Minnesota General Knowledge CDL Practice Test

This is a free 20-question practice test for the General Knowledge portion of the Minnesota Commercial Driver's License knowledge exam. Questions are pulled from a pool of 97 drawn from the AAMVA CDL Manual, which is the source document the Minnesota Driver and Vehicle Services uses to write its actual exam.

How it works: Click an answer. The correct choice highlights in green, and you'll see a short explanation. Aim for 85% or better before you sit for the real test in Minnesota.

Question 1 of 20

Which of these is the best advice for staying alert on a long trip?

Drink coffee
Take cold pills
Get enough sleep before the trip and take rest breaks
Open the window

Correct. Adequate sleep before driving and scheduled rest breaks are the only reliable strategies. Coffee and cold air mask fatigue but do not eliminate it.

Question 2 of 20

When approaching a curve, you should:

Brake during the curve
Slow down before the curve, then accelerate gently through it
Maintain steady speed
Speed up to maintain control

Correct. Slow before entering the curve. Once in the curve, accelerate gently to maintain stability — braking in a curve invites a skid or rollover.

Question 3 of 20

The "implied consent" rule means:

You agree to chemical testing for alcohol and drugs by holding a CDL and operating a commercial vehicle
Police need a warrant for any test
You may refuse all tests with no penalty
It applies only to passenger cars

Correct. By holding a CDL and operating a CMV on public roads, you have given implied consent to alcohol and drug testing. Refusing testing leads to disqualification just as a positive test does.

Question 4 of 20

How often must drivers inspect their cargo and securing devices?

Within the first 50 miles, then every 150 miles or every 3 hours of driving (whichever comes first)
Only at the start of the trip
Only at fuel stops
Only when entering a new state

Correct. Federal rule: inspect within the first 50 miles, then every 150 miles or 3 hours of driving, whichever comes first, plus every change of duty status.

Question 5 of 20

Which of the following is true about the front-end shock absorbers?

They have nothing to do with handling
Worn shock absorbers can cause poor handling and uneven tire wear
They are part of the brake system
They affect only ride comfort, never safety

Correct. Shock absorbers control suspension oscillation. Worn shocks contribute to poor handling, uneven tire wear, and reduced control on rough roads.

Question 6 of 20

When backing into a tight space, the driver should:

Get out and look (G.O.A.L.) before and during the maneuver
Trust the mirrors only
Back at full speed
Skip the helper

Correct. G.O.A.L. — Get Out And Look — is the universal driver-school rule. When in doubt, stop and look. Use a helper when available.

Question 7 of 20

A "controlled braking" stop is:

Locking the wheels and steering
Applying the brakes hard, just short of wheel lockup
Pumping the brakes
Using the parking brake

Correct. Controlled braking applies the brakes as hard as you can without locking the wheels — used in emergency stops on non-ABS vehicles to retain steering.

Question 8 of 20

What is the only effective way to remove alcohol from the body?

Drinking coffee
Cold showers
Eating a heavy meal
Time

Correct. Only time eliminates alcohol from the body — at roughly one drink per hour. Coffee, food, and showers do not speed up the process.

Question 9 of 20

Which of these is true about following distance for heavy vehicles?

It can be the same as a passenger car
It must be longer because heavy vehicles take longer to stop
It is irrelevant in city driving
It only matters at night

Correct. Greater weight = longer stopping distance. Use one second per 10 feet of vehicle length below 40 mph, plus an extra second above 40.

Question 10 of 20

Which of the following can cause the wheels of your vehicle to skid on a curve?

Driving below the posted speed limit
Driving too fast for the curve
Slowing down before entering the curve
Driving with a light load

Correct. Posted curve advisory speeds assume cars; a heavy commercial vehicle with a high center of gravity may roll over or skid even at the posted speed. Slow before the curve, accelerate gently through it.

