MN · GK Endorsement

Minnesota General Knowledge CDL Practice Test

Below are 25 exam-style questions for the Minnesota General Knowledge CDL knowledge test, modeled on the FMCSA-aligned content used by the Minnesota Driver and Vehicle Services. Try to answer each question on your own before reading the answer key directly under it. The questions and answer choices are shuffled deterministically per state and endorsement, so the order will stay the same on repeat visits — that lets you genuinely measure your improvement.

Heads up: this is a study tool, not a graded exam. Cover the answer with your hand or a sheet of paper for an honest practice run, then re-read the explanations for any questions you missed. Aim for 22 out of 25 or better, three times in a row, before scheduling the real exam.

Question 1 of 25

When checking the engine compartment, you should make sure that:

A Engine oil level is safe to operate
B Coolant level is above LOW and the cap is secure
C All of the above
D Power steering fluid is at the proper level

Correct answer: C

A proper engine-compartment check covers oil, coolant, power steering fluid, windshield washer fluid, hoses, belts, and electrical wiring. Skipping any one of them defeats the purpose of the inspection.

Question 2 of 25

A controlled braking technique means:

A Pumping the brakes hard and fast
B Locking the wheels
C Applying the brakes as hard as possible without locking the wheels
D Coasting in neutral

Correct answer: C

Controlled braking applies brakes hard but stops short of wheel lock-up. With ABS, you can simply press and hold full pressure.

Question 3 of 25

Which is true about brake lining wear and adjustment?

A Brake adjustment is the dispatcher's responsibility
B Brakes self-adjust forever
C Slack adjusters need periodic checking; pushrod travel beyond limits is out-of-service
D Drum brakes never need adjustment

Correct answer: C

Slack adjusters can fail, and pushrod travel must be within limits. Drivers check; adjustment itself is a maintenance task for qualified personnel.

Question 4 of 25

Which is true about driving in mountains?

A All of the above
B Engine braking helps keep speed under control
C Brakes alone are not designed to hold a heavy vehicle on a long downgrade
D Heavy vehicles can slow down sharply on grades

Correct answer: A

Mountain driving combines all three. Use of low gears, engine braking, and short, moderate service-brake applications is the safe combination.

Question 5 of 25

When you are being tailgated, you should:

A Speed up to get away
B Increase your following distance from the vehicle in front to give both of you more room
C Brake suddenly to teach a lesson
D Move to the left lane only

Correct answer: B

Adding cushion ahead gives the tailgater room to pass safely and reduces the chance of a chain rear-end collision.

Question 6 of 25

Which is true about communicating in heavy traffic?

A Never communicate; just drive
B Honk loudly to warn other drivers
C Make eye contact only when stopped
D Tap the horn lightly or flash lights to signal your presence

Correct answer: D

A light tap of the horn or a brief headlight flash communicates your presence without startling others. A loud, prolonged horn can provoke aggressive responses.

Question 7 of 25

The proper response to a tire blowout on the front axle is to:

A Steer sharply toward the shoulder
B Hold the steering wheel firmly, ease off the accelerator, and let the vehicle slow down
C Brake immediately and pull off the road
D Shift to neutral and coast

Correct answer: B

Hard braking after a blowout can cause loss of control. Hold the wheel, release the accelerator, and let speed bleed off before braking gently.

Question 8 of 25

When the road is slippery, you should:

A All of the above
B Make smooth steering and braking inputs
C Increase following distance
D Slow down

Correct answer: A

Slippery roads require all three: more cushion, smoother inputs, and lower speed.

Question 9 of 25

Cargo that hangs more than 4 feet beyond the back of the vehicle must be marked with:

A Nothing — federal rules do not require marking
B A green flag
C A red flag (or red light at night) at the extreme rear
D Yellow tape only

Correct answer: C

Federal rules require a red flag during the day and red lights at night for projecting cargo beyond 4 feet.

Question 10 of 25

A vehicle's "no-zone" is:

A The area immediately next to it where other drivers are hidden in your blind spots
B The fuel tank area
C The area in front of the steer axle
D A federal speed restriction

Correct answer: A

No-zones are the four blind-spot areas (front, rear, and both sides) where smaller vehicles are difficult or impossible to see in your mirrors.

Question 11 of 25

A driver who refuses to take a required drug or alcohol test is treated as if they:

A Took the test and passed
B Took the test and failed
C Need to take it again later
D Did not take the test, with no consequence

Correct answer: B

Refusal is a federal CDL disqualification with the same consequences as a positive test.

Question 12 of 25

Black ice is most likely on:

A Roads in direct sunlight
B Concrete pavement only
C Gravel surfaces
D Bridges and overpasses

Correct answer: D

Bridges and overpasses freeze first because cold air circulates above and below them. They are the most-asked test scenario for sudden ice.

Question 13 of 25

A driver should test the parking brake by:

A Releasing the parking brake on a flat surface and tugging gently against it
B Setting the parking brake, releasing the service brakes, and gently trying to move the vehicle in low gear
C Driving over a speed bump
D Pumping the brakes

Correct answer: B

The standard test: set parking brakes, gently apply throttle in low gear; if the vehicle moves, the parking brake is not holding.

Question 14 of 25

Drivers may not drive after being on duty:

A 14 consecutive hours since coming on duty
B 20 hours in a 24-hour period
C 8 hours in any 24-hour period
D 15 hours of driving

Correct answer: A

The 14-hour rule limits the on-duty window during which up to 11 hours of driving may occur.

Question 15 of 25

When should you do an en-route inspection?

A Only when the load is hazardous
B Within the first 25 miles, then about every 150 miles or every 3 hours
C At the end of the trip
D Only if a warning light comes on

Correct answer: B

The FMCSA model manual recommends a check within the first 25 miles to catch loose cargo or under-inflated tires that have warmed up, then about every 150 miles or 3 hours, and any time you stop.

Question 16 of 25

Stab braking is used:

A On vehicles without ABS, to keep them straight in an emergency
B To save fuel
C On wet roads only
D On vehicles with ABS

Correct answer: A

Stab braking — full application then release as soon as wheels lock, then re-apply — is for non-ABS vehicles. With ABS, do not pump.

Question 17 of 25

A Class C CDL is required to drive:

A Class A combinations only
B Any vehicle over 26,001 lbs
C Tractor-trailers under 26,001 lbs GCWR
D Vehicles designed to carry 16+ passengers including the driver, or that require hazmat placards

Correct answer: D

Class C covers vehicles that don't meet Class A or B but are designed to carry 16 or more passengers (including the driver) or carry placarded amounts of hazardous materials.

Question 18 of 25

What is the most important reason for doing a vehicle inspection?

A To reduce tire wear
B To meet your dispatcher's schedule
C Safety for yourself and other road users
D To improve fuel economy

Correct answer: C

Federal rules and the FMCSA model manual list safety as the single most important reason for a pre-trip inspection. Mechanical defects discovered before the trip cannot kill anyone on the highway.

Question 19 of 25

Stopping distance is made up of:

A Reaction distance only
B Perception distance + reaction distance + brake-lag distance + braking distance
C Speed times weight
D Brake-lag distance only

Correct answer: B

Total stopping distance has four parts. Air brakes add a brake-lag distance not present in hydraulic systems.

Question 20 of 25

A driver must report any accident involving a CMV to the carrier within:

A 24 hours
B 7 days
C A reasonable time, before going off duty
D 1 hour

Correct answer: C

FMCSA rules require notification of the motor carrier in a reasonable time — most policies treat that as before going off duty.

Question 21 of 25

A driver convicted of a major offense (DUI, leaving the scene, etc.) in a CMV faces:

A A warning
B No federal consequence
C CDL disqualification for at least one year for a first offense
D A fine only

Correct answer: C

Major offenses carry a one-year CDL disqualification minimum (three years if hauling hazardous materials), and lifetime for a second.

Question 22 of 25

Which of the following is a sign of fatigue?

