General Driving Knowledge — Iowa
Iowa CDL practice test: 408 free practice questions (Based on the official driver handbook). The official format is not yet verified; check the official site before your test. General Driving Knowledge: 135 questions.
Questions that do not fit a single topic: lane use, turning, signalling and other rules of the road.
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 | General Driving Knowledge |
| License test | Iowa CDL permit (CLP) knowledge tests |
| Topic questions | 135 (33% of 408 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. When you are about to start down a hill, you should switch into a ____ gear.
- Higher
- Faster
- Lower ✓
Answer: C. Lower
You should switch into a lower gear before you start down a hill. The handbook says to slow down and shift down before beginning a descent so you can control speed without braking hard. It warns that relying too much on the brakes can overheat them and cause loss of braking power. It also says to pick a low enough gear, usually lower than the one you needed to climb that same hill. The engine's braking effect is strongest in lower gears, so choosing that gear before the grade helps you keep control.
2. Air storage tanks:
- Are not allowed on a vehicle.
- Hold compressed air for the brakes. ✓
- Should be drained of excess air after every trip.
Answer: B. Hold compressed air for the brakes.
Air storage tanks hold compressed air for the brakes. The handbook says air storage tanks are used to hold compressed air, and that they carry enough air for several brake applications even if the compressor stops working. So the tanks are the supply the brakes draw from. Nothing in the passages says tanks are banned, and the draining described is about removing water and oil, not air.
3. A manifest for transporting hazardous waste:
- Must be signed by hand. ✓
- Must be sent electronically.
- Must be attached to the outside of the trailer.
Answer: A. Must be signed by hand.
A hazardous waste manifest must be signed by hand. The handbook's hazardous waste section says that when you haul hazardous waste you must sign the manifest by hand and carry the Uniform Hazardous Waste Manifest. Shippers also prepare, date, and sign it by hand, and every carrier moving the shipment signs it by hand too. After delivery you keep your copy, and every copy needs the required signatures and dates, including the signature of the person who took the waste. Nothing in the passage describes an electronic substitute, so the hand signature is what the rule requires.
4. A Class 1 hazardous material is:
- An explosive. ✓
- Liquid.
- Corrosive.
Answer: A. An explosive.
A Class 1 hazardous material is an explosive. The handbook groups hazardous materials into nine hazard classes and lists explosion-related materials such as dynamite, blasting agents, and explosive devices among them. In its explosives section, it refers to Division 1.1, 1.2, and 1.3, which are divisions of the explosive class. That is why the Class 1 material in the question is an explosive. Liquids and corrosives describe other kinds of hazards, not the explosive class.
5. What does a shipping paper describe?
- The materials being transported ✓
- How the materials will be transported
- Who should accept the materials being transported
Answer: A. The materials being transported
A shipping paper describes the materials being transported—specifically, the hazardous materials in the load. The handbook says a shipping paper describes the hazardous materials being carried. It also lists shipping orders, bills of lading, and manifests as examples of shipping papers. That is why the correct choice is the one about the materials, not about transport arrangements or who receives them. The passage adds that after an accident or spill, responders can act better if they know which hazardous materials are involved, so the paper's job is to identify the cargo.
6. To prevent becoming an aggressive driver you should:
- Increase your speed.
- Make gestures at other drivers.
- Give other drivers the benefit of the doubt. ✓
Answer: C. Give other drivers the benefit of the doubt.
To prevent becoming an aggressive driver, give other drivers the benefit of the doubt. The handbook's section on not being an aggressive driver tells you to give other drivers the benefit of the doubt and try to imagine why they are driving that way. It points out that whatever their reason, it has nothing to do with you. The same page pairs this with slowing down, keeping a reasonable following distance, and being a cautious and courteous driver who says "Be my guest" when another driver wants to get in front. Accepting the delay and staying courteous is what keeps a stressful moment from turning into pushy, selfish driving.
7. When trying to put out an electrical fire, you should:
- Use water.
- Use a B:C extinguisher. ✓
- Use an X extinguisher.
Answer: B. Use a B:C extinguisher.
8. In a double or triple combination, the ____ trailer should be directly behind the cab.
- Lightest
- Heaviest ✓
- Smallest
Answer: B. Heaviest
9. When a vehicle goes around a corner, the rear wheels:
- Follow the same path as the front wheels.
- Follow a different path than the front wheels. ✓
- Should not be a concern to the driver.
Answer: B. Follow a different path than the front wheels.
They take a different path from the front wheels. The handbook calls this off-tracking, or cheating. It says the rear wheels do not trace the same line as the front wheels. Longer vehicles off-track more, and a trailer's rear wheels off-track more than the powered unit's. That is why you steer the front wide enough that the rear does not run over the curb or pedestrians, while keeping the rear close to the curb so other drivers cannot pass on the right.
10. You should ____ if the low pressure warning signal activates while you are driving.
- Stop where you are and park
- Exit the roadway as soon as safely possible ✓
- Continue driving normally
Answer: B. Exit the roadway as soon as safely possible
Exit the roadway as soon as safely possible when the low pressure warning signal activates while driving. The handbook says that when the low air pressure warning comes on, you should stop and safely park as soon as possible because there may be an air leak. It also explains that you can control braking only while enough air remains in the tanks. The spring brakes will apply when pressure drops into the 20 to 45 psi range, and a lightly loaded vehicle or one on slippery roads may skid when that happens. Getting safely off the roadway while the foot brakes still work is therefore the safer action.
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Last checked: 2026-10-17 · Not yet verified
Updated: · Based on the official driver handbook