What are Sharrows?
Sharrows are white pavement markings showing a bicycle symbol with two chevrons on top (MUTCD). Some mistake these lanes for dedicated bicycle lanes, but a bicycle lane is marked with a bicycle symbol and sometimes an additional diamond symbol. The diamond symbol indicates that it is a reserved lane.
When a street is too narrow to fit both a lane for bicyclists only, and too narrow for cars and bicycles to ride side-by-side, sharrows remind bicyclists and motorists that the lane must be shared.
Oliver Gajda, the former Manager of a Bicycle Program in San Francisco, is credited with inventing the term sharrow. It is supposed to be a combination of the two words share and arrow, even if the arrows look more like chevrons.
Bicyclist May Use the Full Lane
When necessary for safety, a bicyclist may ride in the middle of a travel lane. This is true even when no shared lane markings are painted on the pavement. A bicyclist should always keep a safe distance to parked cars. A suddenly opened door can hit a bicycle and cause serious injury.
Sharrows serve as a reminder. They guide a bicyclist toward the center of a lane.
What Motorists Must Know
Motorists must be aware that a shared lane marking means that bicyclists may use the full travel lane. When approaching a bicyclist, the motorist should slow down and keep a safe distance. The motorist should not attempt to pass in the same lane, unless it is safe to do so and there is enough room. In general, a motorist should wait for a safe opportunity to move entirely into an adjacent lane.
Sometimes, “Bicycles May Use Full Lane” signs maybe used along streets with sharrows.
Are Sharrows Effective?
Research indicate that shared lane markings increase operating space for bicyclists. But there are no studies suggesting that sharrows are effective in reducing bicycle accidents. A 2016 study in Chicago actually shows that areas with sharrows installed were much less effective at reducing injuries per year per commuter than areas with bike lanes or no infrastructure.
Manhattan photo by Jim Henderson