Pontiac None Aztek Owner's Manual page 36

The lap part of the belt should be worn low and
snug on the hips, just touching the thighs.
In a crash this applies force to the strong pelvic
bones. And you'd be less likely to slide under the lap
belt. If you slid under it, the belt would apply force at
your abdomen. This could cause serious or even
fatal injuries. The shoulder belt should go over the
shoulder and across the chest. These parts of the
body are best able to take belt restraining forces.
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