North Dakota Combination Vehicles CDL Practice Test

This is a free 20-question practice test for the Combination Vehicles portion of the North Dakota Commercial Driver's License knowledge exam. Questions are pulled from a pool of 55 drawn from the AAMVA CDL Manual, which is the source document the North Dakota Department of Transportation Drivers License Division 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 North Dakota.

Question 1 of 20

Off-tracking refers to:

Trailer brakes overheating
Trailer wheels following a tighter path than the tractor wheels in turns
The trailer pulling left
Tires losing tread

Correct. Off-tracking is the tendency for trailer wheels to follow a smaller-radius path than the tractor wheels through a turn, more pronounced with longer wheelbases.

Question 2 of 20

A sliding-tandem trailer allows you to:

Adjust the trailer-axle position to redistribute weight between trailer axles and tractor drive axles
Speed up
Cool the load
Steer the trailer

Correct. Sliding tandems shift trailer axles forward (more weight on tractor) or aft (more weight on trailer axles), helping meet axle-weight limits.

Question 3 of 20

When making a right turn at an intersection in a tractor-trailer:

Swing to the left first to make room for the right turn
Make the turn from the right lane and swing wide as needed at the end of the turn
Make the turn at high speed
Stay in the left lane through the turn

Correct. Make the turn from the right lane. If you must swing wide, do so as you complete the turn, never before — swinging left first invites a vehicle to pass on your right.

Question 4 of 20

The most likely cause of a tractor jackknife is:

Light cargo
Drive wheels lock during braking
Slow speed
Loose load

Correct. When drive wheels lose traction (locked, oversteer, ice), the tractor pivots ahead of the trailer — a jackknife.

Question 5 of 20

A combination vehicle on slippery roads should be driven:

Faster to maintain control
Slower with greater following distance
At normal speed
In a higher gear

Correct. Reduce speed by at least one third on wet roads and one half on snow; double following distance on slick surfaces.

Question 6 of 20

To recover from a trailer skid, you should:

Apply more brakes
Release the brakes to let the trailer wheels regain traction
Steer hard left
Honk

Correct. Release the brakes so the trailer wheels can rotate again and re-establish traction. Continued braking will worsen the skid.

Question 7 of 20

A loaded trailer "bows" (sways) at speed because:

Air pressure changes
Crosswinds, road bumps, or heavy rear loading can produce trailer sway
Tires wear
Brakes are applied

Correct. Crosswinds and uneven loading can produce trailer sway. Slow down and allow the sway to dampen; do not over-correct with steering.

Question 8 of 20

When approaching a curve in a tractor-trailer, you should:

Brake during the curve
Slow down before entering the curve
Speed up
Maintain steady speed

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

Question 9 of 20

A high-mounted trailer kingpin is dangerous because:

It will not engage the fifth wheel and the trailer can drop
It is illegal
It improves coupling
It changes color

Correct. If the trailer is too high, the fifth wheel slides under without the kingpin engaging the locking jaws. The trailer is not coupled and can drop when you pull away.

Question 10 of 20

When coupling, after backing under the trailer, you should:

Pull the trailer immediately
Perform a tug test (gently pulling forward in low gear with trailer brakes set) to confirm the kingpin is locked
Disconnect the air lines
Lower the landing gear

Correct. A tug test confirms the kingpin is fully engaged. Skipping it is the leading cause of trailer drops shortly after coupling.

Question 11 of 20

When you check the fifth wheel during pre-trip, you look for:

Mounting to the frame is secure, no missing or damaged parts, no visible space between the upper and lower fifth-wheel plates, locking jaws around the kingpin shank, release arm in the locked position
Only the color
Only the bolts
Only the grease

Correct. Check mount, condition, gap, jaw engagement around kingpin shank (not the head), and release-arm lock position. Lubrication should be present but not excessive.

Question 12 of 20

A combination-vehicle pre-trip should include:

All single-vehicle items plus fifth wheel, kingpin, sliding fifth wheel/sliding tandem locks, mud flaps, trailer brakes, lights, and trailer tires
Only the tractor
Only the trailer
Only the cargo

Correct. You inspect the entire rig — tractor + trailer + connections + cargo securement — not just the tractor.

Question 13 of 20

On a tight curve or exit ramp, a tractor-trailer is most likely to roll over because:

The trailer brakes lock
The high center of gravity creates a tipping force greater than the tires can resist
The tractor accelerates
The road is dry

Correct. Centripetal forces in a curve push the cargo outward; a high center of gravity multiplies the tipping moment. Slow before the curve.

Question 14 of 20

When backing a tractor-trailer in a straight line, you should:

Let the trailer drift wherever it goes
Make small steering corrections to keep the trailer in line
Apply heavy brake pressure
Use the trailer hand valve

Correct. When backing straight, watch the trailer in your mirrors and make small steering corrections to keep it tracking straight. Big corrections lead to jackknifing.

Question 15 of 20

Most jackknifes happen because:

Drive wheels skid during braking on slippery surfaces
Brakes work too well
The road is dry
Cargo is too light

Correct. Loss of traction on the tractor drive axles during braking — typically on slick surfaces or with overly aggressive braking — causes a jackknife.

Question 16 of 20

Before backing under a trailer to couple, you should:

Check that the trailer height is just below the fifth wheel so the fifth wheel will lift the trailer slightly when backed under
Set the trailer at any height
Lock the trailer brakes off
Disconnect the air lines

Correct. Trailer should be just low enough that the fifth wheel will lift it slightly. Too low: the fifth wheel hits the trailer body. Too high: the fifth wheel slides under without engaging the kingpin.

Question 17 of 20

Length and weight increase what about a combination vehicle?

Stopping distance, off-tracking, blind spots, and time required for lane changes
Visibility
Speed
Acceleration

Correct. Longer, heavier rigs need more stopping distance, swing wider in turns, have larger blind spots, and require more time and space to change lanes.

Question 18 of 20

Cargo securement: the heaviest part of the load should be:

Loaded over the front axle area, with weight evenly distributed side to side
Loaded at the rear
Loaded on one side
Stacked on top

Correct. Loading heavy cargo to the front of the trailer over the drive axles helps with traction; loading to one side or top creates dangerous handling.

Question 19 of 20

When you "G.O.A.L." in trucking, you:

Get Off And Look — visually verify the area before backing
Go Over A Limit
Grab On And Lift
Greet Other Approaching Loaders

Correct. G.O.A.L. — Get Out And Look — is the universal driver-school rule before any tight backing maneuver.

Question 20 of 20

When inspecting the kingpin during pre-trip, look for:

Excessive wear, bending, cracks, or improper lock-jaw engagement
Only the color
Only the size
Only the grease

Correct. A worn, cracked, or bent kingpin can fail under load. The locking jaws must close completely around the shank, not just the head.

About the North Dakota Combination Vehicles exam

Most states administer 20 Combination Vehicles questions and require 80% to pass. The exam emphasizes the unique handling of articulated vehicles: how trailers track behind the tractor, how to prevent rollover, how to manage rearward amplification with multi-trailer combinations, and the correct sequence to couple and uncouple.

The North Dakota Department of Transportation Drivers License Division follows the federal CDL standards established by FMCSA. To earn the Combination Vehicles 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 Combination Vehicles question bank or browse all North Dakota CDL practice tests.