Revisiting the two-way sharrows

Standard MUTCD sharrow
Standard MUTCD sharrow

Sharrows (also known as “shared lane markings”) are on-street pavement markings that are intended to remind people in cars to expect people on bikes on a street. They help to indicate bike routes, and they are useful to help people on bikes position themselves in the road.

Commercial Street, the main drag through town, is one-way for cars and two-way for bikes. It’s very narrow (about 22 feet, and narrower in places), has a narrow sidewalk of about 36″ on one side, with a parking lane next to the sidewalk for most of the street. The speed limit is typically signed 15 MPH.

Right now, the only indication that this street is two-way for bikes is a series of small green signs that are posted where cars enter from other streets.

Two-way bike traffic sign
Two-way bike traffic sign

Let’s try some sharrows

There was a brief experiment with a two-way sharrow on Commercial street back in 2012. It was developed by Daniel Alexander, a transportation scholar who was working with the Cape Cod National Seashore.

The Commercial Street sharrows looked something like this:2012 Commercial St sharrows

Feedback on this trial was sparse, but the little bit that’s documented in the Board of Selectmen meetings indicates that they were thought to be too small to be noticed (they were only 10″ wide by 24″ tall, where a standard sharrow is 40″ wide by 112″ tall). When the street was repaved the sharrows weren’t repainted.

Let’s try this again

I put together this mock-up of a two-way sharrow concept. It’s just the standard sharrow with added chevrons placed below the bicycle icon. It’s simple, gets the point across, could be flipped to have the bike heading in either direction, and it’s big enough to be noticed.

Two-way sharrow concept for Commercial St.
Two-way sharrow concept for Commercial St.

These could be painted in the middle of the travel lane on Commercial Street. It would help indicate to people in cars that they should expect bikes in both directions on the street, it would encourage people on bikes to ride in the middle of the travel lane, and it would help alert people on foot (who often walk in the middle of the street) to expect bikes in both directions.

Along with some additional signage changes, this could certainly help communicate to road users that they should expect two-way bike traffic and improve safety on Commercial Street.


MUTCD bike marking specifications:

NACTO sharrow guidance:

Bicycle Committee minutes, August 8, 2012. Discussion of feedback on sharrow trial:

Board of Selectmen minutes, September 12, 2011. Discussion of Commercial St. Sharrow Project:

Sharrow “flower” in Portland, OR:

When should streets use sharrows, painted lanes and separation?

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