Shared Lane Markings, (SLMs), or “sharrows,” are road markings used to indicate a shared lane environment for bicycles and automobiles. Among other benefits sharrows reinforce the legitimacy of bicycle traffic on the street and recommend proper positioning for people on bicycles. More specifically, help bicyclists position themselves safely in lanes too narrow for a motor vehicle and a bicycle to comfortably travel side by side within the same traffic lane. Sharrows encourage safe passing, (at a reasonable speed at least three feet to the left of bicyclists), by motorists. Virginia law was amended in March 2015 to allow motorists to cross the double yellow lines in order to safely pass bicyclists.
When bicycling on a street with sharrows, bicyclists should use the full lane and position themselves at the apex of the chevron arrows in order to avoid the “door zone,” (space needed for parked vehicles to open doors), or other roadside hazards.
Other benefits of sharrows:
Alerts motor vehicle drivers to the presence of bicyclists.
Provides a element along bike routes.
May reduce the incidence of sidewalk riding and wrong-way bicycling
Sharrows in the Bike Master Plan (193kb pdf)