1996 GMC Safari Owner's Manual - Page 12

A CAUTION: Sitting in a reclined position when your vehicle is in motion can be dangerous. Even if you buckle up, your safety belts can't do their job when you're reclined like this. The shoulderbelt can't do its because it job won't be against your body. Instead, it will be in front of you. In a crashyou could go into it, receiving neck or otherinjuries. The lap belt can't do its job either. In a crash the belt could go up over your abdomen. The belt forces would be there, not at your pelvic bones. This could cause serious internal injuries. For proper protection when the vehicle is in motion, have the seatback upright. Then sit well back in the seat and wear your safety belt properly. But don't have a seatback reclined if your vehicle is moving. 1-4