Anyone who has driven on an Interstate highway has undoubtedly wondered about the horizontal bar on the rear of semi-trailer trucks. Why is it there? What does it do? The bars are called underride protectors or rear guards, and they are supposed to prevent passenger vehicles from sliding under the truck in the event of a rear-end collision. As a recent accident in Charlotte demonstrates, they do not always fulfill their function.

Sometimes, underride bars do not accomplish their intended purpose. According to reports, a 23-year old woman was recently killed in an underride collision in Charlotte when her car slid under a semi-trailer that was stopped in traffic. Police attributed the accident to failure to reduce speed, but other data shows that the blame for the death may be shared by other parties. Tests of underride bars conducted by the Insurance Institute for Highway Safety have demonstrated that underride bars do not always prevent serious accidents, even if they are designed to withstand speeds up to the legal maximum of 35 mph.

Underride guards are required on trailers and semi-trailers by regulations promulgated by the National Highway Traffic Safety Administration and similar agencies in a number of states. The guards are intended to protect drivers and passengers in sedans if they should collide with the rear end of the truck. The bar is supposed to stop the vehicle before it slides under the body of the truck.

The number of fatal underride crashes appears to be increasing every year. In 2016 and 2017, the last years for which data are available, the number of fatal underride crashes increased from 347 to 398. Anyone who has been injured or lost a loved one in an underride crash may wish to consult an experienced personal injury attorney for an analysis of the evidence and an estimate of the likelihood of recovering damages for medical expenses, lost income and pain and suffering.