Agenda - Council - 04/14/2020 - Laserfiche WebLink

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4.2. b Alternative Reconstruction Method To meet the required 9-ton design strength, the SFDR method requires a 10-inch section including 4-inches of new bituminous over 6-inches of SFDR. Alternatively, this design strength can be achieved using a 14-inch section including 4-inches of new bituminous over 10-inches of class 5 aggregate base. However, the downsides of using the 14-inch section are that project costs are estimated to be 13-percent higher than the SFDR method since 6-inches of subgrade excavation would be required, and material would need to be hauled off -site. All of the reclaim material would also have to be stockpiled, and it is estimated an additional 5,800 CY of class 5 aggregate base would be required. Additionally, excavating below existing subgrade would result in more impacts to the existing ditches. For these reasons, Staff is recommending the SFDR method. 4.2. c Safety Improvements 4.2. c.lVariolite Street and 161st Avenue Pedestrian Crossing The City has received several requests in recent years to improve pedestrian safety at the intersection of Variolite Street and 161st Avenue, resulting in a review of pedestrian safety concerns at this intersection by the Public Works Committee on May 16, 2017. At that time, based on the geometries of the site and the minimal amount of pedestrians crossing Variolite Street, improvements were not justified. It was recommended to take another look at this location when Variolite Street came up for reconstruction, and to consider possible roadway improvements to alleviate the geometric concerns of the site. As part of this feasibility study, Staff conducted a pedestrian crossing study at the aforementioned intersection. This study was completed following both MnDOT and FHWA safety guidelines as well as the Highway Capacity Manual Level of Service Analysis at Uncontrolled Crossing Locations. As in 2017, the recommendations of all these sources is to not improve the site with marked crossing or signage alone, but to perform traffic calming of the road corridor. Staff has determined the most effective method of traffic calming is to reduce vehicle speeds to 40 mph by constraining lane and shoulder widths to meet MSA standards for a 40 mph rural road, in addition to adding a concrete pedestrian refuge island at 161st Avenue. A figure of the proposed pedestrian crosswalk improvements is included in Appendix A. Staff therefore proposes to reduce drive lane widths to 11-feet, and shoulder widths to 6-feet, south of 163rd Lane to meet MSA design standards for a 40 mph rural road. The installation of a concrete pedestrian refuge island on the north leg of Variolite Street at 161st Avenue will allow pedestrians to focus on one lane of traffic, safely cross that lane, then wait within the raised median island until an acceptable gap is available to safely finish crossing the next lane of traffic. An additional benefit is the shortened crossing times. ADA compliant pedestrian landings are proposed for all crosswalks at this intersection. Staff met with MnDOT State Aid Staff to discuss the City's proposed design. State Aid Staff agreed that a raised concrete pedestrian refuge island likely provided the greatest safety benefit, but suggested considering mini -roundabouts instead. Staff explored the mini -roundabout option, but due to right-of-way constraints, this option is not considered feasible at this time. Feasibility Report Variolite Street Reconstruction City of Ramsey Project No. 20-01 7