65. The use of brakes on a long steep downgrade is only a supplement to the braking effect of the engine.
Detailed Explanation
The correct answer is "True". This question tests controlled braking, heat management, and maintaining steering control. Absolute words such as "always," "never," and "only" deserve a careful second reading because one missing condition can make an option wrong.
Correct Answer: True
Why This Matters on the CDL Test
This question belongs in your brake safety review. Pay close attention to pressure limits, inspection steps, stopping distance, and warning signs because brake-system mistakes are a common reason CDL applicants miss endorsement questions.
How to Remember It
Say the rule in your own words, then explain why the wrong answers are unsafe or incomplete. That habit makes similar Air Brakes questions easier when the exam changes the wording.
Answer Review
Choose "True" because this answer matches the safe CDL action for brake system safety. On the knowledge test, the safest answer is usually the one that protects space, control, visibility, legal compliance, or inspection accuracy before the vehicle is put at risk.
Why the other answers are weaker
- False"False" does not best answer this brake system safety question. When you see a similar option on the CDL permit test, compare it against the exact safety rule and choose the answer that prevents the most immediate risk.
Test-Day Checklist
- Read the question once for the topic, then read it again for the exact CDL action being tested in Air Brakes.
- Eliminate answers that sound convenient but skip an inspection, warning sign, or safety step.
- Say the correct rule out loud before moving on so you can recognize it when the exam changes the wording.
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Start Practice TestRelated Questions
38. The proper method of braking when going down a long and/or steep grades after selecting the proper gear, is to brake until your speed is about _ miles per hour below your 'safe' speed, then release your brakes.
87. The use of air brakes on a downgrade is only a supplement to the:
20. The braking power of the spring brakes:
3. The air brake system for a straight truck or bus should not leak at a rate of more than______ psi per minute with the engine off and the brakes released.
4. To make an emergency stop with air brakes, using the stab braking method, you should:
Keep Studying Air Brakes
Question pages help you review one rule at a time. To build test-day speed, move back into the full Air Brakes practice test and answer a mixed set without looking at the explanation first.
State CDL Practice Paths
After you understand this answer, use a state practice path to connect the federal CDL rule with the DMV test pages drivers search for most.