Question 11 of 20

You are driving a 60-foot tractor-trailer at 55 mph. The minimum following distance you should maintain is:

4 seconds
5 seconds
6 seconds
7 seconds

Correct. Above 40 mph, add one extra second to the per-10-foot rule. A 60-foot vehicle = 6 seconds + 1 = 7 seconds at 55 mph.

Question 12 of 20

What is the minimum tread depth required for the front (steering) tires of a commercial vehicle?

1/32 inch
2/32 inch
4/32 inch
6/32 inch

Correct. Steer-axle tires must have at least 4/32-inch tread depth in every major groove. Other tires require at least 2/32 inch.

Question 13 of 20

You are driving on a two-lane road. An oncoming driver drifts into your lane. You should:

Steer right onto the shoulder
Flash your high beams
Honk your horn
Brake hard and stop in your lane

Correct. When an oncoming driver drifts into your lane, the safer escape is right onto the shoulder. Steering left risks a head-on if the other driver corrects.

Question 14 of 20

When driving down a long, steep downgrade, you should:

Hold the brakes lightly the whole way down
Select the proper gear before starting down and use intermittent firm brake applications
Coast in neutral
Use only the engine brake

Correct. Select a low gear before starting down. Use the brakes in firm, intermittent applications: brake until 5 mph below safe speed, release until safe speed is regained, repeat. Continuous brake application overheats the brakes.

Question 15 of 20

The four-way flashers on a commercial vehicle should be used:

Anytime you are stopped or moving slowly enough that other drivers might not expect
Only when parked
Only at night
Only on the interstate

Correct. Use four-way flashers anytime your vehicle is stopped on or near the roadway, or moving slowly enough that approaching traffic might be surprised.

Question 16 of 20

The blood-alcohol concentration (BAC) at or above which a CDL driver is considered to be driving under the influence in a commercial motor vehicle is:

Correct. The federal BAC limit for CDL drivers operating a commercial vehicle is .04 — half the .08 limit for non-commercial drivers in most states.

Question 17 of 20

Which of these statements about backing a heavy vehicle is true?

Backing is always safe if you go slow
Whenever possible, use a helper outside the vehicle to guide you
Always back from the right side because you can see better
Backing is the same as backing a car

Correct. Backing is always risky for heavy vehicles. Use a helper, communicate with hand signals agreed in advance, back slowly, and if alone, get out and look (G.O.A.L.).

Question 18 of 20

Which lane is generally the best for a commercial vehicle on a multi-lane highway?

The far left (passing) lane
The middle lane
The right lane (slow lane)
Whichever has the lightest traffic

Correct. The right lane is generally best — it limits lane changes, reduces conflict with merging traffic only on the right, and matches commercial-vehicle speed.

Question 19 of 20

When the brake pedal feels spongy on an air-brake vehicle:

It is normal
Stop and have the system checked — there may be air in the system or another issue
Drive faster
Pump the brakes harder

Correct. A spongy or unusual feel in air-brake pedals indicates a system issue. Have it inspected before continuing.

Question 20 of 20

Which of the following is a cab in-vehicle inspection item?

Steering wheel free play
Headlights
Tire condition
Lug nuts

Correct. Steering-wheel free play is checked from the driver seat and should not exceed 10 degrees (about 2 inches on a 20-inch wheel).

About the Minnesota General Knowledge exam

Most state DMVs administer 50 General Knowledge questions and require 80% (40 correct) to pass. Questions are pulled from a much larger pool, so two applicants taking the test on the same day will see different mixes. The questions on this site are drawn from the AAMVA CDL Manual chapters that every state's exam is built from.

The Minnesota Driver and Vehicle Services follows the federal CDL standards established by FMCSA. To earn the General Knowledge credential, you must answer at least 80% of the questions correctly. Many candidates score lower the first time because the test pulls from a large pool — refreshing this page will give you a different mix of questions, drawn from the same authoritative source.

Want more practice? Try the full General Knowledge question bank or browse all Minnesota CDL practice tests.