Vehicle Equipment & Safe Operation — Maine
Maine CDL practice test: 373 free practice questions (Based on the official driver handbook). The official format is not yet verified; check the official site before your test. Vehicle Equipment & Safe Operation: 135 questions.
Brakes, tires, lights, mirrors, seat belts, child seats and basic vehicle control.
This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines.
| Topic / Metric | Value |
|---|---|
| Topic | Vehicle Equipment & Safe Operation |
| License test | Maine CDL permit (CLP) knowledge tests |
| Topic questions | 135 (36% of 373 total) |
| Review status | This topic page is still being reviewed against the official handbook. Until review is finished it is hidden from search engines. |
Official handbook
Not yet verified
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Questions (135)
1. If the emergency air line loses pressure:
- The service brakes will activate.
- The tractor protection valve will close. ✓
- The rear trailer will detach from the combination.
Answer: B. The tractor protection valve will close.
The tractor protection valve will close when the emergency air line loses pressure. The handbook says the tractor protection valve keeps air in the tractor when a trailer breaks away or has a bad leak. It closes by itself when air pressure drops, stopping air from leaving the tractor and letting air out of the trailer emergency line. That release brings on the trailer emergency brakes. So a low-pressure emergency line points to the tractor protection valve closing, not to service brakes or trailer separation.
2. Vehicles equipped with Anti-Lock Braking Systems (ABS) have ____ malfunction lamps to indicate when the ABS is not working.
- Green
- Blue
- Yellow ✓
Answer: C. Yellow
The ABS malfunction lamps are yellow. The handbook says vehicles with ABS have yellow malfunction lamps that tell you if something is not working. It also says tractors, trucks, and buses have these yellow ABS lamps on the instrument panel, while trailers have them on the left side, front or rear corner. That direct description of the lamp color supports choosing yellow for the malfunction lamp.
3. If the emergency air line loses pressure:
- The Anti-Lock Braking System will activate.
- The service air line will activate.
- The emergency brakes will activate. ✓
Answer: C. The emergency brakes will activate.
If the emergency air line loses pressure, the emergency brakes will activate. The emergency line does two jobs: it supplies air to the trailer tanks and it controls the trailer emergency brakes. When pressure in that line drops, the trailer emergency brakes come on. The handbook also notes that a major leak in the emergency line can close the tractor protection valve and apply the trailer emergency brakes. The Anti-Lock Braking System and the service line are not described as activating because the emergency line lost pressure.
4. The parking brake in a newer vehicle is applied by:
- Moving a lever to the right.
- Pushing a yellow, diamond-shaped knob.
- Pulling a yellow, diamond-shaped knob. ✓
Answer: C. Pulling a yellow, diamond-shaped knob.
In a newer vehicle, you apply the parking brake by pulling the yellow, diamond-shaped knob. The handbook's air brake section says that in newer vehicles with air brakes, the parking brake control is a yellow, diamond-shaped push-pull knob. You pull it out to apply the parking brakes and push it in to release them. The same section notes that older vehicles may use a lever instead. So the action that sets the brake on a newer vehicle is pulling that yellow knob.
5. Brakes out of adjustment will:
- Work properly.
- Cause some of the brakes to overwork and malfunction. ✓
- Allow better acceleration.
Answer: B. Cause some of the brakes to overwork and malfunction.
6. Braking mechanisms are located inside:
- The fifth wheel.
- A brake drum. ✓
- The landing gear.
Answer: B. A brake drum.
The braking mechanism is located inside a brake drum. The handbook describes foundation brakes at each wheel and names the s-cam drum brake as the most common type. It says brake drums sit on each end of the vehicle's axles, the wheels are bolted to them, and the braking mechanism is inside the drum. To slow the vehicle, the brake shoes and linings are pushed against the inside of the drum, creating friction. That direct description points to the brake drum as the place where the braking mechanism is housed, not to other vehicle parts.
7. Having ABS on only one axle:
- Can be dangerous.
- Still allows you additional control when braking. ✓
- Slows the vehicle, but cannot stop it.
Answer: B. Still allows you additional control when braking.
Having ABS on only one axle still gives you more control over the vehicle while braking. The handbook says that ABS on only the tractor, only the trailer, or even only one axle still gives you more control during braking. It explains that ABS helps prevent wheel lockup, and locked wheels can cost you steering control or cause a skid or jackknife. It also says ABS may or may not shorten stopping distance, so the point is control, not faster stopping. For that reason, partial ABS is described as useful, and you should brake normally rather than treating it as dangerous.
8. What should happen before the air pressure in an air brake system tank falls below 55 psi?
- The warning light should activate. ✓
- The vehicle will be unable to shift out of gear.
- The front lights should flash.
Answer: A. The warning light should activate.
Before air tank pressure drops below 55 psi, the low air pressure warning light should come on. The handbook says vehicles with air brakes must have a visible low air pressure warning signal, and it must activate before tank pressure falls under 55 psi. It describes the warning as usually a red light, with a buzzer possible. The same rule appears when testing the warning signal: it must come on before pressure drops below that level. So the expected event is the warning light activating, not a gear or lighting change.
9. When inspecting the windshield before a trip, a person should do all the following, except:
- Remove and sharpen the wiper blades. ✓
- Check the windshield wipers for proper spring tension.
- Check the wiper blades for damage.
Answer: A. Remove and sharpen the wiper blades.
The action you should not do is remove and sharpen the wiper blades; a pre-trip inspection calls for checking the wipers, not altering them. The handbook's vehicle inspection section tells you to look at the wiper arms and blades, make sure they are secure and free of damage, and turn the wipers on to see that they work smoothly. It also says the blades should press firmly enough to clean the glass, and that washers should work. Nothing in those inspection steps says to take the blades off or sharpen them. Sharpening is not a wiper maintenance item listed for the pre-trip check.
10. When parked on a flat surface, you should:
- Use wheel chocks to prevent your vehicle from moving. ✓
- Not use wheel chocks.
- Use wheel chocks, but only if you have applied the parking brake.
Answer: A. Use wheel chocks to prevent your vehicle from moving.
When parked on a flat surface, use wheel chocks to prevent your vehicle from moving. The handbook says on a level surface you should place wheel chocks to hold the vehicle. A flat parking area is that kind of level surface, so chocks are the right step to keep the vehicle from rolling. The combination-vehicle section also treats chocks as a way to keep a trailer from moving, and the hazardous-materials section says to chock trailers and semi-trailers to prevent motion when they are uncoupled. Nothing in the passages makes chocking depend on first applying the parking brake.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook