A seatbelt spreads the stopping force needed to decelerate the passenger across their body. This prevents the body from hitting the windshield or steering column of a car at high speed, which could easily result in injury or death.
How do seat belts keep you in place?
The basic idea of a seat belt is simple. Wearing a belt keeps passengers from being ejected from a vehicle in a crash. Because three point belts spread the force across more of the body than two point belts, they minimize the strength of the force in one area, minimizing injury.24 Jun 2017
What causes a seatbelt to lock up?
The first system relies on a pendulum with a weight on the bottom. This pendulum is below the spool that your seatbelt wraps around. When your car stops abruptly the force causes the weight on the bottom to move forward quickly. This causes the top of the pendulum to move backwards and lock into the teeth of the spool.27 Jul 2017
Do seatbelts lock after a crash?
In the unfortunate event of a collision, seatbelts help protect the occupants from injury. During a collision, the airbag computer initiates the seatbelt igniter to ignite, activating the seatbelts and locking them into position around each occupant wearing the seatbelt.6 Sept 2017