Seat belts were once simple straps that mainly served to avoid being tossed from automobiles on bumpy roads. Even then, most drivers and passengers didn’t bother with them.

“The early belts were … pretty much ignored,” says Erin Breen, the director of the Road Equity Alliance Project at the University of Nevada, Las Vegas.

But as more and more Americans bought and drove cars, traffic accidents became more common, and leaders in the medical community began calling for improving car safety.

Neurologist Dr. C. Hunter Sheldon pointed out in the November 5, 1955 issue of Journal of the American Medical Association that approximately 10 percent of all autos on the road the previous year had been involved in an accident. “If injured, you have one chance in 15 of receiving an injury severe enough to result in permanent total disability,” he wrote. Retractable seat belts, Sheldon argued, could save lives—if people wore them.

The design that ultimately became the prototype for seat belts still used in automobiles today, arrived by the end of that decade, in 1959.

The earliest seat belts weren’t actually made for cars, but for aircraft. In the 19th century, English engineer George Cayley created a seat belt to use on his monoplane glider, an early aircraft flown in the late-19th century. The simple lap belt secured passengers to their seats during turbulent flights and rough landings and takeoffs.

In 1885, Edward J. Claghorn of New York was awarded the first patent for his own version of the “Safety Belt,” which looked like a modern-day climbing harness.

“The belt, which may be made of leather-and webbing…and of sufficient length to pass around the waist of the person using it, is provided at one of its ends with a buckle, for the other end to engage with when securing the belt to the person.,” the patent application reads.

During World War I and World War II, military pilots wore standardized restraint systems. However, outside of military and aviation communities, everyday people were not exposed to seat belts until automobiles became widely available.

When Henry Ford developed mass production and standardization techniques for automobile part manufacturing, cars became more affordable and available to Americans.

The Nash Motors Company, an automobile manufacturing company based in Wisconsin, became the first company to offer seat belts in their cars in 1949. However, the standardized belts were not widely adopted.

“The history of the seat belt is interesting for the resistance it has encountered since it was first introduced by the Nash Company in 1948. Those early belts were not popular, and neither was any design, for decades,” says Breen.

By the mid-1950s, as car accidents began to rise, medical leaders like Shelden pointed out that for seat belts to save lives, people had to wear them. “There is no doubt that seat belts in passenger cars will prevent many injuries and fatalities, if only the public will fasten them,” he wrote in his 1955 article. “At least one can be sure that until improved designs are available the public is not going to take full advantage of this means of safety.”

Sheldon's research led him to propose the the idea of airbags, door locks, roll bars—and retractable seat belts—to improve passenger safety.

By 1955, new innovations were already underway. That year inventors Roger Griswold and Hugh de Haven applied for a patent for a combination shoulder and lap safety belt. While the belt restrained the passenger’s shoulders, torso, and hips like modern seat belts, the belt buckle was fastened in the middle.

In 1958, Glen Sheren applied for a patent for the “Sheren Safety Belt." This belt featured two straps with one attached to the vehicle floor and the other attached to the car door. The belt was designed to keep the car doors closed during a collision, which would maintain the vehicle’s structural integrity and purportedly decrease chances of catastrophic injury.

The most significant advance was the introduction of the three-point seat belt in 1959. Nils Bohlin was working for Volvo as the company’s first chief safety engineer, when he developed the three-point lap and shoulder seat belt.

Bohlin had a background in aviation and had previously designed ejector seats for Saab fighter airplanes in the 1950s, which used 4-point restraint harnesses. Bohlin’s seat belt was easy for drivers to use and secured both the upper and lower body. It buckled below the hip into a stationary anchor point.

While there have been modifications to some elements of the modern seat belt since Bohlin’s original invention, the basic design remains the same. Its structure secures people to their seats by strapping them in at the strongest areas of the body: the shoulders, hips and sternum.

“Today's seat belts are instrumental in saving lives and protecting the occupants of vehicles,” says Thomas Zeller, a professor of history at the University of Maryland.

After Bohlin’s invention, all Volvo vehicles were equipped with the three-point seat belt and the Volvo Corporation made the design available for free to other car manufacturers. From 1968 onwards, the three-point seat belt was required on all newly manufactured American vehicles.

In 1966, Congress passed the National Traffic and Motor Safety Act to set new safety standards for motor vehicle and road safety. In 1984, New York became the first state to pass a mandatory seat belt law. The law, known as a primary enforcement law, gave authorities the right to pull someone over and fine them for not wearing a seat belt.

Some complained that seat belts impinged on their rights. “[It’s an] ugly reality that a mandatory-seat-belt law violates the right to bodily privacy and self-control of every front-seat occupant in every motor vehicle driving on the roads of New York State,” a Connecticut reader wrote in a New York Times Letter to the Editor on February 5, 1986.

Despite protests, it was clear that seat belts were effective in preventing fatalities and injuries resulting from car accidents and, by 1994, all states had some form of seat belt legislation (only New Hampshire currently does not require adults to wear seat belts in the front seat). In 2023, the National Highway Traffic Safety Administration estimated that 91.9 percent of Americans wear seat belts while in the front seat of vehicles.

“There are so many stories of how seat belts have saved thousands of lives,” Breen says. “But the reality is that only because most states mandate them are they widely used.”