Studies show that bike stopping laws do not raise safety concerns among cyclists or drivers

Laws that allow cyclists to treat stop signs as yield signs do not lead to unsafe behavior among cyclists or drivers, according to a groundbreaking study from Oregon State University.

The project by OSU College of Engineering researchers featured a novel experimental technique — linking separate bicycle and motor vehicle simulators — and the results are important as more states consider implementing bicycle stop zone laws, says David Hurwitz, the study’s leader.

The study was published in the journal Transport Research Part C: New Technologies.

“This required completely connecting two independent simulators, letting the test subjects run in pairs at the same time and letting each test subject interact with the other’s avatar in a shared virtual world,” says Hurwitz, professor of traffic engineering.

“We evaluated safety-related behaviors related to the Idaho Stop laws, which went into effect in 1982 but were largely ignored across the country until recently.”

Since 2017, seven states have followed Idaho’s example and passed laws against bike stops, including Oregon in 2019 and Washington in 2020. The others are Arkansas, Delaware, North Dakota, Oklahoma and Utah, and several more states have considered introducing laws.

The laws vary in their specifics, but the basic idea is that cyclists are allowed to treat static stop signs as yield signs. The main reason supporters like the laws is that they allow cyclists to maintain their speed, which theoretically reduces intersection congestion and the risk of accidents because cyclists can get through the intersection faster.

Nearly half of all crashes between bikes and cars occur at intersections, Hurwitz said. In 2022, the latest year for which figures are available, 1,105 bicyclists in the United States were killed in collisions with motor vehicles, according to the National Highway Traffic Safety Administration – a 13% increase from the 976 fatalities in 2021.

“The focus of previous research has been on analyzing crash data and why drivers are motivated to perform a rolling stop even when it is illegal in their state,” he said.

“Nobody has studied how well laws against stopping bicycles work or what happens when you educate people about them. Our connected simulator study design allows us to evaluate the behavior of drivers and cyclists and their understanding of the law.”

The study, which also included OSU graduate Rhonda Young of Gonzaga University and Kevin Chang of the University of Idaho, observed 60 people in pairs as they played out 16 “live interaction” scenarios in which a cyclist and a motorist encountered each other at an intersection with stop signs.

Previous studies have shown that drivers tend to react more aggressively toward cyclists when they believe they are breaking the law, Hurwitz said.

In this study, time-space plots showed that bicyclists yielded rather than stopped after being informed about the roll-stop law and passed through intersections faster. In contrast, car drivers approached intersections either more slowly or at a similar speed after being informed about the law.

“The results suggest that more education on rolling stop laws would be beneficial. This research will provide information to decision makers to support future legislative action, create educational programs and design robust enforcement practices,” Hurwitz said.

That’s especially important in places like the Pacific Northwest, he added, noting that Oregon and Washington have two of the largest percentages of bike commuters in the country. About 2 percent of workers in Oregon bike to work, and just under 1 percent of workers in Washington.

The League of American Bicyclists’ 2017 American Community Survey report shows that Portland has the second-largest number of bike commuters in the United States, second only to New York City. Portland has about 22,000 bike commuters and Seattle has about 17,000.