Agenda - Parks and Recreation Commission - 01/12/1995

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m m Feb. 8, 1983 BIKEWAYS -21- m m m m m m Im m m m m m m m m m 1. Ck~ road Bicycle travel si!all be in the same direction as adjacent motor vehicle itraffic in compliance with the uniform vehicle code. ~A minimum width and lateral clearance will depend on ~e location of the lane within the roadway and parking eon$itions. The bikeway design tables provide widths for variou]; roadway conditions. The gutter section of a curb and guiter should normally not be con- sidered as a part of the b~c~_cle lane sb,ce the joint between the clutter and roadway mirface can be very hazardous to a cychst. 2. Off-road Bikeways The cro~ secdo~ of an off-road bikeway can be determined from the widths and clearances presented. The m/nimum widths b~ ~ed on the number of lanes are as follows: Number of { i Iv~knum Paved Width Lanes feet 1 : 4.0 2 : 8.0 In addition, a raihimum t~vo foot graded area on each !fide of the bikeway should b~. provided adjacent to the paved surface. See Figure E on l~age 27. It should be emphasized that the minimum widtli and clearances are for bicycle needs and are not suffici~,t to accommodate maintenance and emergency vehicles !(pickups, mowers, ambulances, etc.). Accordingly, the mihimums may have to be.adjusted, as necessary, to provide ;'.for these considerations. In ad- dition to the widths prbvided above, additional widths should be provided for Isharp curves and where steeper grades are necessary. On~teep grades, additional width is necessary due to increa~d speed and needed room for maneuverability. On shar~curves, less than 100 foot radius, additional width may be ineeded due to bicycle lean. The following values are recommended for widening: Radius !Additional Paved Width fee t feet 0-25 4 25-50 3 50-75 -2 75-100 1 100- 0 G. STRUCTURAL SECTION For bike routes and. lanes the inplace surfaced struc. ture is normally adequate. When a roadway with unpaved shoulder is to be surfaced (or a bike lane, standard Mn/DOT shoulder designs should he'specified. The structural section of an off-road bikeway should be designed in the same manner as a highway, with' con. sideration given to the quality of the subsoil and the anticipated loads the bikeway will experience. PrmcipaJ loads w/Il normally be from maintenance and emergency vehicles. These vehicles should be restricted to less than 4 or 5 ton axle loads, especially in the spring. Bituminous surfacing is recommended. Figure F provides typical surfacing designs for full depth bitumin- cms and aggregate base sections. 2" to 6" & FUI. L DEFTH 1-1/2" 3" to 7" AGGREGATE BASE ['~:kxg.9'~j .',_.-.-,.-,...- · a',-,----,-~ ---,--' 1. Spec. 2331 Wearing Course (Full Depth) 2. Compacted SubcFade 3. Spec. 2331 Wearing Cout~ 4. CI~-, 5/k/qregate Base 5. Compacted Subgrade FIGURE F TYPICAL OFF.ROAD DESIGN SECTIONS - The lighter sections should be used only in granular subsoils. - Topsoils and other organic soils should be removed. -A 1 foot subcut should be provided for uniformity and compaction. Granular subgrades may require a minimum 1 inch Class 1 stabilizing aggregate, especially in the full depth bituminous section. - Consideration should be given to increasing the asphalt content by 1 to 2% to provide increased pavement life. Subgrade and surfacing recommendation should be requested from a Materials or Soils Engineer.