GMC 2010 Acadia Owner's Manual page 78

3-24 Seats and Restraints
Q: What is wrong with this?
A: The belt is behind the body.
WARNING
You can be seriously injured by
not wearing the lap-shoulder belt
properly. In a crash, you would
not be restrained by the shoulder
belt. Your body could move too
far forward increasing the chance
of head and neck injury. You
might also slide under the lap
belt. The belt force would then be
applied right on the abdomen.
That could cause serious or fatal
injuries. The shoulder belt should
go over the shoulder and across
the chest.
Q: What is wrong with this?
A: The belt is twisted across
the body.