Why “Underride” Crashes Are So Deadly

When a passenger car strikes the side or rear of a tractor-trailer and slides beneath it, the consequences are often catastrophic. These are commonly called underride crashes. Because a trailer typically sits much higher off the ground than the hood of a car, the strongest safety structures in a passenger vehicle — the bumper, crumple zones, and engine block — can pass underneath the trailer entirely. Instead of absorbing the force of impact, the car continues forward until the trailer makes contact with the windshield and passenger compartment, the parts of the vehicle least able to protect the people inside.

The federal government has long recognized this danger. Rear underride guards have been required on most trailers for decades, and in recent years regulators and safety advocates have pushed for stronger rear guards and, more controversially, side underride guards. Side underride protection remains far less common, which is part of why a crash involving a trailer turning across or stopped in a travel lane can be especially severe. The Insurance Institute for Highway Safety has documented that underride collisions account for a meaningful share of the deaths in car-versus-large-truck crashes each year, and that improved guards could prevent many of them.

Large Trucks and Rural Highways in Georgia

Georgia sees a high volume of commercial truck traffic. As a freight corridor connecting the Port of Savannah to the rest of the Southeast, the state’s interstates and state routes carry an enormous number of tractor-trailers every day, including on two-lane rural highways like SR-57 where there are few barriers separating opposing lanes and limited room for a large vehicle to maneuver.

According to the National Highway Traffic Safety Administration, large trucks are involved in thousands of fatal crashes nationwide each year, and the people most likely to die are the occupants of the smaller passenger vehicles rather than the truck drivers. A loaded tractor-trailer can weigh 20 to 30 times more than a typical car and needs significantly more distance and time to stop or complete a turn. When a truck crosses or blocks a lane on an unlit rural road at night, oncoming drivers may have only seconds to react. Nighttime, limited lighting, and the sheer size differential all compound the risk in a crash like the one in McIntosh County.