Utah Doubles/Triples CDL Practice Test

This is a free 20-question practice test for the Doubles/Triples portion of the Utah Commercial Driver's License knowledge exam. Questions are pulled from a pool of 50 drawn from the AAMVA CDL Manual, which is the source document the Utah Driver 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 Utah.

Question 1 of 20

When coupling the second trailer to the converter dolly:

Position the dolly in front of the second trailer, lower trailer landing gear if necessary, lock the dolly to the lead trailer's pintle hook with safety chains, then back the second trailer onto the fifth wheel
Just push them together
Use the trailer hand valve
Drive past it fast

Correct. Position dolly, secure to lead-trailer pintle, then back second trailer over the fifth wheel and lock as a normal coupling.

Question 2 of 20

In a multi-trailer combination, the most violent movement during evasive maneuvers happens at:

The tractor
The first trailer
The last trailer
The cab

Correct. Rearward amplification (crack-the-whip effect) is greatest at the rear-most trailer. The last trailer in a triple can be thrown sideways with much greater force than the tractor.

Question 3 of 20

The "T" endorsement is required to:

Drive any commercial vehicle
Pull two or more trailers
Drive a bus
Haul hazmat

Correct. The T endorsement is required to pull more than one trailer (doubles or triples).

Question 4 of 20

When pulling a single trailer and trying to figure out if you should add a doubles endorsement:

You only need T if you actually pull more than one trailer
T is required for any commercial driving
T is required only for tankers
T is required for any class A driver

Correct. The T endorsement is required only when you actually operate doubles or triples. Single-trailer operations do not require it.

Question 5 of 20

Before connecting a converter dolly, you should:

Inspect tires, brakes, fifth-wheel jaws, and overall condition
Skip inspection
Only check the tires
Only check the lights

Correct. Pre-trip the dolly: tires, brake adjustment, fifth-wheel jaws (open and clean), pintle hook, electrical receptacle, lights.

Question 6 of 20

A "set of doubles" typically refers to:

A tractor pulling two trailers
One tractor with one long trailer
Two tractors and a trailer
Two tractors and two trailers

Correct. A "set of doubles" is one tractor pulling two trailers (typically two pups, each about 28 feet long, in LTL operations).

Question 7 of 20

When backing a doubles or triples combination:

Avoid it whenever possible — multi-trailer rigs cannot be backed any meaningful distance safely
Back at full speed
Back without a helper
Use only the trailer brake

Correct. Doubles and triples cannot be backed safely beyond a few feet — joints flex unpredictably. Plan your route and parking to avoid backing.

Question 8 of 20

When making a lane change in a doubles rig, you should:

Signal early, check mirrors, change lanes gradually
Snap the wheel
Use only the trailer hand valve
Skip the signal

Correct. Early signal, mirror check, gradual lane change. Quick lane changes amplify into the rear trailer.

Question 9 of 20

A driver licensed for Class A with all endorsements may drive any combination vehicle. The T endorsement allows:

Doubles and triples
Hazmat
Tanker
Buses

Correct. T endorsement specifically authorizes doubles and triples. Other endorsements (H, N, P, S) cover other categories.

Question 10 of 20

A "set of triples" typically refers to:

One tractor pulling three trailers
Three trailers without a tractor
Three tractors and one trailer
Three tractors only

Correct. A set of triples is one tractor pulling three trailers — usually allowed only on specific designated routes.

Question 11 of 20

On a steep downgrade with doubles, you should:

Select a lower gear before starting down and use intermittent firm braking
Coast in neutral
Use only trailer brake
Stay in high gear

Correct. Same rule as any combination vehicle, but plan extra margin: doubles take longer to stop and the rear trailer may push.

Question 12 of 20

During a pre-trip on doubles, the trailer-supply line:

Should be open from tractor to rear-most trailer
Should be open at the front but closed at the rear-most trailer
Should be closed everywhere
Should always be disconnected

Correct. The supply line carries air from tractor through every trailer; verify open valves at every coupled connection and a closed valve at the rear of the rear-most trailer.

Question 13 of 20

Crosswinds are particularly hazardous for:

Empty doubles and triples
Loaded singles
Backing
Slow speeds

Correct. Empty trailers in a multi-trailer rig present a large flat surface to crosswinds — a strong gust can blow the rear trailer over.

Question 14 of 20

When inspecting a doubles or triples rig, you should additionally check:

Each pintle hook, each set of safety chains, each converter dolly, each trailer's lights, brake chamber connections, glad-hands, and shut-off valves
Only the lead trailer
Only the tractor
Only the cargo

Correct. Every connection point and every trailer needs inspection — pintle hooks, chains, dollies, lights, brake lines, glad-hands, and air-supply valves.

Question 15 of 20

When pulling triples, you should:

Make abrupt lane changes
Drive in the right lane and avoid abrupt steering
Drive in the left lane
Drive at top speed

Correct. Stay right, plan lane changes well in advance, signal early, and avoid abrupt steering. Triples crack-the-whip violently.

Question 16 of 20

Safety chains on a converter dolly are required to:

Prevent the dolly from disconnecting if the pintle hook fails
Decorate the rig
Bind cargo
Add weight

Correct. Safety chains catch the dolly if the pintle hook releases or fails — preventing the trailer behind from breaking loose.

Question 17 of 20

Air pressure on a triple-trailer rig takes:

Less time to reach the rear trailer than on a single
Significantly more time to reach the rear trailer's brake chambers
The same time
No air pressure is needed

Correct. Each additional trailer adds line length. Brake response at the rear trailer of a triple is noticeably delayed — brake earlier.

Question 18 of 20

Doubles and triples should not be driven:

On slippery roads at normal speed
On dry, straight highways
In any conditions
Only at low speed

Correct. On slippery roads, multi-trailer rigs lose stability quickly. Reduce speed substantially and increase following distance.

Question 19 of 20

When pulling a heavy lead trailer and a light second trailer, the rig:

Will be more stable than the reverse
Is more likely to roll the rear trailer
Is illegal
Drives the same as either order

Correct. Heaviest in front, lightest in rear. Heavy at the rear amplifies crack-the-whip and rollover risk.

Question 20 of 20

The driver of a doubles rig should:

Make slow, gradual steering and braking inputs
Drive aggressively
Use only the trailer brake
Honk frequently

Correct. Smooth, gradual inputs are critical. Avoid abrupt steering and abrupt braking.

About the Utah Doubles/Triples exam

Most states administer 20 Doubles/Triples questions and require 80% to pass. The exam emphasizes coupling and uncoupling the converter dolly, rearward amplification (the "crack-the-whip" effect), and the unique inspection and handling demands of multi-trailer rigs.

The Utah Driver License Division follows the federal CDL standards established by FMCSA. To earn the Doubles/Triples 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 Doubles/Triples question bank or browse all Utah CDL practice tests.