Effectiveness of Sharrows

Michael Lehto at The Boondock Blogs offers a valuable critique of Cleveland Heights’ new sharrows. He writes,

I’m conflicted about the sharrow. I like what it represents: a community trying to do more for cyclists. But does it really communicate a message any differently than the old signage? Will I be safer now that this sign is painted on the road? Certainly it’s new, so it might attract drivers’ attentions for a while. But clearly it has the capacity to blend into the scenery out of sheer familiarity like so many other things. Moreover the painted emblems will no doubt fade over time, and what happens when the side of the street is covered with snow?

The subtler message of the sharrow may be more important: we’re trying. The real goal for the city, as outlined by a recent review of Cleveland Heights by the League of American Bicyclists (which awarded the city an “honorable mention” for its efforts at becoming a bike-friendly community), is for widened shoulders and bike-safe routes to schools, among other things. We won’t get there overnight though. Even in a city that prides itself on its progressively urban green culture, there are plenty of detractors… so things have to happen one step at a time.

Although empirical studies on the effectiveness of sharrows cannot addresses all of Lehto’s concern, there is research that shows that sharrows, when properly installed, do have a positive effect on cyclist’s safety.

San Francisco, 2004

The city of San Francisco and the San Francisco Bicycle Coalition conducted a study in 2004 on the effectiveness of three different types of sharrows: 1) a “bike in house” marking, 2) a “bike and separate arrow” marking, and 3) the “bike and chevron” marking, the kind Cleveland Heights installed this October. You can download the research article here. Their research found that sharrows “significantly improved both motorists’ and cyclists’ position in the roadway […] The markings also reduced sidewalk and wrong-way riding.” Here are the highlights of the study:

• Sharrows increased the distance of cyclists to parked cars by 8 inches. Cleveland Heights has decided not to install sharrows on Euclid Heights Boulevard where there on-street parking, since our lanes are too narrow to allow sharrows to be installed in a manner that would encourage cyclists to give safe passing distance.
• This is important: Sharrows caused an increase of over 2 feet in the distance between cyclists and passing vehicles.
• Sharrows significantly reduced the number of sidewalk riders by 35%.
• Sharrows significantly reduced the number of wrong-way riders by 80%.
• When surveyed, bicyclists felt the markings were a step in the right direction and felt that the markings increased their sense of safety. However, the intended message of the markings was not fully understood. This could be remedied through a public information campaign. The CHBC intends to work with the city of Cleveland Heights to educate the public on sharrows and their use. Keep an eye out for commercials on public TV, and an article we’ll be publishing in the Heights Observer.

The report concludes that sharrows do have a significant positive effect on both cyclists and motorists behavior, positions, and safety. If you have the time, download the report to take a look of all the findings which couldn’t be squeezed into this post.

Needless, San Francisco doesn’t have the same winter weather patterns as Cleveland Heights, so this study doesn’t address Lehto’s concerns about snow covering the sharrows. Nor does it measure the effectiveness of sharrows on motorists and bicyclists behavior over time. But it does offer empirical data that can help us understand the strengths and weaknesses of sharrows. For instance, despite the positive effects of sharrows, the research does show that the markings have neither a positive nor negative effect on motorists aggression.

Fortunately, there is strong evidence from communities like Portland, Oregon that show there is a strong positive correlation between infrastructure and cyclists. The more sharrows, bike lanes, and other amenities, the more cyclists on the road. There’s also strong evidence that shows that the more cyclists are on the roads, the safer they are from accidents with motorists.

In addition to Lehto’s level-headed critique, the Cleveland Heights community has expressed strong negative feedback about the placement of the sharrows relative to the curb. This has been a contentious topic. The Manual of Uniform Traffic Control Devices (MUTCD) recommends for municipalities to install sharrows at four feet. However, because of Ohio State Law, the city of Cleveland Heights decided instead to install sharrows at two and half feet from the curb. To learn more, and to give your feedback to the city, please fill out this petition/survey. The results will be presented to the city to help plan future sharrow placement.