Commercial Driver License (CDL) Class B Practice Test

What is the correct braking technique when descending a steep downgrade?

1. Brake hard continuously until stopped

2. Lightly apply brakes to slow down, then release

3. Use engine braking exclusively

4. Brake only if you feel an emergency

The correct answer is: Lightly apply brakes to slow down, then release

The correct braking technique when descending a steep downgrade involves lightly applying the brakes to slow down, then releasing them periodically. This approach helps to maintain control of the vehicle while preventing overheating of the brakes. Continuous hard braking can lead to brake fade, where the brakes become less effective due to excessive heat, potentially resulting in a loss of control. Using engine braking is also a crucial aspect of controlling speed on steep descents. By shifting to a lower gear, the engine helps slow down the vehicle without putting as much strain on the brake system. However, relying solely on engine braking may not always provide sufficient control depending on the slope's steepness and the weight of the vehicle. Simply braking only in an emergency neglects the proactive measures needed to manage speed on descents. This could lead to dangerous situations if the driver does not adjust their braking before an urgent need arises. Therefore, the method of lightly braking and then releasing allows for a balance between effective speed control and brake system preservation.