What is the primary purpose of seat belts?

The primary purpose of seat belts is to reduce injury in the event of an accident. When a vehicle comes to a sudden stop, such as in a crash, occupants inside the vehicle experience inertia, which can cause them to continue moving forward at the same speed the vehicle was traveling. Seat belts effectively restrain the occupants, helping to distribute the forces of a collision across stronger parts of the body and preventing them from being thrown forward or ejected from the vehicle. This significant reduction in movement helps to lessen the severity of injuries that can result from accidents, making seat belts a critical safety feature.

While keeping passengers in the car is a function of seat belts, it is secondary to the primary goal of injury reduction. The focus of seat belt design and enforcement is on safety outcomes during collisions, rather than merely preventing occupants from leaving the vehicle. Compliance with safety regulations is indeed important for legal and safety standards, but it is an aspect of broader safety practices rather than the primary role of a seat belt. Preventing distractions for the driver is not relevant to the design or intended use of seat belts. They are primarily about protecting the occupants during a vehicle crash situation.