This post begins an ongoing blog series highlighting various complete street elements, their benefits, and use in Michigan communities. Check back often to catch future posts, and keep a lookout for these elements in your community!
What are Sharrows? Shared-lane markings, often called sharrows, indicate proper lateral positioning for bicyclists riding on roadways. The sharrow design consists of a bicycle symbol with a double set of chevrons, pointing in the direction a bicyclist should ride.Why Use Sharrows? Sharrows help bicyclists determine where they should ride on the road. According to the Michigan Manual of Uniform Traffic Control Devices (MMUTCD), shared-lane markings create safer road conditions for cyclists by:
- Assisting bicyclists with lateral positioning in a shared lane with on-street parallel parking in order to reduce the chance f a bicyclist’s impacting the open door of a parked vehicle,
- Assisting bicyclists with lateral positioning in lanes that are too narrow for a motor vehicle and a bicycle to travel side by side within the same traffic lane,
- Alerting road users of the lateral location bicyclists are likely to occupy within the traveled way,
- Encouraging safe passing of bicyclists by motorists, and
- Reducing the incidence of wrong-way bicycling.
When to Use Sharrows: Sharrows can be found on roads under 35 mph. Proper placement of sharrows (per MMUTCD) is immediately after intersections, and no more than 250 feet apart thereafter. Some factors that influence lateral placement of sharrows on roads are road width, changes in road width, and the presence or absence of on-street parking. Sharrows can also be used to tell cyclists where to ride when bike lanes stop and start again.
Safety Benefits: Data suggest that sharrows are effective traffic safety measures for cyclists. A 2010 Federal Highway Administration review found that a high percentage of cyclists rode over sharrows, increasing their visibility and protecting them from collisions with parked-car doors. Cars also afforded cyclists more riding room between them and curbs or parked cars. A 2011 Los Angeles DOT study found that sharrows significantly increase vehicle passing distance, and for cars that do not pass, drivers typically exhibited less aggressive behavior and tailgated less. A 2004 San Francisco study found that cars gave cyclists 3-4 more inches of riding room when sharrows were present. Sharrows were also associated with a 25-35% decrease in sidewalk riders, possibly indicating a greater comfort level with riding on a sharrow-marked road.
What Drivers Should Know: While it may be tempting to think that the main purpose of sharrows is to denote a shared-space between bicyclists and motorists, sharrows are more about where cyclists should ride on the road—bicycles and vehicles must always share the road in Michigan, regardless of markings. Sharrows do tell motorists where bicyclists are likely to ride, and where bicyclists may be reentering the roadway where bike lanes end.
Cost Considerations: Using sharrows is a cost effective way for municipalities to increase roadway safety. The treatment does not require road widening or repaving, and applying the marking is relatively inexpensive. Material costs for shared-lane markings are around $150 per pavement marking, and around $200-250 depending on the application method. Per the MMUTCD, sharrows are used about every 250 feet and after each intersection. On a two way street, this means around 40 markings per mile at a cost of $6,000. Based on block length and intersection location, though, it is unlikely that a community would need this many sharrows, so costs would likely be lower.
Sharrows are low-hanging fruit that can make a significant and immediate impact. Michigan communities have taken notice, and sharrows are becoming more common as complete streets policies have gained steam. Flint holds the distinction being the first Michigan community to have sharrows, and Michigan State University, Grand Rapids, Royal Oak, Elk Rapids and many others have followed suit.
Have Sharrow in your community? Let us know.
Check out these resources for more information.
Next Topic: Pedestrian Hybrid Beacons Explained