Motorcycles are more difficult for motor vehicle drivers to spot than cars because of their smaller profiles. In addition, drivers are conditioned to look for other cars, not motorcyclists.

This conditioning is due in part to the relatively small number of motorcycles on the roads compared to other motor vehicles.

According to statistics from the National Highway Traffic Safety Administration (NHTSA), although there are over 6.2 million motorcycles registered in the United States, they represent only about 3 percent of all registered vehicles. Yet motorcycles are far more dangerous in an accident representing approximately 11 percent of all highway fatalities each year. Approximately 80 percent of reported motorcycle crashes result in injury or death; a comparable figure for automobiles is about 20 percent.

Further statistics show that in approximately 77 percent of fatal motorcycle accidents, the motorcycle was struck in front, with only 7 percent struck in the rear. Significantly, in 41 percent of the fatalities, the motorcycle was going straight and the other vehicle was turning left. Other motorcycle accident causes include the motorcyclist riding in the blind spot of a motor vehicle, sudden evasive movement as a result of road conditions such as potholes, wet leaves or other obstructions, and obstructed sight from large vehicles such as sport utility vehicles or trucks that may block motorcyclists entirely.

These causes can be countered with more attentive driving by both automobile drivers and motorcyclists, and form the basis for the motorcycle motto Check Twice, Save a Life. Studies have consistently found that motorcycle helmet use saves lives and reduces the probability and severity of traumatic brain injuries, the cost of medical treatment, the length of hospital stay, the necessity for special medical treatments, and the probability of long-term disability. Helmet use increases significantly with mandatory helmet use laws.

In Massachusetts, the law requires that every person operating a motorcycle or riding as a passenger shall wear a protective head gear, and requires eye glasses, goggles or a protective face shield if there is no windshield. As a result, Massachusetts has 97 percent helmet use, compared to about 61 percent nationally where 26 states require helmets for those under 18 or 21 only, and 3 states (New Hampshire, Iowa and Illinois) have no mandatory helmet law.