Agenda - Council - 08/08/2016 - Laserfiche WebLink

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31 LOCAL STATE-AID ROUTE STANDARDS,FINANCING 8820.9920 New or reconstruction projects for rural and suburban undivided roadways must meet or exceed the minimum dimensions indicated in the following design chart. Pro- Lane Shoulder In- Clear Design Sur- Structural Bridges jected Width Width slope Zone (c) Speed facing Design to ADT (b) (d) Strength Remain (a) (e) Width Curb to Curb rise: feet feet run feet mph tons feet 0-49 11 1 1:3 7 30-60 Agg. 22 50-149 11 3 1:4 9 40-60 Agg. 22 7-ton/ Agg./ 10-ton 150-299 12 4 1:4 15 40-60 Paved Staged(g) 28 10-ton 300-749 12 4 1:4 15 40-60 Paved Staged(g) 28 750- 10-ton 1499 12 4 1:4 25 40-60 Paved Staged(g) 28 1500 and over 12 6(f) 1:4 30 40-60 Paved 10 30 Engineering judgment should be used to choose a lane-width, on-road bicycle facil- ity, or shoulder-width dimension other than the widths indicated in the chart for road- ways. Factors to consider include safety, speed, population/land use, benefit/cost analy- sis,traffic mix,peak hourly traffic,farm equipment,environmental impacts,terrain limita- tions,bicycle traffic, pedestrian traffic, on-street parking, intersection and driveway spac- ing, rights-of-way constraints, vehicle turn lane configuration, sight distance, sight lines, bus routes,other nonmotorized uses,functional classification,or other factors. Dimensions less than those indicated in the chart require a variance in accordance with parts 8820.3300 and 8820.3400. For rural divided roadways,use the geometric design standards of the Mn/DOT Road Design Manual,with a minimum ten tons structural design and minimum 40 mph design speed. (a)Use the existing traffic for highways not on the state-aid system. (b)Applies to slope within the clear zone only. (c) Culverts with less than 30-inch vertical height allowed without protection in the clear zone. Guardrail is required to be installed at all bridges where the design speed exceeds 40 mph,and either the existing ADT exceeds 400 or the bridge clear width is less than the sum of the lane and shoulder widths. Mailbox supports must be in accordance with chapter 8818. For roadways in suburban areas as defined in part 8820.0200, the clear zone may be reduced to a width of ten feet for projected ADT under 1,000 and to 20 feet for projected ADT of 1,000 or over. Wherever the legal posted speed limit is 40 mph or less, the clear zone may be reduced to a width of ten feet. (d) Subject to terrain. In suburban areas,the minimum design speed may be equal to the current legal posted speed where the legal posted speed is 30 mph or greater.