When driving downhill on a mountain road, what should you do to help control your speed?

When driving downhill on a mountain road, shifting to a low gear is an effective strategy to help control your speed. By selecting a lower gear, the engine can provide the necessary braking assistance, known as engine braking, which slows the vehicle down without relying solely on the brakes. This method is particularly important in mountainous areas where prolonged brake use can lead to brake overheating and reduced braking efficiency.

Utilizing engine braking allows the vehicle's natural resistance from the engine to help manage speed, making it a safer option. It ensures that the brakes are not overworked, thus reducing wear and providing more control over the vehicle's speed as it descends.

In contrast, using higher gears or accelerating would increase speed, while constantly using the brakes could lead to brake failure due to overheating. Therefore, shifting to a low gear is crucial for both safety and maintaining control of the vehicle when traveling downhill.