Chevrolet 2007 Monte Carlo Owner's Manual page 38

3. Be sure that the belt is not twisted and it lies
flat. The elastic cord must be under the belt
and the guide on top.
38
CAUTION:
{
A safety belt that is not properly worn
may not provide the protection needed
in a crash. The person wearing the belt
could be seriously injured. 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.