On the Making Light blog, novelist Jim Macdonald — who is also a paramedic — lays out the stark, grisly case for wearing your seatbelt. New Jersey’s Governor Jon S Corzine was recently badly injured in a car collision. He wasn’t wearing his seatbelt. The two other passengers in the vehicle were wearing their seatbelts — they sustained bumps and bruises. Macdonald’s description of what he sees when responding to “unrestrained passenger” accidents aren’t for the faint of heart. Macdonald may be a science fiction writer, but he missed a calling as a splatterpunk horror writer.
In a collision, you have three or four sub-collisions all taking place in sequence. First, the vehicle hits some object. The vehicle abruptly slows, but unrestrained objects inside it continue at the same speed, in the same direction. Then the unrestrained body hits the interior of the vehicle, and starts to slow. That’s the second collision. That body’s internal organs are still moving at speed until they hit the inside of the chest (or get cheese-sliced by their supporting ligaments–and that’s where you get things like bisected livers or aortas). The fourth collision is when the bowling ball you left on the rear deck hits you in the back of the head, because that continued at the same speed in the same direction. Newtonian physics: Learn it, live it, love it.