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…