2003 GMC Safari Owner's Manual - Page 31

Q: What's wrong with this? You can be seriously injured if youwear the shoulder belt under your arm. In a crash, your body would move toofar forward, which would increase the chance of head and neck injury. Also, the belt would applytoo much force to the ribs, which aren't as strong as shoulder bones. You could also severely injure internal organs like your liver orspleen. A: The shoulder belt is worn under the arm. It should be worn over the shoulder at all times. 1-24