Is it true that using brakes on a long downgrade is only a supplement to the engine braking effect?

The statement that using brakes on a long downgrade is only a supplement to the engine braking effect is accurate and highlights an important principle of safe driving, especially for commercial drivers. Engine braking, which utilizes the engine’s resistance to slow down the vehicle, can help maintain control and reduce wear on the brake system during extended descents. It is an essential technique for managing speed, particularly when navigating steep grades.

Brakes should be utilized to assist in controlling speed, especially in a heavy vehicle, but relying solely on mechanical brakes can lead to overheating and potential brake failure. Therefore, the brakes should complement engine braking rather than replace it. This ensures that the driver maintains control of the vehicle and extends the life of the brake components through less frequent and less intense use.

In contrast, the other options imply scenarios where reliance on brakes might be the only method for descending, which undermines the principles of safe driving on downgrades. The context for effective downhill driving emphasizes the need for a collaborative effort between engine braking and the use of service brakes, making the correct answer significant for the safety and efficiency of handling large vehicles.