Crash test reveals when hitting a semi truck head-on may save your life
You’d think swerving at the last second to avoid a crash would be the smart move. But with semi trucks, that instinct could kill you. The Insurance Institute for Highway Safety (IIHS) just revealed that hitting the center of a trailer’s rear bumper may be safer, while grazing the edge is usually deadly.
Most trailer guard edges can’t handle a crash
The IIHS crash-tested trailers from eight major manufacturers at 35 mph. Every semi truck trailer stopped a car that struck it head-on. But when the car didn’t strike the trailer head-on, it slid under the trailer in a phenomenon known as “underride.”
That means the front crumple zone never activates—and the trailer hits the car right at head level. And that’s not a scenario many folks walk away from.
But in tests with 50 percent and narrower overlaps, most failed. “All but one prevented underride in the fifty percent overlap condition,” David Zuby, IIHS Chief Research Officer. Only one trailer passed the narrow overlap test without “killing” the test dummies.
Zuby put it plainly: “Our research shows the cars are still vulnerable to underride when they hit the outer end of the bar.”
One semi truck trailer is a bit safer
Only one trailer survived all three tests. That was the Manac, which sells under the Trailmobile brand. “The Manac engineers tried something different,” the Zuby said. “They moved the vertical supports outboard, which makes the ends of the guard stronger.”
Other trailers place the guard’s support bars closer to the center. That design leaves the corners exposed—and weak.
“All of the trailers in this series of tests had guards that met Canadian standards,” Zuby notes. But even that higher standard isn’t enough to stop underride during a corner hit.
Your car’s front end is built to crumple and protect you—but it only works if you hit something solid. The IIHS tests make one thing clear: semi truck trailer guard strength varies, and the outside edge is often the weakest link. If a crash is inevitable, you may want to aim for the strongest part of a semi truck trailer: the center. See the crash tests yourself in the video embedded below:
