Cadillac 2007 SRX Owner's Manual page 38

3. To make the lap part tight, pull up on the
shoulder part.
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 would 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 is a sudden stop or
a crash.
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