80. Why should you use chocks when parking a trailer without spring brakes?
Detailed Explanation
The correct answer is "b. Because if the air pressure leaks away or down, there will be no brakes.". This question tests controlled braking, heat management, and maintaining steering control. For a differently worded version of this question, identify the hazard first and then choose the answer that preserves control, visibility, or legal compliance.
Correct Answer: b. Because if the air pressure leaks away or down, there will be no brakes.
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 Combination Vehicles questions easier when the exam changes the wording.
Answer Review
Choose "b. Because if the air pressure leaks away or down, there will be no brakes." 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
- a. Because you don't want the trailer rolling down a hill."a. Because you don't want the trailer rolling down a hill." 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.
- c. Because some states require chocking of trailer wheels."c. Because some states require chocking of trailer wheels." 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 Combination Vehicles.
- 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
91. When should you use chocks to park a trailer not equipped with spring brakes?
96. A driver crosses the airlines when hooking up an old trailer with no spring brakes.
If a parked trailer does not have spring brakes, you should keep the trailer from moving by:
28. You are driving a combination vehicle when the trailer breaks away, pulling apart both air lines. You would expect the trailer brakes to come on and:
45. If the brakes are not released when you pushed the trailer air supply valve you should:
Keep Studying Combination Vehicles
Question pages help you review one rule at a time. To build test-day speed, move back into the full Combination Vehicles 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.