Vehicle Equipment & Safe Operation — Idaho
Idaho CDL practice test: 416 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: 170 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 | Idaho CDL permit (CLP) knowledge tests |
| Topic questions | 170 (41% of 416 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 (170)
1. What helps prevent wheel lockup when braking?
- An Anti-Lock Braking System (ABS) ✓
- Air brakes
- An alternator
Answer: A. An Anti-Lock Braking System (ABS)
An Anti-Lock Braking System (ABS) helps prevent wheel lockup when braking. The handbook explains that sensors in the system detect a wheel that is about to lock up, and the electronic control unit then lowers brake pressure to that wheel so it keeps rolling instead of skidding. It adjusts pressure to give the most braking you can get without lockup, and it reacts faster than you could. The handbook also notes ABS may not shorten your stopping distance, but it keeps you in control during hard braking.
2. Dual tires should:
- Always come into contact with one another.
- Come into contact with one another fairly regularly.
- Not come into contact with one another. ✓
Answer: C. Not come into contact with one another.
Dual tires should not come into contact with one another. The handbook's tire inspection list names "dual tires that come in contact with each other or parts of the vehicle" as a problem to look for. Since the list describes conditions that make tires unsafe, touching is treated as a defect, not something normal, occasional, or harmless. Checking the tires by getting out and looking at them is also how you catch a dual tire problem, because a failing dual may not change how the vehicle feels.
3. Dual tires should:
- Not both be in contact with the road surface.
- Not touch one another. ✓
- Be different sizes from one another.
Answer: B. Not touch one another.
Dual tires should not touch one another. The handbook lists duals that touch as one cause of truck fires. That means the paired tires need clearance between them rather than rubbing against each other. The tire-check passage also tells you to get out and inspect all tires after stopping, including duals, because a failed dual may not be obvious from the driver's seat. Neither passage gives a reason to keep a dual off the road or to mix sizes; the fire-cause list is what supports keeping the two tires separated.
4. When inspecting your vehicle, you should check for all of the following, except:
- Too much air pressure in your tires.
- Too little air pressure in your tires.
- A consistent name brand across all of your tires. ✓
Answer: C. A consistent name brand across all of your tires.
You do not need to check for a consistent name brand across all of your tires. The handbook's tire checks focus on condition and air pressure, not on whether every tire carries the same brand name. It says to check tire mounting and air pressure, and it warns that pressure rises with heat, so you should not release air or pressure may be too low once tires cool. It also says a tire pressure gauge is the only acceptable way to check tire pressure. Nothing in these passages makes brand consistency an inspection item.
5. Which of the following is not part of a vehicle’s air brake system?
- Air gauges
- Low pressure warning device
- Air filter ✓
Answer: C. Air filter
An air filter is not part of a vehicle's air brake system. The handbook's air brake section describes the compressor, storage tanks, and the safety devices checked during inspection. In that inspection procedure, the air gauge is checked to confirm it is working and to watch pressure drop, and the low air warning devices (buzzer, light, and flag) are checked to confirm they activate before pressure falls below 55 psi. Both are treated as parts of the air brake system itself. An air filter is not listed among the air brake parts or among the devices inspected, so it does not belong to that system.
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. To determine if a vehicle can handle a load, you should:
- Know the vehicle’s suspension rating. ✓
- Know the tire rating for the front tires only.
- Start driving and see if the vehicle is handling well.
Answer: A. Know the vehicle’s suspension rating.
You should know the vehicle’s suspension rating. The handbook lists suspension systems as one of the weight ratings you need to know when checking weight and balance. It says suspension systems have a manufacturer’s weight capacity rating, so knowing that rating tells you whether the suspension is rated for the load. The same section also lists tire load and coupling device capacity, but the suspension rating is the listed vehicle rating that fits the idea of whether the vehicle can handle the load.
8. A low air pressure warning signal should activate:
- When tank pressure falls below 120 psi.
- When tank pressure falls below 60 psi. ✓
- When tank pressure falls below 10 psi.
Answer: B. When tank pressure falls below 60 psi.
The low air pressure warning signal should activate when tank pressure falls below 60 psi. The handbook says the warning must come on before the air pressure in the tanks drops below 55 psi, so you get a warning while there is still enough air to stop safely. Of the pressures listed, 60 psi is the only one above that 55 psi line. A signal set at 60 psi has already come on by the time pressure is near 55 psi, which is what the rule requires. The handbook also warns that a signal that does not work means you could lose air pressure without knowing it.
9. If unsure if a trailer has an Anti-Lock Braking System (ABS), you can:
- Look under the trailer for wheel speed sensors coming from the back of the brakes. ✓
- Remove a tire and look for the ABS sensor on the axle.
- Assume it does have ABS.
Answer: A. Look under the trailer for wheel speed sensors coming from the back of the brakes.
If you are unsure whether a trailer has ABS, look under the trailer for wheel speed sensor wires coming from the back of the brakes. The handbook says that on towed units built before ABS was required, it can be hard to tell whether the unit has ABS. It gives a specific check: look under the vehicle for the ECU and wheel speed sensor wires that come from the back of the brakes. That visual check is the stated way to identify ABS on an older trailer when the equipment is not obvious.
10. ABS allows a driver to:
- Drive faster.
- Maintain control of their vehicle while braking. ✓
- See farther ahead of their vehicle.
Answer: B. Maintain control of their vehicle while braking.
ABS allows a driver to maintain control of the vehicle while braking. The handbook explains that hard braking without ABS can lock the wheels. If the steering wheels lock, you lose steering control; if other wheels lock, the vehicle may skid, jackknife, or spin. ABS helps prevent wheel lockup and lets you keep control. It also says you may or may not stop faster with ABS, but you should be able to steer around an obstacle while braking and avoid skids from over braking.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook