How should a truck-tractor's service brakes be tested?

• A. Drive forward slowly and stop
• B. Visual inspection
• C. Check the brake lights and fluid level
• D. Drive forward at a reasonable speed and pump the brakes a few times

Answer: (A)

The key idea is to verify braking performance by actually driving and stopping, not just inspecting components. By moving forward slowly and then stopping, you assess how the service brakes engage, how quickly the vehicle decelerates, and whether the stopping is smooth and even. This test reveals real issues like weak braking, brake imbalance, grabbing, or pulling to one side, which visual checks or fluid level lights wouldn’t show. Other options only look at indicators (like lights or fluid levels) or involve a procedure that doesn’t directly confirm how the brakes perform in real operation, so they can miss problems that affect stopping safety.