How can a driver ensure that the fifth wheel is fully locked and engaged with the kingpin when coupling a trailer?

To ensure that the fifth wheel is fully locked and engaged with the kingpin when coupling a trailer, performing a TUG test by moving the tractor forward is the most effective method. This procedure involves gently pulling forward with the tractor after the trailer has been connected. By doing this, the driver can feel if the coupling is secure. If the fifth wheel is properly locked onto the kingpin, there will be resistance as the tractor moves, indicating that the connection is stable.

While visually inspecting the coupling is important for a general check, it does not provide the physical confirmation that the TUG test does. Simply turning the steering wheel or using reverse gear may not effectively demonstrate whether a secure connection has been achieved, as these actions do not apply the necessary force to confirm that the fifth wheel is fully engaged. Therefore, the TUG test is a critical step in the coupling process, ensuring safety and stability on the road.