What is the primary function of a seat belt in a vehicle?

The primary function of a seat belt in a vehicle is to secure occupants and prevent ejection from the vehicle during a collision. Seat belts are designed to restrain the motion of the body in the event of sudden deceleration or impact, effectively reducing the chances of injury. When a vehicle is involved in an accident, the seat belt helps to keep the occupant in their seat, minimizing the risk of being thrown against the interior of the vehicle or ejected from it altogether. This protective measure significantly increases the chances of survival and reduces the severity of injuries sustained in accidents.

While the other options may imply certain benefits, they do not capture the fundamental safety purpose of a seat belt. For instance, seat belts do not play a role in maintaining alertness while driving, restricting vehicle movement, or enhancing aesthetic appeal. Their primary and critical purpose is focused on passenger safety.