You may have read yesterday’s USA Today article on the National Transportation Safety Board’s (NTSB) call for mandatory helmet laws for all motorcycle riders in the United States.

Motorcycle rights groups oppose the move by the NTSB, criticizing it for interfering in state affairs and proposing laws that are not needed, while highway safety groups are in favor.

According to the NTSB, motorcycles comprise just 3 percent of vehicles on the nation’s road but are involved in 13 percent of fatalities. Head injury is a leading cause of death in motorcycle crashes, says the U.S. Department of Transportation.

A map accompanying the USA Today article shows those states that require helmets for all riders, states that require helmets for some riders and states that have no helmet laws.

This got us thinking about motorcycle helmet laws around the world.

According to the World Health Organization (WHO), motorcyclists wearing a good-quality helmet can reduce the risk of death in a road crash by almost 40 percent and the risk of severe injury by over 70 percent.

Yet, only 40 percent of countries have motorcycle helmet laws that cover both riders and passengers, and mandate quality standards for helmets.

A map shows helmet laws and standards by country.

The WHO also has information on road safety laws by country relating to other key risk factors, such as speed, drink-driving, seat belts and child restraints.

Check out the I.I.I. issues update on motorcycle crashes.