Louisiana CDL — General Knowledge Practice Test
The Louisiana CDL — General Knowledge knowledge test has 50 questions, and you need 40 correct (80%) to pass. Practice free with questions written from the official Louisiana driver handbook — every one has a clear explanation, and you can retake as often as you like with no sign-up.
Content reviewed against official driver handbooks · July 7, 2026
What's on the Louisiana written test
The Louisiana CDL — General Knowledge knowledge test has 50 questions; you need 40 correct (80%) to pass.
Based on the official Louisiana exam format — always confirm current details with your state DMV.
Practice by topic
Focus on one area at a time — each topic has its own set of Louisiana practice questions.
Learn the shapes, colors, and meanings of regulatory, warning, and guide signs — from stop and yield to construction and school-zone signs.
Speed limits, turning and signaling rules, headlight and seat-belt requirements, and the everyday laws every driver must follow.
How to read traffic signals, lane lines, and pavement markings — including yellow and white lines, arrows, and flashing lights.
Who goes first at intersections, four-way stops, roundabouts, and crosswalks, and how to yield to pedestrians and emergency vehicles.
Following distance, scanning, blind spots, using your lights, and the habits that prevent crashes and keep you in control.
Driving safely around motorcycles, bicycles, large trucks, pedestrians, and school buses — and knowing who has the right of way.
Blood alcohol limits, zero-tolerance and implied-consent laws, and how alcohol and drugs — legal or not — affect your driving.
Legal and illegal parking, colored curbs, distances from hydrants and crossings, and how to park safely on hills.
Choosing a safe speed, keeping a space cushion, adjusting for weather and traffic, and understanding stopping distance.
What to do when things go wrong — brake failure, tire blowouts, skids, and stalling on railroad tracks.
The point system, license suspension, provisional-license rules, insurance requirements, and other licensing basics.
How to pass the first time
- Read the official Louisiana driver handbook at least once before test day.
- Practice by topic to find your weak spots, then fix them.
- Take full-length practice tests until you pass comfortably every time.
- Read every explanation — understanding beats memorizing.
Louisiana CDL — General Knowledge test — frequently asked questions
How many questions are on the Louisiana CDL — General Knowledge test?
The Louisiana CDL — General Knowledge knowledge test has 50 questions, and you need 40 correct (80%) to pass. Our practice tests mirror that format.
How many questions can I miss on the Louisiana CDL — General Knowledge test?
You can miss up to 10 of the 50 questions and still pass — you need 40 correct, which is 80%.
Can I retake the practice test?
Yes — practice as often as you like, completely free. The questions and answer choices are shuffled each time.
Can I take the Louisiana practice test in Spanish?
Yes. Every question here is available in English and Spanish — switch languages anytime. Many states also offer the real knowledge test in languages other than English; confirm what Louisiana offers with your DMV.
Can I practice on my phone?
Yes. The practice tests work in any mobile or desktop browser — no app or sign-up needed — so you can study anywhere.
Are these the real DMV test questions?
No. Our questions are original, written from the current official Louisiana driver handbook to match the real test's topics and style. We are not affiliated with any DMV or government agency.
What's the best way to study?
Read the Louisiana driver handbook, practice by topic to target weak areas, and finish with full-length tests until you consistently pass.
Other Louisiana practice tests
Take the CDL — General Knowledge test in another state
Every Louisiana question is written from the official Louisiana driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free
Louisiana CDL — General Knowledge questions with answers
20 sample questions from the Louisiana CDL — General Knowledge question bank — each with the correct answer, a short explanation, and the section of the official handbook it comes from.
1. Which knowledge test must every CDL applicant take?
Correct answer: The general knowledge test
All CDL applicants must pass the general knowledge test.
Source: Louisiana CDL Manual, Section 1.1.1 (Knowledge Tests)
2. Compared with a loaded truck, how does an empty truck stop?
Correct answer: It needs a greater distance because it has less traction
An empty truck has less traction, so it actually needs a greater distance to stop than a fully loaded one.
Source: Louisiana CDL Manual, Section 2.6.1 (The Effect of Vehicle Weight on Stopping Distance)
3. Your hydraulic brake pedal goes to the floor. Which of these can help slow the vehicle?
Correct answer: Downshifting and using the parking brake
You can downshift, pump the pedal to build pressure, and use the parking brake to slow a vehicle that has lost hydraulic braking.
Source: Louisiana CDL Manual, Section 2.17.3 (Brake Failure)
4. You are in the right lane and a truck is trying to merge onto the highway from an on-ramp. What is the courteous and safe action?
Correct answer: Move over to let the truck merge
Courtesy says move over to give the merging truck room, since a big rig needs much more time to reach highway speed.
