New report evaluates safety implications of stop-as-yield laws for bicyclists
In California, a bill to instate a "stop-as-yield" law for bicyclists — where cyclists can treat stop signs as yield signs — has been introduced multiple times but
has consistently failed to be put into law due to safety concerns. But do stop-and-yield laws cause more or fewer cyclist crashes?
A new report by UC Berkeley Safe Transportation Research and Education Center (SafeTREC) postdoctoral researcher Iman Mahdinia, director Julia Griswold, and SafeTREC alum Rafael Unda, Soheil Sohrabi, and Offer Grembek aims to address this issue and inform policymakers on the safety effects of adopting this legislation.
The report, "Evaluate the Safety Effects of Adopting a Stop-as-Yield Law for Cyclists in California," compares cyclist crash data from five states that have stop-as-yield laws in place—Idaho, Arkansas, Oregon, Washington and Delaware—to five states that do not, including California. By analyzing this data, the researchers could identify whether stop-as-yield laws have historically affected cyclist crash rates, and in turn evaluate the safety implications of implementing such a law in California.
"Using an observational before-after study with state-level comparison groups, the study examined changes in cyclist crash frequencies following the implementation of the stop-as-yield laws," the report states. "Additionally, we used a random-effects negative binomial regression model with panel data to estimate the overall impact of these laws."
The report finds that there are no significant changes in cyclist crash rates between states that have stop-as-yield laws and states that do not. As a result, a consensus was not able to be drawn as to whether a stop-as-yield law would positively or negatively affect cyclist or road safety in California.
Additionally, the researchers identify several areas for potential future research on stop-as-yield laws, such as "considering more control variables,such as economic, environmental, cultural, driving, and cycling behavioral factors of the studied communities," and investigating the effects of stop-as-yield laws in specific locations such as "stop sign–controlled intersections in urban, rural, and suburban areas."