PRSR 10-12-1994 - Laserfiche WebLink

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Feb. 8, 1983 BIKEWAYS -21- • 1. On road The structural section of an off-road bikeway should be designed in the same manner as a highway, with con- Bicycle travel shall be in the same direction as sideration given to the quality of the subsoil and the adjacent motor vehicle traffic in compliance with the anticipated loads the bikeway will experience. Principal uniform vehicle code. A minimum width and lateral loads will normally be from maintenance and emergency clearance will depend on the location of the lane within the vehicles. These vehicles should be restricted to less than 4 roadway and parking conditions.The bikeway design tables or 5 ton axle loads, especially in the spring. provide widths for various roadway conditions. The gutter section of a curb and gutter should normally not be con- Bituminous surfacing is recommended. Figure F sidered as a part of the bicycle lane since the joint between provides typical surfacing designs for full depth bitumin• the gutter and roadway surface can be very hazardous to a ous and aggregate base sections. cyclist. 2. Off-road Bikeways FULL DEPTH 2" to 6" 1 The cross section of an off-road bikeway can be :;.....:::..::...:.:.:..:;:•:•:•; determined from the widths and clearances presented. �:;`��••`�:�`.Fi;2;'}:�ti `\+ \`�: The minimum widths based on the number of lanes are _.* ��•. �- as follows: Number of Minimum Paved Width AGGREGATE BASE Lanes feet 1-1/2,, : 3 :;: 1 4.0 —�— .................•.• 2 8.0 3" to7" 4 In addition, a minimum two foot graded area on each side i r�:ti'' "' '`', •�' ' • of the bikeway should be provided adjacent to the paved "�'�^ ` ,{�r 'j; surface. See Figure E on page 4. It should be emphasized • �-� that the minimum width and clearances are for bicycle needs and are not sufficient to accommodate maintenance 1. Spec. 2331 Wearing Course (Full Depth) and emergency vehicles (pickups, mowers, ambulances, 2. Compacted Subgrade etc.). Accordingly, the minimums may have to be adjusted, 3. Spec. 2331 Wearing Course as necessary, to provide for these considerations. In ad- dition to the widths provided above, additional widths 4. Class 5 Aggregate Base should be provided for sharp curves and where steeper 5. Compacted Subgrade grades are necessary. On steep grades, additional width is necessary due to increased speed and needed room for FIGURE F maneuverability. On sharp curves, less than 100 foot radius, additional width may be needed due to bicycle lean. The TYPICAL OFF-ROAD DESIGN SECTIONS following values are recommended for widening: • Radius Additional Paved Width The lighter sections should be used only in granular feet feet subsoils. 0-25 4 – Topsoils and other organic soils should be removed. 25-50 3 50-75 2 -- A 1 foot subcut should be provided for uniformity 75-100 1 100+ 0 and compaction. } – Granular subgrades may require a minimum 1 inch. G. STRUCTURAL SECTION Class 1 stabilizing aggregate, especially in the full depth • bituminous section. For bike routes and lanes the inplace surfaced struc- – Consideration should be given to increasing the asphalt •ture is normally adequate. When a roadway with unpaved content by 1 to 2% to provide increased pavement life. shoulder is to be surfaced for a bike lane, standard Mn/DOT shoulder designs should be specified. Subgrade and surfacing recommendation should be requested from a Materials or Soils Engineer.