One day in 1952, John W. Hetrick was driving, with his wife and daughter in the front seat, when he had to swerve and brake quickly to avoid an obstacle. Instinctively, he and his wife put their arms out to shield their daughter in case of a crash. This inspired him to provide automobiles with air bags to protect people during accidents.
Hetrick had been an engineer in the U.S. Navy during World War II, and he recalled a compressed-air torpedo accidentally turning itself on, causing its canvas cover to shoot "up into the air, quicker than you could blink an eye." In 1952 Hetrick proposed using compressed air to inflate air bags rapidly during car crashes. He received a patent for his invention in 1953, but car manufacturers in the 1950s were more concerned with style than safety. Air bag technology improved and consumers became more safety conscious—the first air bags were offered as optional, but by the 1990s they had become standard.
An air bag system has three main components: the bag itself, a sensor for measuring the severity of a crash, and gas to inflate the bag in a severe crash. Air bags cushion sudden forward movement by spreading the impact over a greater area and slowing the impact so that it occurs over a longer time. Both decrease the damage done to bodies in a crash.
Although air bags have saved thousands of lives, they are not always sufficient to prevent death and injury during crashes. Travelers must also wear lap and shoulder seat belts, and automobiles must have padded dashboards and steering columns that can absorb energy during the impact of car crashes.
