Good roads for cycling are those that are designed, maintained, and policed with cyclists in mind. In the language of engineering, the bicycle should be a design vehicle. That is, road design should account for the operating requirements of bicycling. Since roads are designed to accommodate wider, taller, and faster design vehicles, most roads will also accommodate cycling.
|Motorists generally leave plenty of room when passing cyclists, especially when there is no line separating them. Note that motor traffic has kept the entire width to the left of the white edge line clear of sand and debris (location: West Roxbury Parkway, Boston, Massachusetts, USA).|
There are a few special considerations for cyclists:
Surface Quality Roads should be of smooth asphalt. Concrete is less desirable. Roads should be maintained to be free of holes and bumps.
Holes Slots parallel to the road, such as drain grates, can cause serious falls. These defects should be fixed.
Ridges Ridges parallel to the roadway can cause diverting falls. These types of hazards include railroad and especially streetcar tracks, seams, bridge expansion joints, and undulations.
Metal Metal is extremely slippery when wet. Metal deck bridges should have a concrete section. Metal plates installed to cover road works should be out of the way of cyclist’s normal route. At the least, warning signs should be installed.
Traffic Light Activators Wherever an intersection approach uses traffic detectors, there should be a detector loop designed and tested to be sensitive to the amount of metal in a bicycle wheel and located at all the locations where bicyclists may lawfully wait for the light to change. For more information, see Alan Wachtel
Lane Width On a road which carries a significant volume of traffic, the right hand lane should be wide enough for bicyclists and motorists to share side by side. The minimum is 14 ft (4.5 m). This sharable space includes any smooth paved shoulder. If there is on-street parking, the total width of the right-most travel lane and parking lane combined should be 24 ft (preferred), 22 ft (minimum). If it is impossible to provide these lane widths, a Share the Roads reminder sign should be posted, since safe bicyclists will be traveling in the middle of lanes that are too narrow to share side by side with motorists.
Traffic Signal Timing There should be an all-red phase sufficiently long for bicyclists to clear the intersection, even if they enter on the end of the yellow. For more information, see John Forester on Traffic Signal Clearance Time for Cyclists. See also Axel Wilke, Cyclists at Wide Intersections: All-Red Time Extension on Demand (pdf).