What is the primary function of the coupling system in a truck-trailer combination?

The primary function of the coupling system in a truck-trailer combination is to securely connect the tractor to the trailer. This connection is crucial for ensuring that the two vehicles operate as a single unit while on the road.

A well-designed coupling system allows for a safe and reliable attachment that can withstand the stresses of transportation, including acceleration, deceleration, and turning movements. The coupling mechanism must maintain the connection even during dynamic operations, preventing the trailer from separating from the tractor and minimizing the risk of accidents.

While other aspects, such as fuel efficiency, stability during turns, and weight capacity, may be influenced by the overall design and operation of the vehicle, the core purpose of the coupling system is specifically to ensure that the tractor and trailer remain tightly and securely connected as they travel together. Thus, the correct answer reflects the fundamental role that the coupling system plays in the functionality and safety of truck-trailer combinations.