Nils Bohlin, the Swedish engineer and inventor responsible for the three-point lap and shoulder seatbelt–considered one of the most important innovations in automobile safety–is born on July 17, 1920 in Härnösand, Sweden.

Before 1959, only two-point lap belts were available in automobiles; for the most part, the only people who regularly buckled up were race car drivers. The two-point belts strapped across the body, with a buckle placed over the abdomen, and in high-speed crashes had been known to cause serious internal injuries. In 1958, Volvo Car Corporation hired Bohlin, who had designed ejector seats for Saab fighter airplanes in the 1950s, to be the company’s first chief safety engineer. (A relative of Volvo CEO Gunnar Engelau had died in a car crash, which helped motivate the company to increase its safety measures.) Bohlin had worked with the more elaborate four-point harnesses in airplanes, and knew that system would be untenable in an automobile. In designing the new seat belt, he concentrated on providing a more effective method of protecting driver and passenger against the impact of the swift deceleration that occurred when a car crashed.

Within a year, Bohlin had developed the three-point seat belt, introduced in Volvo cars in 1959. The new belts secured both the upper and lower body; its straps joined at hip level and buckled into what Bohlin called “an immovable anchorage point” below the hip, so that they could hold the body safely in the event of a crash. According to Bohlin (as quoted by The New York Times in his 2002 obituary): “It was just a matter of finding a solution that was simple, effective and could be put on conveniently with one hand.”

In the interests of safety, Volvo made the new seat belt design available to other car manufacturers for free; it was required on all new American vehicles from 1968 onward. Since 1959, engineers have worked to enhance the three-point belt, but the basic design remains Bohlin’s. At the time of Bohlin’s death in September 2002, Volvo estimated that the seat belt had saved more than one million lives in the four decades since it was introduced. In the United States alone, according to the National Highway Traffic Safety Administration, seat belts save more than 11,000 lives each year.