Underride Collisions and the Importance of Safety Guards

Due to the size, shape, and weight of semi-trucks and tractor-trailers, truck accidents are one of the most feared types of traffic accidents. As a result of its structure, when a truck is involved in an accident, it can create a variety of dangerous outcomes. From jackknives to rollovers, the potential for injury is extremely high. Unfortunately, one specific type of truck collision is ranked above all else in fatality risks: the underride collision.

Understanding the Underride Crash

An underride collision occurs when a passenger vehicle rear-ends a truck’s trailer and becomes wedged underneath it. Since trailer beds are raised higher than normal bumpers (approximately four feet from the ground), the space under the trailer is large enough to accommodate the front end of most vehicles. However, in the event of a rear-end collision the engine block isn’t the only part of the car that could wind up under the trailer. In fact, in many cases the force of the impact causes the front to slide under the trailer all the way up to the windshield, at which point the trailer’s edge sheers off the top of the car… and anything else in its way.

If the victims in the car are very lucky, then the impact force will have dissipated before the edge of the trailer reaches them. Otherwise, bone is no match for 80,000 pounds of sharp metal moving at speeds of up to 60 miles per hour. Decapitations are frightfully common in underride accidents.

Now considering the catastrophic effects of such accidents, don’t you think there should be a way to lessen the risks of such a tragedy? The Insurance Institute of Highway Safety (IIHS) thought as much when it petitioned the National Highway and Traffic Safety Administration to implement better underride safety standards with mandatory underride guards.

Bereavement Barriers: Underride Guards and How They Protect Against Fatal Truck Collisions

Have you ever passed a truck and wondered why there was a metal bar hanging about two feet below the back end of the trailer? Is it a step? Is it a type of hitch for more trailers?

Actually, it’s a safety rail.

As a result of the IIHS’s efforts, semitrailers are required to have these metal bars, also known as underride guards, in order to help decrease fatal underride collisions. The guards are made of steel and are attached below the rear end of the trailers. The purpose of these bars is threefold: they act as barriers, absorb impact force, and prevent impact force from violently pushing cars underneath the trailer.

  • Vehicle barriers. Because the bars are placed at a lower level than the trailers themselves, they prevent the front end of passenger vehicles from continuing under the trailer unimpeded. Essentially, they act as a barricade between your car and the open space under the trailer.
  • Stopping blocks. When guards are placed on the same level as a passenger vehicle’s axis, then even if the force of an accident were to push the car forward, the guard will prevent it from moving further underneath the trailer. The guards basically provide a block for your car’s bumper—structurally, the strongest part of your car’s frame—to hit first, thus stopping the car from continuing forward.
  • Impact absorber. Without an underride guard, the main structures that would help absorb force of an impact (the car’s front bumper, engine block, and front axle) are completely bypassed as they slide under the trailer. This means the majority of the collision force will dissipate through the car’s upper compartment, where the trailer will sheer off and crush the windshield, roof, and everything in between. However, when the truck has steel guards for the bumper and engine block to hit, the impact force will be exerted where it can be managed—at the front of car.

So, the next time you pass a truck, you may want to take a second to appreciate the importance of a simple metal bar.

For more information about truck safety, or if you or a loved one has suffered a tragic truck collision, contact us today at 210-340-8877 for a free consultation. Let us help guard your future and get you and your family the recovery and peace of mind you need.