Source: Louisiana CDL Manual, Sharing the Road with Big Trucks
5. About how much alcohol can the liver process in one hour?
Correct answer: About one drink per hour
The liver can only clear roughly one drink's worth of alcohol per hour, so drinking faster than that builds up your BAC.
Source: Louisiana CDL Manual, Section 2.22.1 (Alcohol and Driving)
6. Because a motorcycle presents such a small profile, how may it appear to other drivers?
Correct answer: Farther away and slower than it really is
A motorcycle's narrow silhouette can make it look farther away and slower than it actually is, so take a second look.
Source: Louisiana CDL Manual, Sharing the Road with Motorcycles
7. A crossbuck sign at a railroad crossing requires a driver to do what?
Correct answer: Yield the right-of-way to an approaching train
The X-shaped crossbuck marks the crossing and means you must give the right-of-way to any approaching train.
Source: Louisiana CDL Manual, Section 2.15.2 (Warning Signs and Devices)
8. During the engine-compartment step of a pre-trip inspection, what must be done before you raise the hood or tilt the cab?
Correct answer: Confirm the parking brake is set or the wheels are chocked
Make sure the parking brakes are on and/or the wheels are chocked before you open or tilt the engine compartment.
Source: Louisiana CDL Manual, Section 2.1.5 (Seven-step Inspection Method)
9. Within how many feet of an oncoming vehicle must you dim your high-beam headlights at night?
Correct answer: 500 feet
You should switch from high to low beam within 500 feet of an approaching vehicle to avoid blinding that driver.
Source: Louisiana CDL Manual, Section 2.11.5 (Night Driving Procedures)
10. About how much steering wheel play begins to make a vehicle hard to steer?
Correct answer: More than about 10 degrees of play
More than about 10 degrees of play, roughly 2 inches at the outer edge of a 20-inch wheel, makes a vehicle hard to steer.
Source: Louisiana CDL Manual, Section 2.1.3 (Steering System Defects)
11. How many driver licenses is a commercial driver permitted to hold at one time?
Correct answer: Only one license
A commercial driver may hold only one license; breaking this rule can bring a fine and jail time.
Source: Louisiana CDL Manual, Section 1.4 (Other CDL Rules)
12. Which endorsement is required to drive a tank vehicle?
Correct answer: The N endorsement
The 'N' endorsement is required to operate a tank vehicle carrying liquid or gas in large quantities.
Source: Louisiana CDL Manual, Section 1.1 (CDL Endorsements)
13. On packed snow, how much should you reduce your speed?
Correct answer: By about half or more
On packed snow you should cut your speed by half or more to keep traction.
Source: Louisiana CDL Manual, Section 2.6.2 (Matching Speed to the Road Surface)
14. When you do not have enough room to stop for an obstacle, what is often the better choice?
Correct answer: Steer around the obstacle
You can usually steer around an obstacle faster than you can stop, so turning away may be the better option.
Source: Louisiana CDL Manual, Section 2.17.1 (Steering to Avoid a Crash)
15. Before you start across a road with a large, slow vehicle, what must you be sure of?
Correct answer: That you can clear the whole roadway before approaching traffic arrives
Make sure you can clear the entire road before approaching traffic reaches you, because big vehicles accelerate slowly.
Source: Louisiana CDL Manual, Section 2.7.7 (Space Needed to Cross or Enter Traffic)
16. What effect can other drugs have when combined with alcohol?
Correct answer: Alcohol can worsen the effects of other drugs considerably
Combining alcohol with other drugs can worsen their effects considerably, so the safest rule is never to mix any drug with driving.
Source: Louisiana CDL Manual, Section 2.22.2 (Other Drugs)
17. How much of a traffic lane is a motorcycle entitled to use?
Correct answer: The full width of the lane
A motorcycle is allowed the full width of a lane; do not try to share the lane with one.
Source: Louisiana CDL Manual, Sharing the Road with Motorcycles
18. A small sign mounted just below a crossbuck at a rail crossing tells you what?
Correct answer: The number of tracks at the crossing
When a crossing has more than one set of rails, a plate under the crossbuck states how many tracks there are.
Source: Louisiana CDL Manual, Section 2.15.2 (Warning Signs and Devices)
19. You are stopped just beyond a hill or curve that blocks the view of your vehicle. What should you do with the rear warning triangle?
Correct answer: Move it back so drivers are warned within 500 feet
Move the back triangle farther down the road, back beyond the hill or curve, so approaching drivers get warning within 500 feet.
Source: Louisiana CDL Manual, Section 2.5.2 (Communicating Your Presence)
20. In rain, fog, or at dawn and dusk, which lights should you switch on to be seen?
Correct answer: Your low-beam headlights
When it is hard to see, turn on your headlights using the low beams rather than only clearance or identification lights.
Source: Louisiana CDL Manual, Section 2.5.2 (Communicating Your Presence)