Last September a plucky psychologist at the University of Bath in England announced the results of a study in which he played both researcher and guinea pig

His findings, published in the March 2007 issue of Accident Analysis & Prevention, state that when Walker wore a helmet drivers typically drove an average of 3.35 inches closer to his bike than when his noggin wasn't covered. But, if he wore a wig of long, brown locks—appearing to be a woman from behind—he was granted 2.2 inches more room to ride.

"The implication," Walker says, "is that any protection helmets give is canceled out by other mechanisms, such as riders possibly taking more risks and/or changes in how other road users behave towards cyclists.