A seatbelt (also known as a seat belt or safety belt) is a vehicle safety device designed to secure the driver or a passenger of a vehicle[1] against harmful movement that may result during a collision or a sudden stop. A seat belt reduces the likelihood of death or serious injury in a traffic collision by reducing the force of secondary impacts with interior strike hazards, by keeping occupants positioned correctly for maximum effectiveness of the airbag (if equipped) and by preventing occupants being ejected from the vehicle in a crash or if the vehicle rolls over.
When in motion, the driver and passengers are travelling at the same speed as the car. If the driver makes the car suddenly stop or crashes it, the driver and passengers continue at the same speed the car was going before it stopped. A seatbelt applies an opposing force to the driver and passengers to prevent them from falling out or making contact with the interior of the car (especially preventing contact with, or going through, the windshield). Seatbelts are considered Primary Restraint Systems (PRS), because of their vital role in occupant safety.
Seat belts were invented by English engineer George Cayley to use on his glider, in the mid-19th century.[5]
In 1946, Dr. C. Hunter Shelden opened a neurological practice at Huntington Memorial Hospital in Pasadena, California. In the early 1950s, Dr. Shelden made a major contribution to the automotive industry with his idea of retractable seat belts. This came about from his care of the high number of head injuries coming through the emergency room.[6] He investigated the early seat belts whose primitive designs were implicated in these injuries and deaths. To reduce the high level of injuries he was seeing, he proposed, in late 1955, retractable seat belts, recessed steering wheels, reinforced roofs, roll bars, automatic door locks, and passive restraints such as the air bag.[7] Subsequently, in 1966, Congress passed the National Traffic and Motor Vehicle Safety Act requiring all automobiles to comply with certain safety standards.
American car manufacturers Nash (in 1949) and Ford (in 1955) offered seat belts as options, while Swedish Saab first introduced seat belts as standard in 1958.[8] After the Saab GT 750 was introduced at the New York Motor Show in 1958 with safety belts fitted as standard, the practice became commonplace.[9] Seatbelts were not popular at first, with only 2% of Ford buyers choosing to pay for a seatbelt in 1956.[10]
Glenn Sheren, of Mason, Michigan, submitted a patent application on March 31, 1955 for an automotive seat belt and was awarded US Patent 2,855,215 in 1958. This was a continuation of an earlier patent application that Mr. Sheren had filed on September 22, 1952.[11]
However, the first modern three point seat belt (the so-called CIR-Griswold restraint) used in most consumer vehicles today was patented in 1955 U.S. Patent 2,710,649 by the Americans Roger W. Griswold and Hugh DeHaven.
Vattenfall, the Swedish national electric utility, did a study of all fatal, on-the-job accidents among their employees. The study revealed that the majority of fatalities occurred while the employees were on the road on company business. In response, two Vattenfall safety engineers, Bengt Odelgard and Per-Olof Weman, started to develop a seat belt. Their work was presented to Swedish manufacturer Volvo in the late 1950s, and set the standard for seat belts in Swedish cars.[12] The three-point seatbelt was developed to its modern form by Swedish inventor Nils Bohlin for Volvo-who introduced it in 1959 as standard equipment. In addition to designing an effective three-point belt, Bohlin demonstrated its effectiveness in a study of 28,000 accidents in Sweden. Unbelted occupants sustained fatal injuries throughout the whole speed scale, whereas none of the belted occupants were fatally injured at accident speeds below 60 mph. No belted occupant was fatally injured if the passenger compartment remained intact.[13] Bohlin was granted U.S. Patent 3,043,625 for the device.[8]
The world's first seat belt law was put in place in 1970, in the state of Victoria, Australia, making the wearing of a seat belt compulsory for drivers and front-seat passengers. This legislation was enacted after trialing Hemco seatbelts, designed by Desmond Hemphill (1926-2001), in the front seats of police vehicles, lowering the incidence of officer injury and death.[14] Mandatory seatbelt laws in the United States began to be introduced in the 1980s and faced opposition, with some consumers going to court to challenge the laws. Some cut seatbelts out of their cars.[10]