What are the effects of uncertainty? EB and NB approaches see a larger amount of delay Findings and Additional Observations We’ve seen that to allow for these pedestrian times, the cycle length gets longer and the vehicular delays get larger. Pedestrian push-buttons are particularly valuable where the pedestrian volumes are light. On the cycles when the pedestrian timings aren’t invoked, the delays will be shorter and the signal will be more responsive to the vehicular flows. For lane utilization, we’ve seen what effect it can have on estimates of delays and queue lengths. We’ve seen that as the lane utilization gets poorer (i.e., more traffic in just one lane), delays and queue lengths increase. Not accounting for lane utilization, and using the defaults, can lead to overly optimistic assessments of intersection performance.