AFTER SURVEYING Portland bike commuters for a year, Oregon Health and Science University doctors this month published one of the first long-term studies looking into urban biking injuries.

The shocking results? Twenty-two percent of commuters suffered at least a minor injury on their bike, with five percent suffering injuries serious enough to land them in the hospital. Also surprising: Of the 962 commuters studied, the rate of injury was the same for advanced and beginning bikers. Dr. John Mayberry, an author of the study and a trauma surgeon in Portland for 15 years, talks about what the research means.

MERCURY: Your study shows that 22 percent of cyclists experienced a "traumatic or serious injury." What qualifies as traumatic?

DR. JOHN MAYBERRY: You had to actually be injured. It could just be skinning your knee or spraining your ankle, but it couldn't just be a near miss. I think it was surprising. We were expecting fewer injuries.

What can this study tell us about making biking safer?

We can only surmise this—we can't prove it— but one of our major conclusions is that it's not the riders themselves who are dangerous. It's the environment. Maybe 10 years ago, if we'd done this study, we'd have found different results. But it could be that Portland's education infrastructure and cultural infrastructure is such that the most bang for your buck in injury prevention is building new facilities. What we did find is that poor roadway surfaces were a factor in 20 percent of serious events. Here's a very simple way to improve safety. It's not just enough to have the infrastructure—you need to maintain it.

Will this dissuade people from biking in Portland? Looking at the numbers, it seems pretty dangerous.

It's possible it will. The 22 percent might dissuade people. But I think it's also important to know that there is a risk. I also think it might encourage people. People might say, "It's risky for me, I'm a beginner," but what this shows is that Portland's infrastructure is good enough that there's no difference in the likelihood of being injured even if you're a beginner. You can get up and go.

Read the full study here.