In December 2012, Dr. Fred Rivara gave an alarming TED Talk about the spread of bikeshare programs across the nation. This was a big problem, he argued, because bikeshare riders generally do not wear helmets. He predicted mass carnage as a result, and published a paper that purported to show a 14% increased risk of head injuries as a result of bikeshare.
But when the data in the paper was examined, it was clear that bikeshare had the opposite effect. Cities with bikeshare programs saw a substantial reduction in head injuries.
It is not the first time Dr. Rivara has cried wolf.
Beginning in 1989, he published a series of papers claiming that bike helmets reduce the risk of head injury by a whopping 85%. He is the original bike helmet alarmist. And while his papers were heavily criticized for their methods and conclusions, that did not prevent legislators from passing mandatory helmet laws.
But following passage of the helmet laws, a funny thing happened: There was no change in the rate of bicyclist injuries or fatalities. For example, a study of Canadian helmet legislation in the BMJ states: “we were unable to detect an independent effect of legislation on the rate of hospital admissions for cycling related head injuries.” A study of Australia helmet legislation (“No clear evidence from countries that have enforced the wearing of helmets”) made the same conclusion. Australia, by the way, is the most perfect laboratory for bike helmet effectiveness, because the entire country overnight instituted strict helmet laws. The fact that no effect was detected is astonishing, given Rivara’s claim that helmets are 65% effective against motor vehicle collisions.
When real world experimental data fails to validate a theoretical model, it means the model is wrong. Twice now, Dr. Rivara’s theory has failed in dramatic fashion. The fact that he refuses to give up his theory means he is nothing more than a crackpot.