Seat belts

How it saves lives

In a crash the danger is not the sudden stop of the car but the second collision, when an unbelted body keeps moving and hits the dashboard, the windshield, or another person. A three-point belt catches that motion across the strong bones of the chest and pelvis and keeps you inside the vehicle, where you are far more likely to survive. NHTSA estimates the belt cuts the risk of a fatal injury by about 45 percent for people in the front seat of a car, and by 60 percent in a light truck.

The story

Before 1959 most cars had, at best, a simple lap belt that could do real damage in a hard crash. Nils Bohlin, an engineer Volvo hired away from making ejector seats for fighter planes, worked out that a single belt anchored at three points would hold both the chest and the hips. Volvo could have kept the design to itself. Instead it opened the patent so any carmaker could fit the belt, judging that lives mattered more than the licensing fee. The arithmetic since has been staggering. NHTSA counts an estimated 14,955 lives saved in a single year, 2017, and 374,276 over the four decades from 1975. The honest catch is that the belt only works when it is worn, and thousands still die each year unbuckled.