CDL practice test 2026: all three Class A permit tests, free

This free CDL-style practice test has 95 original questions in the three knowledge tests a Class A permit needs: 50 General Knowledge, 25 Air Brakes and 20 Combination Vehicles, each on a practice clock of about a minute a question. You get a score for each test against the 80% you need to pass it, because the DMV scores each one separately.

95
questions, three tests: 80%
needed on each real test: 40 / 20 / 16
correct answers to pass: Free
no sign-up

Last checked 20 October 2026 · Test facts from 49 CFR 383 and the Washington State Department of Licensing

95
questions
95 min
time limit
Free
instant score

3 timed parts, each on its own clock: General Knowledge, 50 questions in 50 minutes, then Air Brakes, 25 questions in 25 minutes, then Combination Vehicles, 20 questions in 20 minutes. A part's clock starts when you begin it, and you cannot go back to an earlier part.

By the LifeScore Editorial Team · Updated 20 October 2026 · How we check facts · How this is scored

What is on this CDL practice test?

Ninety-five original questions written from the federal rules and the standard state CDL manual, in three parts sized like the real tests: General Knowledge (50), Air Brakes (25) and Combination Vehicles (20).

General Knowledge covers what every commercial driver must know: the seven-step inspection, shifting, seeing and communicating, space and speed, night and winter driving, hazards, emergencies, skids, crashes, fires, alcohol and fatigue, and cargo. Air Brakes covers the parts of the system, the air brake check and how to brake on the road. Combination Vehicles covers rollovers, trailer air brakes and coupling and uncoupling.

Most questions test a rule you can learn once. About one in seven uses a rule with numbers: following distance from your vehicle's length, a leakage limit in psi, the tread depth on a steering tire. Those are the questions people lose by half-remembering, so we change the numbers in every mock and make you apply the rule rather than recognize an answer.

What this practice test copies, and what it does not
Parts	General Knowledge, Air Brakes and Combination Vehicles, in that order
Questions	50, 25 and 20: 95 in all, four options each, mixed easy and hard within each part
Clock	A practice pace of about a minute a question: 50, 25 and 20 minutes
Your result	Percent right for each part against the 80% line, and a practice band. Not a pass or a permit
Questions with numbers	About one in seven uses a rule with numbers (psi limits, following distance, tread depth), with the numbers changing every mock

Can I practise just General Knowledge, Air Brakes or Combination?

Yes. Each test has its own page with a free 12-question drill, every answer explained from the manual, and the rules and numbers that test asks about most.

CDL General Knowledge test
1 free drill
Inspection, basic control, shifting, seeing, communicating, space and speed management, night and winter driving, hazards, emergencies, skids, crashes, fires, alcohol and fatigue, cargo.
CDL Air Brakes test
1 free drill
The parts of an air brake system, dual systems, the air brake check, using air brakes, spring brakes, ABS, brake fade.
CDL Combination Vehicles test
1 free drill
Driving combinations safely, rollover and rearward amplification, trailer air brakes, coupling and uncoupling, inspecting a combination.

Take the full test first, then drill the part with the lowest score. Because the DMV scores each knowledge test on its own, a strong General Knowledge score does not rescue a weak Air Brakes score: you would leave with an air brake restriction or have to come back for that test.

How do the real CDL knowledge tests work?

Your state gives them at the licensing office, usually on a computer: separate multiple-choice tests for General Knowledge, Air Brakes and Combination Vehicles, each needing 80% to pass, and passing them gets you a commercial learner's permit.

