Jan. 4, 2002 -- Most people know that wearing a seat belt can save their life, but now a new study shows that buckling up can also save the lives of the other people in the car.
Drivers and front-seat passengers are at a five times greater risk of dying in a car accident if the rear passengers are not wearing seat belts, according to a study conducted at the University of Tokyo.
The study, published in this week's issue of The Lancet, examined more than 100,000 front-seat occupants involved in car-to-car crashes between 1995 and 1999 in Japan. In all cases there were at least two passengers in the rear seat.
The most dramatic effect was seen in head-on collisions. In these types of accidents, the lack of rear seat-belt use increased the risk of dying for the driver by 600 percent: For the front passenger, death risk increased more than 700 percent.
Passengers Catapulted Forward
According to the study, a great deal of injury to those in the front is caused by the force of the rear passenger being thrown forward. Based on the weight of an average adult, an unrestrained rear passenger is thrown forward with the force of more than 3 ½ tons in a 30 mph crash.
"They catapult into the front part of the vehicle and strike the upper body of the front-seat occupant in the back of the head and neck," said Dr. Fred Hansen, an emergency room physician at the University of Iowa.
The study's authors estimate the total number of deaths could have been reduced by almost 80 percent if rear passengers had been wearing seat belts.
It is speculated that the risk of death in side and rear crashes was much lower because rear passengers are not thrown directly into the front passengers upon impact.
Currently, only 13 states and the District of Columbia require rear seat passengers to wear seat belts.
A telephone survey conducted by the Insurance Institute for Highway Safety in 1998 found that only 38 percent of Americans always use seat belts when riding in the rear.
The authors conclude that, "All car occupants should wear seat belts for protection of not only themselves but also the other passengers."