Underride: The Truck Crash We Already Know How to Prevent
Engineers figured out how to stop these decades ago. They keep happening anyway. There is a kind of truck crash that is worse than the physics of an ordinary collision, and once you understand it, you notice trailers differently on the highway. It is called underride, and it is exactly what it sounds like. In a normal crash, a car's bumper hits the other vehicle's bumper. The frame, the crumple zones, and the airbags all do their job at roughly the height they were designed for. Underride throws that out. The car slides under the trailer instead of stopping against it, and the impact lands where the windshield and roofline are, not where the bumper is. The parts of the car built to protect people never get the chance. Rear guards help. Side guards barely exist. Federal rules require trailers to carry a rear underride guard, the steel bar you see hanging beneath the back of a trailer. Done right, it stops a car before it slides under. The trouble is what happens on the...