CDL Tanker Endorsement Practice Exam

When stopping a tanker downhill, which technique is most effective?

1. Applying brakes constantly

2. Using engine braking combined with service brakes

3. Using the emergency brakes only

4. Coasting to a stop

The correct answer is: Using engine braking combined with service brakes

Using engine braking combined with service brakes is the most effective technique when stopping a tanker downhill for several reasons. When you're navigating downhill, the weight of the tanker can create significant momentum, making it easy for the vehicle to gain speed rapidly. Engine braking utilizes the engine's resistance to help slow the vehicle down, which is particularly beneficial in maintaining control and preventing overheating of the braking system. This technique involves downshifting to a lower gear, allowing the engine to slow the vehicle while maintaining a safer speed. Combining engine braking with service brakes enhances braking efficiency. Service brakes can then be applied judiciously to fine-tune the vehicle's speed without relying solely on them, which can lead to brake fade if they are continually engaged. By using this combination, the driver can help keep the braking system cooler and prolong its effectiveness, especially in a downhill situation where excessive brake use can lead to brake failure. Together, this combination allows for better control of the tanker and reduces the risk of losing control due to excessive speed, making it a safer practice when descending inclines.