General Driving Knowledge — District of Columbia
District of Columbia CDL practice test: 423 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: 157 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 | District of Columbia CDL permit (CLP) knowledge tests |
| Topic questions | 157 (37% of 423 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
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Questions (157)
1. Which of the following may result in an applicant being denied a hazardous materials endorsement?
- They are not a lawful permanent resident of the United States. ✓
- They have had a speeding conviction within the previous three years.
- They did not correctly answer every question on the written hazardous materials endorsement test.
- They did not pass the written hazardous materials endorsement test on the first attempt.
Answer: A. They are not a lawful permanent resident of the United States.
An applicant may be denied a hazardous materials endorsement if they are not a lawful permanent resident of the United States. The handbook says you will be denied or lose a hazardous materials endorsement if you are not a lawful permanent resident of the United States. It also lists other security-related grounds, such as renouncing citizenship, being wanted or under indictment for certain felonies, certain felony convictions, being adjudicated as lacking mental capacity, or being considered a security threat. The passage does not list a speeding conviction or written-test scoring as denial grounds for this endorsement.
2. In a combination rig, it is best to make:
- Quick, sudden stops.
- Sharp turns.
- Quick accelerations.
- Slow, planned stops. ✓
Answer: D. Slow, planned stops.
In a combination rig, it is best to make slow, planned stops. The combination vehicle section tells you to allow lots of following distance and look far down the road so you can brake early. It warns against being surprised into a panic stop. Planned, gradual braking fits that advice, and the same section says to steer gently and smoothly because sudden moves can tip a trailer. Other sections on mountain grades and fog also stress choosing a safe speed and slowing down before conditions force you.
3. When driving a bobtail tractor, you should be aware that:
- Bobtails stop very easily.
- Bobtails cannot drive as fast as tractors with semitrailers.
- Bobtails are more difficult to stop than tractors with semitrailers. ✓
- Bobtails are illegal in most states.
Answer: C. Bobtails are more difficult to stop than tractors with semitrailers.
A bobtail tractor is more difficult to stop than a tractor with a semitrailer. The handbook warns that bobtail tractors can be very hard to stop smoothly. Tests show a bobtail takes longer to stop than a tractor-semitrailer loaded to maximum gross weight. It also explains that light loads give poor traction, and stiff springs and strong brakes make wheel lockup easy. So the lack of a trailer does not make stopping easier; it makes the rig harder to control when braking.
4. Shippers must label hazardous materials. If an item is smaller than its label, how should the item be labeled?
- The item may be tied together with other hazardous materials and labeled with a sheet of paper on the outside of the bundle.
- The label may be attached to a tag that is securely attached to the package. ✓
- The item may be marked with a large orange dot.
- The item may be placed in a box displaying a warning label.
Answer: B. The label may be attached to a tag that is securely attached to the package.
5. What is a danger of rolling back when you start to accelerate?
- The transmission may be damaged.
- The truck is not made to go backwards.
- You may hit a vehicle behind you. ✓
- You may lose your position in traffic.
Answer: C. You may hit a vehicle behind you.
The danger is that you may hit a vehicle behind you, so you should not roll back when you start to accelerate. The handbook's starting instruction is simple: don't roll back. It explains that rolling back can cause you to hit someone behind you. For a manual transmission, it suggests partly engaging the clutch before you take your right foot off the brake, and it says to use the parking brake when needed to keep from rolling back. The answer matches that warning: the risk is a collision with whatever is behind you, not a mechanical problem or a traffic-position issue.
6. During an applied leakage test, the maximum leakage rate for a triple combination vehicle is:
- 10 psi in a minute.
- 8 psi in a minute.
- 6 psi in a minute. ✓
- 4 psi in a minute.
Answer: C. 6 psi in a minute.
7. Driving a combination vehicle ____ than driving a single vehicle.
- Is easier
- Requires more driving skill ✓
- Is better for training
- Is safer in inclement weather
Answer: B. Requires more driving skill
Driving a combination vehicle requires more driving skill than driving a single vehicle. The combination vehicles section says these vehicles are usually heavier and longer, and that they call for more driving skill than single commercial vehicles. It also says their drivers need more knowledge and skill. That matches the choice about requiring more driving skill; the handbook does not present combination driving as easier, a training advantage, or safer in bad weather.
8. How must a shipper notify a driver of the risks associated with their cargo?
- By speaking with the driver
- By writing a note on a blank piece of paper
- By putting hazard warning labels on packages ✓
- By placing orange dots on packages
Answer: C. By putting hazard warning labels on packages
The shipper must put hazard warning labels on packages to notify the driver of the cargo risks. The handbook says shippers have a duty to communicate a material's hazards to drivers and others. It lists hazard warning labels on packages as one required way to do that, along with shipping papers, emergency response information, and placards. Another passage describes the shipper using diamond-shaped hazard labels and a shipping paper to warn dockworkers and drivers. Among the choices, putting hazard warning labels on packages is the method the handbook names for warning the driver.
9. In a double or triple combination:
- Cargo weight must be evenly distributed between all trailers.
- The heaviest trailer should be positioned directly behind the cab. ✓
- The heaviest trailer should be positioned in the rear.
- The weight of the trailers does not matter.
Answer: B. The heaviest trailer should be positioned directly behind the cab.
10. If transporting explosives, you may leave your vehicle unattended:
- In a rest area.
- At a truck stop.
- On private property.
- In a safe haven. ✓
Answer: D. In a safe haven.
When you are hauling explosives, the only place you may leave your vehicle unattended is in a safe haven — an approved parking spot for unattended vehicles loaded with explosives. The handbook says you are allowed to leave your vehicle unattended in a safe haven, and it defines a safe haven as an approved place for parking unattended vehicles loaded with explosives. It also notes that local authorities usually decide which spots are designated as authorized safe havens. So the permission to park unattended and walk away depends on the spot being an approved one, not on it simply being a place where trucks commonly park.
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Last checked: 2026-10-17 · Verified from official source
Updated: · Based on the official driver handbook