The National Transportation Safety Board (NTSB) is calling for bicyclists across the U.S. to wear helmets in a bid to reduce the number of fatalities on the country’s roads.

In the NTSB’s first examination of bicyclist safety since 1972, the agency recommended all “50 states, the District of Columbia and Puerto Rico, require that all persons wear a helmet while riding a bicycle.”

It is one of the “critical changes” the report calls for to address the recent rise in fatal bicycle crashes involving motor vehicles, even as overall traffic deaths fell in 2018.

“If we do not act to mitigate head injury for more bicyclists, additional bicyclists will die,” said NTSB Chairman Robert L. Sumwalt.

The report states that less than half of bicyclists wear helmets and that head injuries are the leading cause of bicyclist fatalities. Investigators say the use of a helmet is the single most effective way for riders to reduce their chances of receiving a serious head injury.

According to NTSB investigators, the most frequent type of fatal collisions involving bicyclists occur while a motorist is overtaking a bicyclist in the stretches of roadway between intersections, prompting calls for separated bike lanes.

The report also recommends improving roadway design and increasing the visibility of bicyclists to reduce both fatal and serious crashes.

The report’s findings and safety recommendations are available at