02-19-2008 Agenda - Laserfiche WebLink

- 9 - FINDINGS AND RESULTS Table 1 Roundabout Volume to Capacity Results for Year 2015 and 2025 Volumes NB EB SB WB INTERSECTION APPROACH APPROACH APPROACH APPROACH A 2015 CR 17/52nd Ave I 1 1 1 M 2025 CR 17/52nd Ave 1/2- 1 1 1 P 2015 CR 17/52ndAve 1 I 1 1 M 2025 CR 17/52nd Ave I 1 1/2- 1 1 = Under Capacity for a Single-Lane Roundabout 2 = Under Capacity for a Double-Lane Roundabout, Over Capacity for a Single-Lane Roundabout 3 = Over Capacity for a Single-Lane and a Double-Lane Roundabout -Both locations are at the single-lane roundabout capacity threshold Results of the roundabout analysis at each approach are shown in Table 1. The intersection of CR 17/52nd Avenue will operate below the capacity threshold of a single-lane roundabout in the year 2015. However, in the year 2025, the northbound approach in the a.m. peak hour and the southbound approach in the p.m. peak hour are both near the capacity threshold for a single-lane roundabout approach. As the approach nears the capacity threshold, delays start to increase at the approach at an exponential rate as the volumes continue to increase. A single-lane roundabout at the intersection of CR 17/52nd Avenue would operate at an acceptable level of service in 2015, but may not operate at an acceptable level of service in 2025. In this situation, a two-lane roundabout would have to be considered at this location to accommodate the projected 2025 traffic volumes. If a northbound to eastbound right-turn by-pass was constructed, this would allow the northbound approach to operate below the threshold of a single-lane roundabout during the a.m. peak hour in year 2025. However, a southbound to westbound right-turn by-pass would not allow the southbound approach to operate below the threshold of a single-lane roundabout during the p.m. peak hour in year 2025. This would need to be a two-lane approach. Considering that only one approach needs to be two-lanes, it is not necessary to construct a full two-lane roundabout in year 2025, rather a multi-lane roundabout would be more appropriate.