ROADWAY TUNNEL AND UNDERPASS
These are types of enclosed roadways
with access at both ends.
Design & Safety Issues to Consider:
- Absence of bicycle facility on approaches should not prevent bicycle accommodation within the tunnel/underpass
- Options include widening or eliminating existing sidewalks in tunnels
- Sidewalks in tunnels may act as barriers to prevent vehicles getting too close to the side or for emergency use
- Good lighting is important so that motorists can see and react to bicyclists
- Consider personal safety in tunnels
- Overhead clearance needs to be maintained throughout
- Unexpected ice patches can form from overhead drips
- Road hardware in tunnel pavement can be less visible and cause problems
- Provision of adequate width bike accommodations on both sides of roadway through tunnel
- Adequate vertical clearance
- Tunnel abutments clearly marked
- Road hardware and obstacles
RAILWAY AND LIGHT RAIL CROSSING
These are the intersections of a roadway
or a path with a railway line or tram line.
Design & Safety Issues to Consider:
- Railroad tracks that cross the route of a bike on an angle can cause steering difficulties for bicyclists
- Angle of track should be at least 60 degrees or better so bicyclist can safely cross
- Railroad crossing surfaces vary: concrete, rubber, asphalt, or timber
- Concrete provides the smoothest and least slippery riding surface
- Shared lane markings may be used to guide bicyclists to the best route and angle of crossing
- Angle of railroad track relative to path or bike travel
- Crossing surface and condition
- Width and depth of flange opening
- Signs and markings
BRIDGE AND CULVERT
These are structures erected over a
depression or an obstruction such as
water or a roadway.
Design & Safety Issues to Consider:
- Bridges can be a significant barrier to bicycling due to lack of dedicated space
- Bridges are often narrower than approach roads
- Absence of bicycle facility on approach should not prevent bicycle accommodation on bridge
- Sidewalks may be acceptable bicycle facility for long narrow bridge
- Consideration should be given to shared-use path with concrete barrier on both sides of bridge
- Where bridge is too narrow, it may be possible to add cantilever structure to accommodate bikes
- Side rail heights: 42 inches min.
- Side rail heights with higher bicycle speed: 48 inches
- Full pavement width maintained
- Provision of bike accommodations on both sides of roadway
- Bridge deck surface and joints
- Road hardware on bridge deck
- Signs and markings
Contents | Next section
Guide for Reviewing Public Road Design and Bicycling Accommodations for Virginia Bicycling Advocates