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.
Detailed Explanation
After selecting the proper low gear, apply the brakes firmly enough to feel a definite slowdown. When the vehicle reaches about 5 mph below the safe speed, release the brakes and let speed increase before repeating the application. This avoids riding the brakes continuously and helps control heat.
Correct Answer: 5
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
The correct answer is 5 mph below the safe speed. This controlled application-and-release method preserves braking capacity on a long or steep downgrade.
Why the other answers are weaker
- 10"10" does not best answer this transmission types and gear selection 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.
- 15"15" does not best answer this transmission types and gear selection 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.
Ready to practice for real?
Take our free, full-length Air Brakes practice test. Simulates the actual DMV exam with timed questions.
Start Practice TestRelated Questions
While driving downhill, you should brake until you reach a speed that is ____ below your safe speed, then release the brake pedal.
89. You are on a steep down grade and have reached your safe speed of 40 mph. You would apply the service brakes until your speed drops to - mph.
4. To make an emergency stop with air brakes, using the stab braking method, you should:
65. The use of brakes on a long steep downgrade is only a supplement to the braking effect of the engine.
If braking at a speed of 55 mph while driving on dry pavement, the brake lag can add ____ to your vehicle's total stopping distance.
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.