What does the term 18-wheeler refer to?

A) any transport truck
B) single drive axle tractor and dual axle trailer
C) dual drive axle tractor and dual axle trailer
D) dual drive axle tractor and B-train combination

Dual Drive Axle

A vehicle axle configuration featuring two drive axles which provide additional power for traction, commonly seen in heavy-duty trucks.

18-Wheeler

A large trucking rig composed of a tractor unit and a semi-trailer, which together have a total of 18 wheels, commonly used for long-haul transport.

B-Train Combination

A tractor-trailer configuration consisting of a lead trailer followed by a second trailer, connected by a fifth wheel mounted on the rear of the first trailer.