2003 Chevrolet Avalanche Owner's Manual - Page 28

Q: What's wrong with this? You can be seriously injured if you wear the shoulder belt under yourarm. In a crash, your body would movetoo far forward, which would increase the chanceof head and neck injury. Also, the belt would apply too much force to the ribs, which aren't as strongas shoulder bones. You could also severely injure internal organs like your liver or spleen. A: The shoulder belt is worn under the arm. It should be worn over the shoulder at all times.