Bike boxes protect bicyclists, PSU study concludes

Bicyclists heading out for the road this coming winter will be getting more visibility on the street. The Portland Bureau of Transportation announced that it will add 11 more bike boxes in key areas deemed as high-risk for riders.

The decision was influenced by a yearlong study completed by Portland State researchers from the Initiative for Bicycle and Pedestrian Innovation. The study found that the 12 bike boxes installed by PBOT in 2008 are effective, at the very least, in influencing behavior that can improve bicyclists’ safety.

Following the study’s release, PBOT is convinced that the 14-foot-long green boxes extending from bike lanes that put cyclists in front of cars at traffic stops are effective. Researchers are currently identifying

intersections where the new boxes will go. Each box will cost about $6,000 due to the thermoplastic material used.

There are 12 bike boxes in the Portland area, nine of which are painted green. All of them are located in areas that are considered high-risk for cyclists because of right-turning cars.

Researcher Jennifer Dill, a professor from the School of Urban Studies and Planning, said they are looking to answer three questions in their study: whether people understand and use bike boxes correctly, whether the boxes improve safety and whether the color green makes a difference.

“Our conclusion is that, ‘yes,’ most people understand them; most motorists stop completely behind the box,” Dill said. According to the study, 77 percent of observed motorists stopped behind the green box, and 73 percent of cyclists correctly stopped ahead of motor vehicles. Dill added that although some bicyclists chose to stay in the bike lane at the traffic stop, they were still in front of motor vehicles where they could be seen.

Dill and her colleague Dr. Christopher Monsere, an assistant professor from the College of Engineering and Computer Science, analyzed 83 of 918 hours of video recordings of 5,315 cyclists. Their team also viewed 139 hours of conflict between cyclists and motorists and 14 hours of motorist yielding behavior.

According to Dill, when it comes to safety, there are several indicators that bike boxes could improve safety and decrease the number of conflicts between drivers and cyclists.

In the study, the number of observed conflicts decreased from 29 percent before the installation of bike boxes to 20 percent after. The researchers believe that positive yielding behavior has increased with the addition of the bike boxes.

The researchers were also interested in people’s perception of safety on the road. In their surveys, 42 percent of motorists felt that driving through the intersections was safer with the bike boxes, compared with 77 percent of bicyclists. In addition, Dill and her team found that the majority of people surveyed prefer the color green, although there are no marked differences in terms of safety between colored boxes and non-colored ones.  

According to PBOT, bike boxes have been used in several other countries, such as Canada, France and the U.K. After Portland’s adoption of bike boxes, cities such as Austin and San Francisco have followed suit.

“I get e-mails every week from other cities that are considering bike boxes, and they want to know what we did in our study,” Dill said. “A while ago, I presented [the bike box study] at a conference in Israel so they too got interested in it.”  

Southwest Broadway Avenue, which runs through PSU’s campus, was chosen as one of the 12 testing sites when PBOT first installed bike boxes in 2008. They received mixed reception from student bicyclists; a majority of those interviewed said the bike boxes increased visibility but that more information needs to be available on how to properly use them.

“I think that [the bike box] definitely helped make the car drivers realize that they’re not the only ones on the road,” said Joseph Lockerby, a second-year sociology student. “Sometimes, though, I’ve seen cars stop on the bike box even though there’s a huge sign that tells you where to stop.” Lockerby said pedestrians sometimes walk in the bike lane thinking that it is part of the sidewalk, which is a minor nuisance to cyclists.

According to PSU Transportation and Parking Services, the school currently does not have any pamphlets or posters to educate bicyclists and motorists about the use of bike boxes.

“The good thing is that Broadway is pretty busy so cars drive slow here,” said Stephanie Mitchell, a student bike commuter. “I’m a bit hesitant though, to move from the bike lane to the [bike box] if there’s a big SUV behind me.”

Dill said she is happy to know that her team’s work is being applied to solve a problem in the community.

“I want to do research that is useful to practitioners and policy makers and hopefully has a positive effect on people’s life and our environment,” Dill said. “Most of the research that I’ve done always had that intention.”