GMC YUKON DENALI 2000 Manual page 44

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.
The safety belt locks if there's a sudden stop or a crash.
Each position next to the windows has a shoulder belt
height adjuster. Move the shoulder belt height adjuster
to the height that is right for you.
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