tip of the hat to Nils Bohlin, he may have saved more lives globally than anyone who hasn't cured a disease. He invented the first three-point seatbelt, which was 1st sold in a Volvo PV544 in 1959.

Nils Bohlin, a former aviation engineer who helped develop ejection seats for aircraft before joining Volvo in the '50s

Bohlin believed that, while Y-shaped belts marked a step in the right direction in terms of adequately distributing crash forces over a wider area, it was equally important to ensure those forces were distributed across strong areas of the body. So, instead of running belts willy-nilly across occupants' bodies, Bohlin designed a belt pathway that crisscrosses the most robust pieces: the shoulder, chest, and pelvic bone.

Ease of use was a key consideration, and Bohlin settled on a simple V shape, which enabled users to reach over, grab the buckle, and pull it (and with it, the shoulder and lap portions of the belt) across their body to the latch at the base of the seat.

The newfangled belt Bohlin and Volvo developed failed to catch on immediately. Even Volvo only installed the three-pointers in the front seats at first; it would take until 1967 for the automaker to add them to its cars' rear seats.

Volvo even tracked down every crash involving its vehicles over one year in Sweden (28,000 crashes in all) and found data supporting unequivocally that three-point belts helped spare drivers and passengers death and reduced injuries by 50 to 60 percent.

Despite the advancements with inertia reels, pretensioners, load limiters, the three-point belt's basic design hasn't changed since Bohlin created it.

https://www.caranddriver.com/news/a28775593/three-point-seatbelt-history