A Frequent yawning
B All of the above
C Trouble remembering the last few miles
D Drifting in your lane

Correct answer: B

All three are classic fatigue indicators in the FMCSA model. Cold air, music, and caffeine are not effective fixes — only sleep is.

Question 23 of 25

Engine retarders (Jake brakes) should be turned off when:

A Roads are wet, icy, or snow-covered
B In residential areas only because of noise
C Driving in dry conditions
D On any downgrade

Correct answer: A

Retarders can cause drive-wheel skids on slippery surfaces. Turn them off when traction is reduced.

Question 24 of 25

Which is true about driving in rain?

A Roads are most slippery just after rain begins, when water mixes with road oil
B Tire chains are required by federal law
C It is safe to drive at the posted speed limit
D High beams improve visibility in heavy rain

Correct answer: A

The first few minutes of rain mix with oil and grime on the road and create the slipperiest conditions. Slow down and increase following distance.

Question 25 of 25

A leaking exhaust system is dangerous because:

A It causes the engine to overheat
B It can let poisonous carbon monoxide into the cab
C It is illegal
D It increases fuel use

Correct answer: B

Carbon monoxide from a leaking exhaust can cause headaches, drowsiness, and unconsciousness. The illegality is real but the safety risk is the bigger answer.

Study tips for the Minnesota General Knowledge exam

The General Knowledge portion of the Minnesota CDL exam is graded out of the bank of questions the Minnesota Driver and Vehicle Services draws from each year. While the exact bank is not published, every question is sourced from the General Knowledge chapter of the Minnesota CDL handbook, which itself is derived from the FMCSA Model Commercial Driver's License Manual. That means studying our practice tests, reading the corresponding handbook chapter, and re-reading the parts you got wrong is genuinely the most efficient route to a first-time pass.

Most successful applicants follow a simple cycle: take the practice test cold, write down every question you missed, open the matching chapter of the official Minnesota handbook, re-read the section that contains the right answer, then re-take the practice test 24 to 48 hours later. The 24-hour delay matters — sleep is when your brain commits new information to long-term memory, and CDL knowledge questions reward that kind of consolidated learning rather than cramming.

Pay particular attention to questions that include qualifier words like always, never, only, primary, or most. CDL test writers love to flip the right answer with a single qualifier. When two answer choices look almost identical, pay attention to the verb (is it must, should, or may?) and to any numbers (14 days, 100 air miles, 8 hours, 70/8 split). On endorsement tests in particular, watch for trick framing where a true statement about a different endorsement is offered as the "correct" answer to a question that is actually about General Knowledge.

Test-day logistics matter too. Bring photo ID, your Social Security card or birth certificate, your medical examiner's certificate (DOT card), and proof of state residency if you haven't already submitted those documents. The Minnesota Driver and Vehicle Services will not let you sit for the knowledge exam without your documentation, and most offices charge an additional fee for re-attempts. Arrive early — the wait at most CDL testing offices runs 30 to 60 minutes — and silence your phone before the exam begins.

Finally, keep your General Knowledge fundamentals sharp even when you're focused on the General Knowledge exam. Many states administer multiple knowledge tests in a single sitting, and questions on weight definitions (GVWR, GCWR, GAWR), stopping distance, and the pre-trip inspection routine show up across endorsements. If you're unsure on the basics, sit a fresh Minnesota General Knowledge practice test before scheduling the real exam.

Next steps

Missed more than four questions? Re-read the General Knowledge study guide and the matching chapter in the official Minnesota CDL handbook. Then come back and re-take the test. Once you can score 22 of 25 or higher on three runs in a row, you're in good shape to schedule the real exam at your local Minnesota Driver and Vehicle Services office.

Already comfortable with this endorsement? Drill another: MN Air Brakes · MN Combination Vehicles · MN Hazardous Materials · MN Passenger · MN School Bus · MN Tank Vehicle · MN Doubles / Triples

New to the CDL process in Minnesota? Read How to apply for a CDL in Minnesota for the document checklist and step-by-step timeline.