Agenda - Public Works Committee - 05/16/2017

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Public Works Committee Meeting Date: 05/16/2017 Submitted For: Grant Riemer, Engineering/Public Works By: Grant Riemer, Engineering/Public Works 5. 1. Title: Review Pedestrian Safety Concerns at Variolite St and 161st Ave Purpose/Background: At the April 18th Public Works Committee meeting staff was directed to gather traffic data and other pertinent information regarding pedestrian safety at the intersection of Variolite St/ 161st Ave. Staff has compiled traffic counts, speed data, stopping sight distances for vehicles, pedestrian sight distances, accident reports and LOS (Level of Service) ratings for the intersection. Variolite St has a posted speed limit of 50 mph with a restricted sight line view to the north of 161st because of a hill. Information gathered from the police speed trailer over two days shows the 85 percentile speed is 64.91 mph. The speed limit is commonly set at or below the 85th percentile operating speed (being the speed which no more than 15% of traffic is exceeding) and in the US is typically set 8 to 12 mph 13 to 19 km/h) below that speed. Timeframe: 15-20 minutes Observations/Alternatives: The results of information gathered are as follows: Traffic Counts (traffic counts are based on two 24 hour counts and then averaged) Variolite St south of 161st Ave =1767 cars Variolite St north of 161st Ave=1817 cars 161st Ave west of Variolite St=674 cars 161st Ave east of Variolite St= 522 cars Crosswalk Width on Variolite St= 52 feet Level of Service Rating -A Average wait time is estimated at 4.3 seconds Clear sight line distance to the south of 161st Ave = 1810 feet Clear sight line distance to the north of 161st Ave =330 ft Required stopping distance at 50 mph = 424 feet Required stopping distance at 65 mph = 644 feet Pedestrians crossing Variolite St in 91 hour time span -8 Accident Reports = 1 2/20/2012 car slid off the road due to slippery conditions This crossing location has several factors that make it not suitable for a pedestrian crosswalk at this time. The first and the most significant negative feature would be the lack of sight line distance to the north. The sight line distance to the north is approximately 330 feet. A motorist traveling at 50 mph requires 424 feet to react to a pedestrian in the crosswalk and to begin braking to avoid a collision. The next negative factor would be the speed on Variolite. Through our data collection we found that the actual speed driven by 85% of the motorists on Variolite is 64.9 mph. At that speed the the braking distance required would increase to 644 feet. That's almost twice the the sight line distance available to the north. The last point would be pedestrian volume at the intersection. MnDot recommends