You've probably seen the white outline of a bicycle painted on the road with two arrows. That symbol is called a sharrow. It means that drivers and bicyclists are expected to share the lane. Since sharrows were first implemented in Denver two decades ago, they've spread throughout the United States and even abroad.
Sharrows are distinguished from formal bike lanes, which are a separate lane for bicycles, and endorsed as a way cities can keep cyclists safe. But University of Colorado Denver associate professor of engineering Wesley Marshall, along with doctoral candidate Nicholas Ferenchak, studied sharrows in Chicago. They suggest that sharrows aren't as effective for bicycle safety as bicycle lanes. The two plan to submit their research to the journal Accident Analysis and Prevention.
Ferenchak spoke with Colorado Matters host Nathan Heffel.