Seat belt use cuts serious and fatal car crash injuries by half. The National Highway Traffic Safety Administration estimates that safety belts save 13,000 lives every year. However, a defective seat belt fails to provide protection or may even increase the chances of injuries.
How Seat Belts Are Supposed to Work
A seat belt works by holding your body in place during a collision. If your car were traveling at 30 mph, for example, and hit a stationary object, your car would stop upon impact, while your body continued traveling at 30 mph until you hit an object, such as the steering wheel or windshield.
The seat belt, however, stops the momentum of your body from continuing forward at a high rate of speed. The wide strap puts even pressure on your relatively sturdy pelvis and ribcage, to protect the vulnerable parts of the body, such as your head, spinal cord and face. Furthermore, the flexible webbed material is designed to cushion the movement and more gradually stop your body.
The spool and retractor mechanism allows you to stretch the seat belt far enough to buckle it and keeps the strap comfortably snug against your body. The loss of the car’s forward momentum, as occurs if your car hits an object or you slam on your brakes, engages a locking mechanism that tightens the seat belt.