What is a dead axle on a truck?

A deadhead truck has a trailer attached but carries no freight. Deadheading means driving a cargo carrying truck (semi-truck) pulling an empty trailer. Deadheading often happens when a trucker returns or backhauls the empty cargo container to the point of origin. Be careful not to confuse “deadheading” with “bobtailing,” which happens when driving a cargo carrying truck without a trailer attached.