Shared Lane Marking
A shared lane marking, also known as a sharrow is a lane marking depicting a bicycle intended to inform road users where bicycles are supposed to ride within the lane.
Common reasons for their use include
- Communicating to drivers that cyclists have a right to use the road
- Encouraging cyclists to use a specific part of the lane, such as the edge or center (taking the lane).
Recommended Use and Limitations[edit | edit source]
Shared lane markings can be helpful as part of a Bike Boulevard or a shared space by assisting in communicating where bicycles are meant to ride within the lane.[1][2] See the articles on bike boulevards and shared spaces for specific guidance on where and when to apply shared lane markings.
Shared lane markings have historically been used on roadways with high traffic volumes or high speeds as a form of bikeway. This solution is no longer considered acceptable by most agencies, since it is generally not accessible to riders of all ages and abilities (AA&A).
According to the 2025 NACTO Urban Bikeway Design Manual, roadways where bikes and motor vehicles share a lane should have an AADT of less than 2000 and a target speed of 20 mph or lower, as part of a bike boulevard or shared space. The guide explicitly states that shared lane markings on their own are not sufficient to create an AA&A bikeway.
The 2024 AASHTO Guide for the Development of Bicycle Facilities states that sharrows should only be used as part of a bicycle boulevard or shared space. "By themselves, shared lane markings are not considered a bikeway because they do not change the geometric or operational conditions of the roadway to improve comfort and safety for bicyclists." {TODO cite 9.3.3. of bike guide)
TODO crow manual
TODO summary.