More mass doesn't just help when you hit other cars. It also helps when you, say, run into a wall. Or a moose. The more mass you've got, the slower anything tha

More mass doesn't just help when you hit other cars. It also helps when you, say, run into a wall. Or a moose. The more mass you've got, the slower anything that hits you can reduce your speed, the less harm that the sudden deceleration does to you.