Shared Lane Pavement Markings

Biker on Albany Street with Shared Lane "Sharrow" markings

What Are Shared Lane Pavement Markings?

They are road markings to indicate that motorists and cyclists must share the travel lane. They are sometimes referred to as “sharrows.”

The purpose of the markings is to create improved conditions for bicycling, by clarifying where cyclists are expected to ride and to notify motorists to expect cyclists on the road. In the absence of bicycle lanes, motorists often neglect to share the travel lanes safely with cyclists, and cyclists feel compelled to ride closer to parked cars. If somebody were to open a car door as a cyclist passed the cyclist could get “doored.” Also, when cyclists stay to the far right in narrow travel lanes, passing motorists often pass too closely to the cyclists. This is not only unnerving for the cyclist, but leaves little margin for error.

Why Not Just Stripe Bicycle Lanes?

Shared markings are typically used when there isn’t enough room on the street for bicycle lanes or cycle tracks, which are still the best treatments for creating safe and comfortable conditions for bicycling on busy streets. We will consider using shared lane pavement markings only after evaluating all possibilities for preferred facilities.

As a Cyclist, What Should I Do in the Presence of These Markings?

The markings are placed approximately where cyclists should be riding. Cyclists should stay in the middle or to the left of the markings.

As a Motorist, What Should I Do in the Presence of the Shared Pavement Markings?

Slow down and drive carefully. Because the travel lane is too narrow for safe side-by-side travel by motorists and cyclists, motorists should slow down and either wait for the cyclist to turn off the roadway, or wait until s/he can move into an adjacent travel lane.

Do the Shared Lane Markings Work?

Studies have shown that in the presence of the markings cyclists moved further away from parked cars and passing motorists moved further away from cyclists than in the absence of them. Shared lane markings are not a substitute for bike lanes but are a benefit on narrower busy streets.

For More Information

For more information about bicycling in Cambridge, please contact Cara Seiderman,, at 617/349-4629.