When should you downshift a commercial vehicle?

Answer: D — Both before starting downhill and before entering a curve

Downshifting a commercial vehicle is an important skill for maintaining control and safety while driving, particularly in challenging situations. When you downshift before starting downhill, it helps to use the engine's braking power to control speed, reducing reliance on the brakes, which can overheat and lead to brake failure. This proactive approach enhances safety and stability as the vehicle descends. Similarly, downshifting before entering a curve is crucial for maintaining speed control and vehicle balance. By selecting a lower gear, you allow the vehicle to have better traction and responsiveness while navigating the turn, which is vital for preventing skidding or losing control. Thus, downshifting before both starting downhill and before entering a curve ensures that the driver can effectively manage speed and enhance safety during these critical driving scenarios.