What is the primary purpose of seat belts?

The primary purpose of seat belts is to protect passengers during a crash. Seat belts are designed to secure occupants in their seats, preventing them from being thrown around or ejected from the vehicle in the event of a collision. By restraining the body's movement, seat belts significantly reduce the risk of serious injuries or fatalities. They work by spreading the forces of a crash across the stronger parts of the body, such as the chest and pelvis. This effectiveness is well-supported by numerous studies and safety statistics, indicating that wearing a seat belt drastically increases the chances of surviving an accident.

The other choices do not accurately represent the main function of seat belts. While keeping the car clean can be a minor benefit, it is not relevant to safety. Reducing vehicle speeds relates more to driving behavior than to seat belt function. Ensuring the driver is focused is important, but it refers to attentive driving rather than the protective role of seat belts during an accident.