What Are The Bars On The Back Of A Semi Called

The horizontal protective bars commonly seen at the rear of semi-trailers are usually called rear underride guards. They are also widely known as Mansfield bars, ICC bumpers or rear impact guards. Their purpose is to reduce the risk of a smaller passenger vehicle sliding underneath the trailer during a rear-end collision. Underride crashes are particularly dangerous because the trailer can intrude into the passenger compartment above the car’s main crash-protection structures. Federal safety standards regulate rear impact guards on many trailers in the United States, including requirements relating to their strength and position. Semi-trailers may also have other bars, rails or structural components, so the correct name depends on which part is being described. If you mean the prominent horizontal bar mounted low across the back of a trailer, “rear underride guard” is the technical description, while “Mansfield bar” is the commonly used name associated with the safety device.