The lap belt should be adjusted so that it is:

The lap belt should be adjusted so that it is snug, lying low across your hips. This positioning is crucial for safety during a vehicle crash. When the lap belt is low and tight, it helps to distribute the force of an impact across the stronger parts of your body, such as your pelvis. A properly adjusted belt reduces the risk of injuries significantly by ensuring that your body stays in place during sudden stops or collisions.

In contrast, if the lap belt is too loose, it may not provide effective restraint during an accident, increasing the likelihood of sliding under the belt (known as "submarining"). Additionally, if the belt is adjusted incorrectly or does not cover the proper area, it can lead to injuries to the abdomen or other vital areas of the body. Therefore, ensuring that the lap belt fits correctly is essential for maximizing safety in a vehicle.