Nevada Combination Vehicles CDL Practice Test

This is a free 20-question practice test for the Combination Vehicles portion of the Nevada 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 Nevada Department of Motor Vehicles 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 Nevada.

Question 1 of 20

Combination vehicles are usually:

Easier to drive than single trucks
Harder to drive than single trucks because of length, weight, and the unique handling of articulated vehicles
The same as single trucks
Faster than single trucks

Correct. Combination vehicles (tractor-trailer rigs) are heavier, longer, and articulate at the fifth wheel — all making them more demanding than single-unit trucks.

Question 2 of 20

A jackknife happens when:

The trailer wheels skid while the tractor continues forward
The tractor pulls forward in a straight line
The trailer slides sideways while the tractor pivots
The driver brakes too lightly

Correct. Jackknife is when the drive wheels skid and the trailer continues forward, causing the tractor to pivot — the rig folds at the fifth wheel like a closing knife.

Question 3 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 4 of 20

When you connect the glad-hands, you should:

Cross-connect the red and blue lines so they cannot be confused
Connect both to the same color glad-hand
Pinch the seal first
Push them in straight without rotating

Correct. Push the glad-hands together so the rubber seals match, then rotate to lock. Be sure red goes to red and blue goes to blue (the lines themselves often cross to keep colors matched).

Question 5 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 6 of 20

A "trailer skid" happens when:

Trailer wheels lose traction and the trailer slides outward
Tractor wheels lock
Brakes overheat
Cargo shifts

Correct. When trailer wheels lose traction (often from over-application of trailer brakes alone), the trailer can slide sideways — a trailer skid or trailer swing.

Question 7 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 8 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 9 of 20

A trailer that has been sitting may have:

Brakes that need careful adjustment, rust on the kingpin, or other issues that should be inspected
No issues — trailers are static
Built-in safety
Better brakes

Correct. Trailers idle for long periods can develop brake corrosion, kingpin rust, low tires, and other issues. Inspect carefully before use.

Question 10 of 20

A sliding fifth wheel allows you to:

Adjust the weight distribution between drive axles and trailer axles
Speed up
Slow down
Disable the trailer brakes

Correct. Sliding fifth wheels move forward to put more weight on drive axles or aft to reduce drive-axle weight, helping comply with axle-weight limits.

Question 11 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 12 of 20

Trailer rollover is more likely when:

Cargo is loaded low and centered
Cargo is loaded high or to one side, raising the center of gravity
Cargo is light
Trailer is empty

Correct. High cargo and uneven side-loading raise the center of gravity, increasing rollover risk on curves and ramps.

Question 13 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 14 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 15 of 20

When making a turn, you should signal:

Just before the turn
Well in advance — at least 100 feet for a turn at low speed
Only if other vehicles are present
At the start of the turn

Correct. Signal early enough that other drivers see and process the signal — generally at least 100 feet before in town, longer at highway speeds.

Question 16 of 20

Maximum allowable trailer-brake leakage rate (engine off, brakes released, combination vehicle) is:

1 psi/min
3 psi/min
5 psi/min
7 psi/min

Correct. Combination vehicles: no more than 3 psi/min with brakes released, 4 psi/min with brakes applied.

Question 17 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 18 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 19 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 20 of 20

When you supply air to the trailer for the first time after coupling, you should:

Wait until air pressure builds in the trailer reservoir, then test the trailer brakes by pulling out the trailer-supply knob
Drive away immediately
Disconnect the lines
Skip the test

Correct. Charge the trailer system. Then test the trailer brake function by tugging gently or pulling the trailer-supply knob to confirm trailer brakes apply.

About the Nevada 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 Nevada Department of Motor Vehicles 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 Nevada CDL practice tests.