seatbelt

A seatbelt is a vehicle restraint designed to secure an occupant and reduce injuries in crashes. It typically comprises a webbing strap anchored to the vehicle structure, a buckle for locking the strap in place, and a retractor that tightens during sudden deceleration.

The modern three-point seatbelt was invented by Nils Bohlin for Volvo and introduced in 1959. It became widely adopted in the 1960s and has since been mandated in varying degrees around the world for drivers and front-seat passengers; many places extend requirements to all seating positions.

Types and features: The most common form is the three-point belt that restrains the torso and hips. Some vehicles still use lap belts (two-point) in older or special configurations. Modern belts may include pretensioners that tighten during a crash and load limiters that allow a controlled amount of belt slack to reduce chest load. Child safety seats and booster cushions are used with belts for younger passengers.

Function and effectiveness: Seatbelts reduce the risk of head, chest, and spinal injuries by keeping occupants inside the vehicle and distributing crash forces across the strongest parts of the body. They substantially reduce fatalities and serious injuries, especially for front-seat occupants, and are most effective when used in combination with airbags and other restraints.

Usage and standards: In many countries, belt use is required by law for front seats and increasingly for all seats. Standards include FMVSS 208 in the United States and ECE Regulation 16 in Europe. Proper fit means the belt lies across the pelvis and shoulder, not the neck or face, with no twisting or underarm placement.

Maintenance and limitations: Regularly check webbing for wear or damage and ensure the retractor locks smoothly. Belts should be replaced after a crash or if damaged. They are a critical element of protection but do not prevent injury on their own.