Laws that allow cyclists to yield at a stop sign, rather than come to a complete stop, don’t increase the likelihood of unsafe driving or cycling behaviors, researchers at Oregon State University have found.

However, Oregon drivers and cyclists could benefit from more education on the rolling-stop laws, studies say.

In 2019, Oregon became one of a handful of states to legalize the so-called “Idaho stop,” which allows cyclists to treat flashing red lights and stop signs as a yield, rather than requiring cyclists to adhere to the same full stop laws as vehicle drivers. Bike riders still have to stop at a solid red light.

Oregon State researchers wanted to know what this meant for safety.

“What we would hate to see is an increased frequency and severity of crashes, especially with bicyclists or pedestrians,” said David S. Hurwitz, director of the Kiewit Center for Infrastructure and Transportation Research at Oregon State.

The Oregon researchers teamed up with academics in Idaho and Washington to interview transportation officials, law enforcement officers and bicycle advocates in states that have implemented rolling stops, to survey members of the public and to conduct a lab study about driving and cycling behavior.

Researchers wanted to know: Did Oregon “make an OK choice” in allowing rolling stops statewide? The answer was yes, Hurwitz said.

“Folks should feel reasonably confident that the implementation of these laws aren’t going to generate significant decreases in safety,” he said.

Surveys found a “need for increased awareness” about rolling stop laws. Residents of Idaho, the first state to implement the yield law in 1982 were more familiar with the rule than people in Oregon and Washington, which only implemented those new laws circa 2020.

In fact, nearly 60% of the 80 Corvallis-area drivers and cyclists that Oregon State researchers recruited for a lab study on their driving habits were unaware of the state yield laws before participating in the study, researchers found.

The lab study tracked the riding and driving behaviors of nearly 40 cyclists and 40 drivers before and after an education seminar on the yield law. Participants drove or cycled two routes on a real-world simulator, then received training on Oregon’s law, then drove two more routes. They knew at the time that researchers were monitoring their behavior.

Both drivers and bicycle riders changed their behavior when they learned about the law, the study found.

Some drivers who knew about the yield law slowed down earlier when they approached a stop, then drove more slowly through intersections, the study found. Nearly 70% of the lab participants who drove said they worried about cyclist safety at intersections after learning about the law, researchers found.

Cyclists, who before typically stopped at stop signs, were more likely to yield at a stop sign then cycle through an intersection at higher speeds once they had learned about the law, the study found. Cyclists were still more likely than not to come to a complete stop when there was a car at an intersection, the paper said.

Cyclists’ increased speeds suggest that they were “more comfortable and efficient” navigating through intersections without stopping when they learned about the law, the study says. That could cut down on travel time and improve traffic flow, the study said. But it “also raises concerns about the compliance of yielding behavior, which could lead to higher crash risks if bicyclists do not yield appropriately,” the study said.

In general, researchers found that bicyclists “did not contribute to dangerous behaviors” when rolling stops were allowed, the study says. Cyclists who knew about the rolling-stop law did not try to zoom through tight gaps in front of high-speed cars, Hurwitz said. Drivers also did not ignore the cyclists or accelerate toward them, he said, and actually demonstrated increased visual attention to bike riders.

In every measure researchers observed, driving and cycling behaviors either remained the same, or improved, when people knew about the law, Hurwitz said.

“We look at that as quite a positive outcome,” he said.