What is one of the uses of a converter dolly?

A converter dolly plays a crucial role in the operation of combination vehicles, specifically when linking multiple trailers. Its primary function is to couple two or three trailers behind a truck, enabling the safe and effective transport of large loads. The dolly connects the first trailer to the truck while providing a hitch point for an additional trailer, ensuring stability and weight distribution throughout the towing process.

While the other options suggest functions that may pertain to the trucking industry, they do not accurately describe the specific purpose of a converter dolly. For example, a converter dolly is not designed to store cargo during transit; storage typically involves different solutions like cargo compartments within trailers. Similarly, it does not function as an auxiliary brake system, as braking systems are integrated into the vehicle's design itself. Lastly, while aerodynamics is a significant consideration in truck design, a converter dolly is not specifically intended to enhance these properties. Thus, the dolly’s essential role in coupling trailers makes its primary use clear and distinct.