The car decelerates. Even at 50 kph you leave your seat and your head hits the windscreen.
This will cause damage to the brain cells and can cause severe spine and other head injuries. It may cause other injuries including punctured lungs and fractures to your limbs. The injuries yousustain are such that you are unlikely to recover fully.
You also hit the other occupants of the car causing them injury.
Why would you get into car without putting on a seatbelt?
