SMART INVESTORS: Nils Bohlin: Three-point safety belt

Bohlin aimed to find an alternative design that would not only protect both the upper and lower body, but would also be comfortable and simple to use. He spent about a year devising a system that had one strap that would go across the chest and one that would go across the hips, with a joint for these two straps located just next to the driver’s hip. The design held both the upper and lower body in place, and was simple enough that the driver could buckle up with one hand.

Nils Ivar Bohlin (July 17, 1920 – September 26, 2002) was a Swedish inventor who invented the three-point safety belt while working at Volvo. Born in Sweden, he received a diploma in mechanical engineering from Härnösand Läroverk in 1939. In 1942 he started working for the aircraft maker Saab as an aircraft designer and helped develop ejection seats. In 1958 he joined Volvo as a safety engineer. He is credited with the invention of the modern 3-point safety belt, now a standard safety feature in all cars. He retired in 1985.

Bohlin helped to design and manage multi-disciplinary accident investigation teams for cars and trucks. Safety belts were in use at the time, but the most prevalent design used a single strap with a buckle over the stomach. This design risked injury to body organs in high-speed crashes.

Bohlin aimed to find an alternative design that would not only protect both the upper and lower body, but would also be comfortable and simple to use. He spent about a year devising a system that had one strap that would go across the chest and one that would go across the hips, with a joint for these two straps located just next to the driver’s hip. The design held both the upper and lower body in place, and was simple enough that the driver could buckle up with one hand.

In 1959, Volvo became the first auto maker to introduce Bohlin’s three-point safety belt design. At first the company put the belts in cars designated only for its home market, but by 1963 all Volvos came equipped with front seat belts, and the company decided to make the design free for use by all car makers.

In 1967, Bohlin presented a paper, “A Statistical Analysis of 28,000 Accidents with Emphasis on Occupant Restraint Value,” on behalf of Volvo, at the 11th Stapp Car Crash Conference. The report claimed that the belt had already saved thousands of lives, reducing the risk of injury or death in car accidents by as much as 75 per cent. This report helped inspire the United States’ National Highway Safety Bureau to implement a law requiring automakers to equip the front seats in passenger cars with three-point lap/shoulder belts. It persuaded a number of other national governments to do the same.

changed very little in its overall design. Improvements to the design have included the inertial reel, tensioners to eliminate slack, force limiters to control the forces needed to restrain the user, and better buckles. As of today, the U.S. National Highway Traffic Safety Administration estimates the belts reduce the risk of deaths in car crashes by at least 45 percent.

In 1969 Bohlin was assigned to the Central Research and Development Department at Volvo. Later he was named chief research engineer in the Advanced Engineering Department. He consistently managed matters related to general automotive safety, including initiating and managing Volvo’s Traffic Accident Research Group. Bohlin retired from Volvo in 1985. He earned several patents during his lifetime related to both aviation and automotive design and was recognized with numerous awards and honors.

In 1974 Bohlin was awarded The Ralph H. Isbrandt Automotive Safety Engineering Award. He was honored in 1979 and in 1985 by the National Highway Traffic Safety Administration in Washington, D.C. In 1995, he received a medal from the Royal Swedish Academy of Engineering Sciences. In 2002, he was inducted into the (U.S.) National Inventors Hall of Fame. On the day he was to be honored for this achievement, Bohlin died at age 82.