It is not known whether any drivers turned around for a look after they passed the bicyclist. If they did, they would have been puzzled: "It was slightly embarrassing, because I had a beard at the time," Walker said. "I spent a couple of days going up and down the road wig on, and a couple of days going up and down the road, wig off."
Walker was trying to figure out whether his interventions changed the way drivers passed his bike. He came to two conclusions: Cars gave him more leeway when drivers thought he was a woman with curly black hair. And they gave him less leeway -- getting dangerously close -- when he wore a helmet.
Walker thinks drivers are influenced by unconscious stereotypes -- they may believe that female bicyclists are less steady, and that helmeted bikers are pros.
Again, it would be an error to draw the simplistic conclusion that bike helmets are a bad idea. Wearing a helmet does seem to change how you and other people on the road perceive risk -- but doing away with helmet laws could have unintended consequences, too.
"One big problem when you talk about risk is the extent to which people have an accurate idea of it -- I don't believe people have an accurate idea of the risks they are looking at," Walker said. "If they have just seen something happen to another person, people believe it is more likely to happen to them."
