GMC 2011 Sierra Denali Owner's Manual page 66

3-12 Seats and Restraints
or the instrument panel... or the safety belts!
With safety belts, you slow down
as the vehicle does. You get more
time to stop. You stop over more
distance, and your strongest bones
take the forces. That is why safety
belts make such good sense.
Questions and Answers About
Safety Belts
Q: Will I be trapped in the vehicle
after a crash if I am wearing a
safety belt?
A: You could be whether you are
wearing a safety belt or not.
But your chance of being
conscious during and after an
accident, so you can unbuckle
and get out, is much greater if
you are belted. And you can
unbuckle a safety belt, even if
you are upside down.