GMC Express 2011 Owner's Manual page 61

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 on 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 shoulder belt locks if there is a
sudden stop or crash.
Q: What is wrong with this?
A: The shoulder belt is too loose.
It will not give as much
protection this way.
Seats and Restraints
WARNING
You can be seriously hurt if the
shoulder belt is too loose. In a
crash, you would move forward
too much, which could increase
injury. The shoulder belt should fit
snugly against your body.
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