What must a heavy vehicle driver do before braking when descending a steep grade?

Before braking while descending a steep grade, a heavy vehicle driver must downshift to a lower gear. This technique utilizes the engine's braking power, which helps to slow down the vehicle more effectively and reduces the reliance on the brakes alone. This is crucial because braking on steep grades can lead to overheating, reduced braking effectiveness, and increased stopping distances, which can be dangerous.

Downshifting allows the driver to maintain better control over the vehicle's speed and provides additional braking force through the engine, which can prevent brake failure. As the vehicle descends, staying in a lower gear helps manage the speed without overstressing the braking system, ensuring a safer descent.