New Hampshire Combination Vehicles CDL Practice Test

This is a free 20-question practice test for the Combination Vehicles portion of the New Hampshire 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 New Hampshire Division 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 New Hampshire.

Question 1 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 2 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 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

Your trailer ABS warning lamp is on. The trailer service brakes:

Will not work at all
Still work normally — only ABS function is unavailable
Lock up
Apply automatically

Correct. Trailer service brakes still work normally without ABS. Have the system repaired; ABS gives extra control during emergency braking.

Question 5 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 6 of 20

When you couple, the locking jaws of the fifth wheel must close around:

The kingpin shank, not just the head
Just the head
The trailer skirt
The wheel

Correct. The locking jaws must engage the kingpin shank below the head. If the jaws close above the head, the connection is unsafe.

Question 7 of 20

Which is the proper following distance for a 60-foot rig at 50 mph?

3 seconds
6 seconds
7 seconds
12 seconds

Correct. 1 second per 10 feet at speeds below 40 mph, plus 1 extra second above 40. 60 feet = 6 seconds + 1 = 7 seconds at highway speed.

Question 8 of 20

Red and amber lights on the rear of the trailer must be:

Working and visible — never broken or covered
Optional
Required only at night
Decorative only

Correct. Brake lights, turn signals, marker lights, and reflectors at the rear must be operational and clean. Damaged or non-working lights are an out-of-service item.

Question 9 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 10 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 11 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 12 of 20

The air lines connecting the tractor and trailer are:

Red (emergency) and blue (service)
Red and yellow
Blue and yellow
Black and red

Correct. The red glad-hand carries emergency/supply air; the blue glad-hand carries service air. They cross to keep matched colors when coupling.

Question 13 of 20

When you are backing a trailer to the right, you should turn the steering wheel:

Left to start the trailer right
Right to start the trailer right
In the same direction every time
Never use the steering wheel; just push

Correct. When backing, the trailer goes opposite to the way you initially turn the steering wheel. To make the trailer go right (passenger side), start by turning the wheel left.

Question 14 of 20

Before uncoupling, you should:

Park on level ground, set the trailer parking brake, lower the landing gear, disconnect air and electrical lines, then release the fifth-wheel jaws
Just pull away
Disconnect electrical only
Drive forward fast

Correct. Proper sequence: park level, lower landing gear to support the trailer, disconnect lines, release jaws, then pull forward slowly. Skipping any step risks dropping the trailer.

Question 15 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 16 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 17 of 20

When you cross railroad tracks in a tractor-trailer, you should:

Shift gears to maintain speed
Cross in a single gear without shifting, and never start across without room to clear the rails
Stop on the tracks if the light turns red
Honk repeatedly

Correct. Crossing in one gear (without shifting) prevents stalling on the tracks. Never enter a crossing unless you can clear it without stopping.

Question 18 of 20

A sliding fifth wheel that is unlocked or improperly secured can:

Slide unexpectedly during braking or acceleration, dangerously changing handling
Improve fuel economy
Save time
Have no effect

Correct. An unsecured sliding fifth wheel can shift during braking, changing the rig's handling unpredictably. Always verify the lock pin is engaged.

Question 19 of 20

A combination vehicle requires more time to stop than a single vehicle because:

It is much heavier and air must travel further to reach the trailer brakes
It accelerates faster
It is shorter
Drivers wait longer

Correct. Greater weight + brake-lag in long air lines = longer stopping distance. Plan ahead.

Question 20 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.

About the New Hampshire 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 New Hampshire Division 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 New Hampshire CDL practice tests.