The real tests, with where each fact comes from
Who gives them	Your state licensing agency (DMV, DOL or BMV), under federal rules in 49 CFR 383Published by the ownerFMCSA, "Commercial Driver's License"
Tests for a Class A permit	General Knowledge, Air Brakes and Combination Vehicles, plus any endorsement tests you wantPublished by the ownerWashington State Department of Licensing, "CDL knowledge test"
Questions	General Knowledge 50, Air Brakes 25, Combination Vehicles 20 in Washington; some states ask 20 Air Brakes or 25 Combination questionsPublished by the ownerWashington State Department of Licensing, "CDL knowledge test"
Pass mark	At least 80% on each test, scored separatelyPublished by the ownereCFR, 49 CFR 383.135, passing knowledge and skills tests
Format	Multiple choice, usually on a computer at the licensing officePublished by the ownerWashington State Department of Licensing, "CDL knowledge test"
Time limit	Set by each state; many do not time each test tightly, but check your state's rulesSourcedWashington State Department of Licensing, "CDL knowledge test"
What you get	A commercial learner's permit (CLP), which you must hold for 14 days before the skills testPublished by the ownereCFR, 49 CFR 383.25, commercial learner's permit

The three Class A permit tests, Washington's published counts
Test	Questions	Correct to pass	Who takes it
General Knowledge	50	40 (80%)	Everyone, for every class
Air Brakes	25	20 (80%)	Anyone driving a CMV with air brakes (or you get an air brake restriction)
Combination Vehicles	20	16 (80%)	Class A applicants

The questions are drawn from your state's CDL manual, and every state's manual follows the same national model, so the rules are almost identical from state to state. What differs is the paperwork: fees, how many times you can retest in a day, and whether you book an appointment. Read the CDL test guide for the full path from permit to license.

What numbers do I need to memorize for the CDL test?

A short list of rules with numbers decides more knowledge-test questions than anything else: following distance, stopping distance, tread depth, warning triangles, cargo checks, the alcohol rules and the air brake pressures and limits.

The numbers the knowledge tests ask about most, with where each comes from
Rule	Number	Source
Following distance	1 second per 10 feet of vehicle length below 40 mph; add 1 second above 40 mph	State CDL manual
Stopping at 55 mph (dry)	About 142 ft perception + 61 ft reaction + 216 ft braking = 419 ft; air brakes add about 32 ft of lag	State CDL manual
Tread depth	At least 4/32 inch on front (steering) tires, 2/32 inch on all others	49 CFR 393.75
Warning triangles, two-way road	Within 10 ft of the vehicle, then about 100 ft behind and 100 ft ahead	State CDL manual
Warning triangles, divided or one-way road	10 ft, 100 ft and 200 ft behind, toward approaching traffic	State CDL manual
Cargo checks	Within the first 50 miles, then every 3 hours or 150 miles, whichever comes first	State CDL manual
Alcohol	None within 4 hours of duty; 0.04 is DUI in a CMV; any detectable amount means 24 hours out of service	49 CFR 392.5; state CDL manual
Governor	Cut-out about 125 psi, cut-in about 100 psi	State CDL manual, air brakes
Low-air warning	Must come on before pressure falls below 60 psi	State CDL manual, air brakes
Spring brakes / tractor protection valve	Come on, or close, between 20 and 45 psi	State CDL manual, air brakes and combinations
Air build-up (dual system)	85 to 100 psi within 45 seconds	State CDL manual, air brakes
Leakage, engine off	Released: under 2 psi a minute (single), 3 (combination). Applied: under 3 (single), 4 (combination)	State CDL manual, air brakes
Slack adjuster free play	No more than about 1 inch when pulled by hand	State CDL manual, air brakes

Learn them in pairs that look alike and differ: 4/32 and 2/32 inch, 20 to 45 psi and 60 psi, 2 and 3 psi released, 3 and 4 psi applied. Most wrong answers on these questions are the right number from the neighboring rule.

What do CDL test questions look like?

Short questions with four options, some about a rule and some about a situation on the road. Try the six below: two are worked step by step and the rest open when you tap.

