Seatbelts were experimental when they came out.
Some states still resisted.
Once the idea of safety benefits of seat belts caught on in the U.S. public, sales of seat belts skyrocketed. Auto companies offered seat belts as optional equipment and were even sold at local gas stations.
Since 1966, American vehicles are required to have seat belts in their cars. As such, by 1975, most first-world countries had a seat belt requirement in their cars. Once they became more common in cars, laws soon followed afterwards. By 1970, the world’s first seat belt law was created in Victoria, Australia, which required passengers to wear their seat belts at all times. In the U.S., seat belt laws came around the time of the creation of The National Traffic and Motor Vehicle Safety Act of 1966.
Though they were required by law to be in cars, wearing seat belt laws were a different story. The National Ad Council ran countless ads for 25 plus years encouraging drivers to “Buckle Up.” States slowly starting implementing laws and by 1995, every state except New Hampshire had “Click it or ticket” laws. Currently, all states have a seat belt enforcing law.
Air bags can hurt you, they put them in every new car now.