A few years ago, my wife was in a head-on collision, not of her creation. She was driving a Pontiac minivan. The LEO's at the scene said if it weren't for the air bag and belts she couldn't have survived.
She walked away from it at the time, but a week later she had a stripe from the top of her left shoulder to her right hip, and across the front of her abdomen, about 5" wide and the darkest purple I've ever seen on anyone. Obviously caused by the belts.
They took her to the ER of our local hospital to check her over right after the accident, and the doctor told her that in about a week she would be more sore all over than she had ever been in her life. He was right.