Research on the effects of motorcycle helmet laws on fatalities shows that more than 22,000 motorcyclists who died on the road over the past five decades would have survived if more states required helmets for all riders.

The Insurance Institute for Highway Safety study examined annual motorcyclist deaths in states with and without helmet laws for all riders and whether or not the riders wore a helmet at the time of death, thereby estimating helmet use rates in the states when such laws were in effect and when they weren’t. Using prior research that found helmet use cuts fatality risk by 37%, it estimated the cumulative results of helmetless riding per state.

The nonprofit group used 1976 as the starting point of the research period because that was the year federal highway safety and construction funding ceased to be tied to all-rider helmet laws. Before, nearly every state had such laws, but after the funding restriction was lifted, most relaxed theirs or ended them completely, IIHS said. Now just 17 states and Washington, D.C., have all-rider helmet laws.

Despite the laxer regulation, overall U.S. helmet use has increased, though it was generally two to three times higher in states with all-rider laws over the research period, IIHS says.

“We understand that requiring helmets for all riders everywhere would be unpopular with some motorcyclists, but this could save hundreds of lives each year,” said IIHS Director of Statistical Services Eric Teoh, who conducted the research. “Those aren’t just numbers. They’re friends, parents and children.”

California, which has had an all-rider helmet law since 1992, nevertheless had the highest total of motorcyclist fatalities during the period at 2,536, a distinction that IIHS says results from its large population and long riding season. It listed Texas, Florida, Illinois, Ohio, Indiana and South Carolina as having the next highest fatality totals, noting that those states allow helmetless riders.

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