The Missouri State legislature has passed a bill relaxing that state’s motorcycle helmet law by requiring helmet use only on interstate highways and at all times for riders under the age of 21.

If Governor Jay Nixon signs it, Missouri will become the latest state to join a trend of repealing or eliminating mandatory helmet laws. In 1975, 47 states required helmets for all motorcyclists. Now, just 20 do.

There has been a direct correlation between increasing motorcycle fatalities and a decline in the number of states requiring helmet use. Furthermore, head injuries have been the leading cause of those deaths.

The statistics are eye opening. According to the National Highway Traffic Safety Administration (NHTSA), more than 5,000 motorcycle riders were killed in crashes in 2007, the highest number since NHTSA began tracking fatality crash data in 1975. Motorcycle deaths now account for 13 percent of all traffic deaths, even as automotive fatalities have fallen to the lowest levels on record per million miles traveled. Motorcycle injuries were also up by 17 percent in 2007.

Increased numbers of motorcycle riders have contributed to some of these grim statistics, but the correlation between relaxed helmet use and increased fatality rates is notable.

Florida eased its helmet law on July 1, 2000. Within two years, motorcycle fatalities climbed by 81 percent and hospital admissions for motorcycle riders with head injuries increased by 82 percent.

Consumer Reports has long supported helmet use for all motorcycle and motor scooter riders, along with proper training. Motorcycling can be a fun and economical alternative to an automobile for some drivers, as long as you understand and accept the increased risk. If you choose to ride, minimize your risk by wearing full protective gear including a D.O.T. approved full-face helmet, and take a safety course like those offered through the Motorcycle Industry Council.

—Jim Travers