If you don't buckle up, you are putting more than yourself at risk: Passengers in the rear who don't wear a seat belt also pose a serious threat to those up front. Epidemiologist Masao Ichikawa of the University of Tokyo reached this conclusion after studying 100,000 vehicle crashes logged by Japan's traffic registry. His analysis shows that almost 80 percent of front-seat deaths could have been avoided if riders in the back had also belted up.
In head-on collisions, Ichikawa found, belted front-seat riders were more than six times as likely to be killed if there were unbuckled riders in the back. The fatality rate in these cases was similar to that for front-seat passengers who were not wearing a seat belt at all. "It's not that surprising. If a car that is traveling 50 kilometers [30 miles] per hour is stopped dead, 150 pounds in the backseat are going to be thrown into the front with an impact strong enough to be deadly. There's no reason seat belt laws shouldn't include the backseat," Ichikawa says. Only 14 states extend their seat belt laws to passengers in the rear.