Before starting downhill, which action is NOT recommended?

Answer: C — Accelerate quickly

Accelerating quickly before starting downhill is not recommended because it can lead to a loss of control over the vehicle. When descending a hill, it's crucial to maintain a safe speed to avoid overheating the brakes, which can happen if the driver allows the truck to gain excessive momentum. Instead of accelerating, the focus should be on downshifting, checking the brake system to ensure it's functioning correctly, and inspecting the load to make sure it isn't shifting, all of which contribute to the safe negotiation of a downhill slope. Maintaining a controlled and safe speed helps prevent accidents that can result from over-speeding when descending.