Tractor trailers must meet federal regulations set by the National Highway Traffic Safety Administration and the Federal Motor Carrier Safety Administration. Some safety features, such as rear underride guards, are mandatory.
Side underride guards are not yet a part of the required safety equipment on trucks. However, according to the Insurance Institute for Highway Safety, they should be.
The size, weight and high ground clearance of large trucks put the drivers at much lower risk of harm in a crash. At the same time, these factors increase the chances that people in passenger vehicles will sustain serious or fatal injuries.
The most recent U.S. statistics illustrate this. In accidents involving large trucks in 2015, 1,542 passenger vehicle occupants died. Of those fatal injuries, 301 occurred when vehicles collided with the side of sem itrucks. Rear-impact crashes killed 292 people that year.
The average trailer is 53 feet long, and with no guard, underride could happen along 72 percent of that length, or just over 38 feet. Although a side underride guard does not cover the entire lower portion between the wheels and the connection with the truck, it reduces the exposed length to about 20 feet.
In crash tests IIHS researchers performed, when a typical sedan traveling at 35 mph hits the side of a trailer without an underride guard, the crumple zones are unable to absorb the impact. Instead, the vehicle keeps moving forward, sliding under the trailer, which scrapes off the windshield and top half of the car. Most real-life crashes under these conditions cause fatal injuries.
When researchers perform those same crash tests, but with side underride guards on the tractor trailers, a car strikes nose first and stops. As in any collision, the crumple zones lessen the force of the crash, the airbags deploy and passengers wearing proper restraints may only have minor injuries.
Some cities have enacted their own restrictions requiring truck owners to install side underride guards, but safety experts have proposed federal laws that would increase safety for everyone on America’s roadways.