Cooley On Cars
Smarter Driver: Avoiding underride accidentsYou don't want to get into any kind of accident, but especially a rear underride with a semi, which is able to defeat many of the safety advances of the last few decades.
-Ninety-four percent of the fatalities that occur when cars and trucks tangle are people in the car. Duh. And one of the nastiest kinds of those accidents is the rear underride -- when you slam into the back of one of those big semi-trailers. A collision so nasty, it became this iconic scene in that movie from the early '70s, The Seven-Ups. You see that one with Roy Scheider? That scene doesn't leave your memory very quickly. You don't wanna get into one of those. Luckily, if you do happen to rear end a semi these days, there's almost certainly gonna be this big bar that hangs down on two uprights. You've seen these at the underride guard. And then, it will keep your car largely from submarining underneath the vehicle. But if you hit one dead on from the rear, odds are pretty good your car's front crumple zone is going to engage it and that's going to largely protect you inside your vehicle. -The Federal Government requires that the backs of semi-truck trailers have underride guards to prevent vehicles from sliding underneath them in the event of a crash. -Plus, those guards vary widely in strength. There's not a really good high standard across the industries. Some trailer makers build a real tough. Others don't and they collapse far too easily. -The weakest underride guarding I tested here was on a Hyundai trailer. When this Malibu struck the Hyundai in the rear in a center impact at 35 miles per hour, the guard was simply pushed out of the way. The attachment bolts broke. The damage to the Malibu was so severe that real people in this crash probably would have died. -Now, while about 12 percent of car-truck fatalities are underride rear-end collisions, there's a whole big risk of side underride if you come broadside under a trailer or hit that at like a 45 degree. Even at speeds as slow as 35 miles an hour, cars often submarine under the side of the underride guard. And that's much rare to see the kind of guards that prevent that. They're much more common in Europe. Now, things have been getting a lot better on those underride guards. First of all, they used to be required to be, I think, 60 inches wide. Now, I believe they have to be at least 94 inches wide up to, I think, 110 inches. So, there's a lot more width there to find the sweet spot. And while many of the trailer manufacturers are doing a better job of voluntarily making them stronger, there's been a petitioning of the Federal Government by the insurance industry to adopt the tougher Canadian standard that dates back to 2007, but again, it's not mandatory in the U.S. And some big trucks don't have an underride guard at all because of the mechanical complexity of it. Look at a dump truck, for example, because the bed has to tilt, the underride guard would get in the way and clip the ground or the wheels, similar for some of those big dump trailer semis you see. So, here's what the Smarter Driver does. You allow more space as you're about to make a lane change out from behind the semi because the problem is as you're turning to look for a clear lane, what if that truck slows down a lot? Suddenly, you're starting your lane change, he's stopping down, and you take a glancing blow on that underride guard. It's the one you don't wanna have.