Explain how to properly ascend a steep hill in a commercial vehicle.

Shifting to a lower gear when ascending a steep hill in a commercial vehicle is important for maintaining both power and control. When climbing a steep incline, the engine needs to work harder to overcome the gravitational force pulling the vehicle backward. In a lower gear, the engine can operate at a higher RPM, which provides more torque — essential for climbing steep grades effectively. This also helps prevent the engine from stalling, as it allows for better acceleration and the ability to maintain your speed without losing power.

Additionally, using a lower gear provides better stability and traction. In steep situations, having control over your speed and minimizing the risk of losing momentum or rolling backwards is crucial. In contrast, maintaining the same gear used on flat roads can result in insufficient power, making it harder to climb the hill safely and efficiently. Driving in the highest gear may save fuel in other driving conditions, but it can compromise performance on an incline. Accelerating rapidly as you climb can lead to loss of traction, especially if the surface is slick or the weight of the vehicle exceeds the tire's grip on the road.