UC Irvine

Bicycle infrastructure preferences vary by user experience and comfort, but evidence suggests both cyclists and drivers perceive separated bike lanes as safer than shared lane markings (sharrows). Little is known about sharrows impact in real-world settings, as no observational studies have evaluated their before and after installation impact. Santa Ana, California, incorporated sharrows into its active transportation plan to increase and encourage safe riding in a downtown commercial corridor where separated bike lanes were not feasible. Researchers conducted a natural experiment using a pre-post study design, collecting baseline data in 2015 before installation, and follow-up data in 2016 and 2017. A total of 54 hours of direct bicycle observation was conducted across two target areas over three years (2015 – 2017). A modest increase in bicycling was observed from 2015 to 2016, but was not sustained into 2017. Sidewalk and wrong-way riding increased slightly over time, while participation by female riders and older adults (65+) declined post-intervention. Sharrows offer a low-cost, scalable approach for promoting road sharing and guiding cyclists toward safer positioning, particularly in resource-constrained urban areas. This study’s real-world evaluation underscores the importance of tailoring active transportation infrastructure to meet safety and accessibility needs for all. Findings suggest sharrows are effective when paired with complementary strategies, such as targeted education, driver awareness efforts, or enhanced infrastructure, to better serve diverse populations and promote long-term engagement in bicycling. Further research can build on these insights by integrating user-centered evaluation methods and emerging data technologies.