Yes, big rigs such as tractor-trailers, semis, semi-trailers, flatbeds, tankers and other 18-wheelers are involved in a disproportionate share of serious vehicle collisions in the U.S. According to the National Highway Transportation Safety Administration, large trucks represent 4 percent of registered vehicles, but they account for 8 percent of vehicles in fatal crashes. Because of the size of large trucks relative to other vehicles, when a truck accident occurs, typically the occupants of other vehicles receive the brunt of the injuries.