CDL-style question 1 · Following distance
You are driving a 70-foot combination at 50 mph on a dry road. By the CDL manual's rule, at least how many seconds should you leave between you and the vehicle ahead?
1. A7 seconds
2. B8 seconds
3. C5 seconds
4. D10 seconds
Worked answer
B: 8 seconds. One second for each 10 feet of length is 7 seconds, and you add 1 second because you are above 40 mph: 8 seconds.
1. Length: 70 ÷ 10 = 7 seconds.
2. Speed is over 40 mph, so add 1 second.
3. 7 + 1 = 8 seconds.
The trap: Stopping at 7. The extra second above 40 mph is the part of the rule people forget.
CDL-style question 2 · Hazards
You stop on the shoulder of a two-lane road with traffic both ways. Where should your three warning triangles go?
1. AAll three behind you, 10, 100 and 200 feet back
2. BOne within 10 feet of the vehicle on the traffic side, one about 100 feet behind and one about 100 feet ahead
3. COne beside each front tire and one at the rear
4. DOne 500 feet behind you and two at the vehicle
Show the worked answer
B: One within 10 feet of the vehicle on the traffic side, one about 100 feet behind and one about 100 feet ahead. On a two-way road, traffic can come from either side, so you protect both directions: one by the vehicle, one about 100 feet behind and one about 100 feet ahead.
1. Ask which way traffic comes from: both ways on a two-lane road.
2. So you need a triangle ahead as well as behind.
3. Pattern: within 10 feet, then about 100 feet in each direction.
The trap: The 10-100-200 pattern is for one-way or divided roads, where all traffic comes from behind.
CDL-style question 3 · Air brake check
With the engine off and the brakes released, a single truck's air pressure drops 3 psi in one minute. Does it pass the static leakage test?
1. AYes; the limit is 4 psi a minute
2. BNo; the limit is less than 2 psi a minute
3. CYes; the limit is less than 3 psi a minute
4. DNo; there should be no drop at all
Worked answer
B: No; the limit is less than 2 psi a minute. Released (static) leakage must be less than 2 psi a minute for a single vehicle and less than 3 for a combination. 3 psi fails on a single truck.
1. Released or applied? Released (brakes off).
2. Single or combination? Single.
3. Limit: less than 2 psi a minute. 3 psi fails.
The trap: Using the combination or applied limit. Four numbers (2, 3, 3, 4) look alike; tie each to its condition.
CDL-style question 4 · Low air
You test the low air pressure warning by fanning the brakes with the engine off. It comes on at 50 psi. What does that mean?
1. AIt is working correctly
2. BIt comes on too late; it must come on before pressure falls below 60 psi
3. CIt comes on too early; it should come on at 20 psi
4. DThe governor is set too high
Show the worked answer
B: It comes on too late; it must come on before pressure falls below 60 psi. The low-air warning must activate before tank pressure falls below 60 psi. At 50 psi it is late, so it needs repair before driving.
1. Recall the rule: the warning must come on before 60 psi.
2. 50 psi is below 60.
3. So the warning is late: have it fixed.
The trap: Confusing the warning with the spring brakes (20 to 45 psi). The warning has to come well before the brakes do.
CDL-style question 5 · Air system
What happens when you pull out the red, eight-sided trailer air supply knob?
1. AThe trailer brakes release
2. BThe air to the trailer is shut off and the trailer emergency brakes come on
3. CThe fifth wheel unlocks
4. DThe tractor parking brakes release
Show the worked answer
B: The air to the trailer is shut off and the trailer emergency brakes come on. Pulling the red knob closes the tractor protection valve, cutting air to the trailer, so the trailer's spring (emergency) brakes apply.
1. Red, eight-sided knob = trailer air supply.
2. Pulled out = supply off.
3. No supply air = trailer emergency brakes on.
The trap: Mixing it up with the yellow diamond knob, which controls the parking brakes on the tractor (and trailer, when supplied).
CDL-style question 6 · Doubles
You are coupling doubles. Trailer 1 is loaded to 22,000 lb and trailer 2 to 14,000 lb. Which goes directly behind the tractor?
1. ATrailer 2, because the lighter trailer goes first
2. BTrailer 1, because the heavier trailer goes first
3. CEither; the order does not matter
4. DTrailer 2, so the heavy one is at the back for traction
Show the worked answer
B: Trailer 1, because the heavier trailer goes first. The heavier trailer goes first, behind the tractor, and the lighter one at the rear, which keeps the rear trailer from pushing and whipping.
1. Compare the weights: 22,000 lb is heavier.
2. Rule: heaviest trailer first.
3. Trailer 1 goes behind the tractor.
The trap: Thinking the heavy trailer belongs at the back "for stability". A heavy rear trailer amplifies swing in a quick lane change.

