2003 Buick Century Owner's Manual - Page 11

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 likethis. The shoulder belt can't do its job because it won't be against your body. Instead, will be it in front of you. In a crash you could go into it, receiving neck or other injuries. 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. 3ut don't have a seatback reclined if your vehicle is moving. 1-4