2007-11-28 CC Packet - Laserfiche WebLink

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Jane Rose Jack Corkle October 16, 2007 Page 3 · In reviewing the CSAH 14 Study that was completed by SRF, the intersection of CSAH 14/20th Avenue was found to operate at an unacceptable LOS E during the p.m. peak hour under all-way stop control. The Centerville EA W traffic analysis documented that this intersection is operating at LOS C during this time period. In comparing the intersection turning movements, the volumes increased during both the a.m. and p.m. peak periods between 2004 and 2007, which would indicate similar or worse operations. Due to the discrepancy, analysis was completed for this intersection with the current traffic volumes and all-way stop control using the Highway Capacity Software and Synchro/SimTraffic software package. Based on this analysis, we found this intersection to operate at an overall unacceptable LOS E during the p.m. peak hour. This intersection should be checked to ensure that adequate capacity is provided for existing and future conditions. · The 2012 operations analysis assumed upgrades to the CSAH 14 corridor that are scheduled to be completed in 2009, including signalization of CSAH 14/20th Avenue and widening CSAH 14 to improve the 90-degree curve just west of the intersection with CSAH 21 (Centerville Road). No additional improvements are recommended. Based on the CSAH 14 roadway design plans that will be constructed next year, the southbound approach of 20th Avenue at CSAH 14 should consist of dual left-turn lanes, one through lane, and a shared through/right-turn lane. It appears that this study analyzed this approach with dual left-turns lanes, one through lane, and a right-turn lane. Although this will not significantly impact operations, the correct future geometrics should be noted in the study. In addition, the geometrics shown on this approach are not consistent throughout the report for 2030 conditions. Based on the operations analysis shown in the appendix of the report, dual southbound left-turn lanes were included. · For 2030 conditions, the roadway upgrades identified for 2012 conditions are assumed as a baseline. However, the improvements were recommended to be modified to improve safety. The modified improvement includes the installation of a northbound left-turn lane instead of a right-turn lane at the intersection of CSAH 14/Centerville Road. In addition, installation of a southbound left-turn lane is recommended at this intersection, with future signalization, to align the left-turn lanes on the north and south approaches. Installation of a southbound right-turn lane at CSAH 14/Progress Road is also recommended. Based on our analysis, the suggested modifications to the roadway geometrics will not change the overall intersections operations, and it may provide some additional safety for the intersections and flexibility in providing future left-turn phasing. In regards to the southbound right-turn lane at Progress Road/CSAH 14, this improvement does not significantly improve operations or safety, based on our review. If the right-of-way is available to construct a right-turn lane on this approach, it would provide some delay reduction to that individual movement.