These were written for this page, so none of them is in a mock. More, each with its trap, are on CDL sample questions.

After the free CDL-style test

One mock shows which test is below 80%. Seven more, and four drills for each test, prove it is fixed.

The CDL Pass Pack gives you 8 full mocks on the real clock, 12 drills of 12 questions for the sections that cost you points, and a predictor that turns your mocks into the odds of reaching your target. One payment, no subscription, and your free score stays free.

Prep courses for these tests usually cost $19 to $129. The CDL Pass Pack is US$39 (£29), once.

See the CDL Pass Pack How our questions are built and checked

8
timed mocks: 12
topic drills: 1
score predictor

How do I read my CDL practice result?

You get the percent you got right on each of the three tests, compared with the 80% line, and a practice band for the whole test: Early practice, Building (60%+), Close (70%+), At the line (80%+) or Strong (90%+). These are our labels, not a DMV result.

Read each test on its own. If General Knowledge is at 86% but Air Brakes is at 72%, you are not ready, because Air Brakes is its own test with its own 80% line. Your result page names the part furthest below 80% and starts your study plan there.

A practice score is a measure of how well you know the manual on our questions, not a prediction. The safest sign you are ready is clearing 80% on every part in two different mocks, on questions you have not seen before.

Do CDL practice tests help you pass?

Yes, if you use them to find the rules you do not know and then read those sections of the manual; memorizing practice answers does not work, because the real questions are worded differently.

The CDL manual is long, and most people read it front to back once and walk into the DMV hoping. A practice test turns that around: it shows you which ten pages you actually need to reread. Each wrong answer here comes with the rule behind it, so a miss is a pointer to a section, not just a red mark.

Failing costs more than time. Most states charge to retest, many make you wait before trying again, and your training school or employer may be waiting on your permit to start your behind-the-wheel training. The step-by-step plan is in how to pass the CDL test, and the 80% rule is explained on CDL passing score.

Frequently asked questions

Is this the real CDL test?

No. It is a CDL-style practice test with original questions written from the federal rules and the standard state CDL manual. The real tests are given by your state licensing agency.

How many questions are on the CDL permit test?

For a Class A permit, Washington lists 50 General Knowledge, 25 Air Brakes and 20 Combination questions. Some states ask 20 Air Brakes or 25 Combination questions. Endorsements add more tests.

What score do I need to pass?

At least 80% on each test: 40 of 50, 20 of 25 and 16 of 20 with Washington's counts. Each test is scored on its own.

Do I need the Air Brakes test?

If you want to drive a CMV with air brakes, yes. Without it, your CDL carries an air brake restriction. Most tractor-trailers have air brakes.

Do I need the Combination test for Class B?

No. Combination Vehicles is for Class A. A Class B permit usually needs General Knowledge and, for most trucks and buses, Air Brakes.

Is the CDL test the same in every state?

The rules come from the same national model manual, so the content is nearly the same. Counts, fees and retest rules vary, so check your state's page.

Do I have to pay?

The full practice test and the three section drills are free with no sign-up. The Pass Pack, with seven more mocks, 12 drills and every answer explained, is a one-time payment.

Walk into the DMV ready for all three

Eight full CDL-style mocks, four drills for each knowledge test and every answer explained from the manual, in one payment with no subscription.