Agenda - Council - 04/13/2021 - Laserfiche WebLink

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4Spack SOLUTIONS Technical Memorandum From: Jonah Finkelstein, PE Date: 1/7/2021 Re: Memorandum 1— Riverstone South Residential Development Spack Solutions completed a Traffic Impact Study for the Riverstone South Residential Development in December of 2020. Since the completion of that study, the City has requested additional delay documentation for the mitigated future scenario and its impact on the Highway 10 ramp intersections. This document presents those findings Vehicular Mitigation Analysis As mentioned in the original report, most of the study intersections and all corridors will operate acceptably throughout the study scenarios. However, the proposed side street stop controlled intersection of Hwy 10/Riverdale Drive begins to see queues that extend above five vehicles. Investigation into the queues at this intersection revealed that in the no -build and build scenarios delays begin to reach excessive levels for the northbound left turning movements. This movement will experience delays up to: • Four minutes in the 2022 no -build scenario • 21 minutes in the 2040 no -build scenario • 12 minutes in the 2022 build scenario • Over an hour in the 2040 build scenarios To alleviate these delay issues a 3/4-access, eliminating the northbound left turning movement from the intersection, was recommended. The impacted vehicles at this intersection would now be required to travel east on Riverdale Drive to the northern Highway 10 ramp intersection, where they can continue westbound on Highway 10. Chart 1 and Chart 2 present the delay and queueing results at the Highway 10 ramps under this mitigated scenario for the 2040 forecast year. The 2040 forecast year was analyzed because mitigation that works under the extended forecast scenario will also work under the shorter term 2022 growth scenario.