How should the lap belt be positioned for proper safety belt usage?

The lap belt should be positioned across the hips to ensure optimal safety during travel. This placement helps to secure the occupant's lower body and keep them firmly in the seat during sudden stops or collisions. When the lap belt is across the hips, it distributes the force of any impact over a larger area of the body, which minimizes the risk of injury to internal organs and allows the safety belt system to function as intended.

Positioning the belt across the stomach is unsafe, as it can lead to serious abdominal injuries in the event of a crash. Similarly, placing the belt across the shoulders is appropriate for the shoulder belt's placement but does not pertain to the lap belt, which specifically needs to anchor across the hips. Allowing the belt to rest loose behind the back negates its protective functionality and significantly increases the risk of injury, as it provides no restraint during an accident. Therefore, ensuring the lap belt is snugly and properly positioned across the hips is essential for maximizing safety in a vehicle.