Grade separated, or raised, bicycle lanes provide separation and protection from car travel. The raised profile, sometimes shared with sidewalks, offers additional separation from vehicle traffic.
Benefits & Problems Addressed
Reduced impacts: Reduced impacts include "dooring" (bicyclists are hit as drivers swing open car doors).
Increased ridership: There is evidence segregated lanes of all types attract riders who otherwise will not bicycle on roads with no separation.
Construction costs: With new roadway construction a raised cycle track can be less expensive to construct than a wide or buffered bicycle lane.
Tips & Techniques
Best candidate roadways: (1) higher speed streets with few driveways and cross streets; (2) streets where conflicts at intersections can be mitigated using parking lane setbacks, signage/marking,/signalization; (3) curvy roadways where cars can drift into at-grade lanes; (4) streets with high bicycle volumes (or potential to attract riders is high).
Typical design features: (1) Before-and-After Ridership studies, (2) Vehicle speed/volume thresholds for determining whether a separated bike lane is appropriate, (3) Width requirements based on bike travel volumes, (4) Width requirements/dimensions for separated bike lanes based on bicycle volume, (5) Intersection Approach - guidance for separated bike lane treatments at intersections, (6) Separated bike lane construction including materials, curb height from the roadway and storm water management, (7) Signage., in particular where bikes and pedestrian facilities are on the same plane.
Intersections: Intersection design need special care as bicyclists will need to change from elevated path to roadway via a curb cut or apron. Special practices include: (1) In downhill situations, separated bike lanes should merge with vehicle traffic prior to intersections; (2) Signal timing to give advance green time for bicycles and phasing to separate right-turning auto travel and through cyclists; (3)
Bus stops: Bus stops should be positioned between the roadway and separated bike lanes.
Maintenance considerations: Use materials where pothole repair is limited or can be carried out flush with the lane. Consider street sweeping and snow removal equipment needs.
Hot Buttons: Conflicts with pedestrians are higher if lanes are on same plane as sidewalk. Consider ADA requirements and placement of street furniture, street trees, kiosks and other amenities encroaching into sidewalks/lanes. Retrofit can be expensive and drivers & businesses can complain about loss of a car travel lane.
Raised Cycle Tracks: NACTO (National Association of City Transportation Officials) Urban Bikeway Design Guide:
Image Credits: Flickr/Payton Chung