Oklahoma Doubles/Triples CDL Practice Test

This is a free 20-question practice test for the Doubles/Triples portion of the Oklahoma 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 Service Oklahoma Driver License 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 Oklahoma.

Question 1 of 20

When pulling doubles in a tunnel:

Stay alert; clearance and turning radius can be tight
Drive faster
Stop in the middle
Honk continuously

Correct. Tunnel clearance can be tight for long doubles — watch overhead and side clearance, and respect any vehicle-class restrictions.

Question 2 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 3 of 20

Glad-hand shut-off valves at the rear of trailers (for connecting to a following trailer) must be:

Open at the rear of the rear-most trailer
Open at the rear of any trailer that has another trailer behind it; closed at the rear of the last trailer
Always closed
Always open

Correct. Open the shut-off valves where the next trailer is connected; close them at the rear of the last trailer to prevent air loss.

Question 4 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 5 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 6 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 7 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 8 of 20

When inspecting a converter dolly, the pintle hook must:

Lock fully closed around the lunette eye
Be loose
Be cracked
Be replaced quarterly

Correct. The pintle hook must close fully around the lunette eye, with no excessive wear or cracks. Add safety chains as backup.

Question 9 of 20

When parking a doubles rig:

Park where you can pull straight out — back-out is impractical
Back into any spot
Park in the entrance
Block the lane

Correct. Choose pull-through parking. Multi-trailer rigs cannot back any meaningful distance safely.

Question 10 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 11 of 20

A tractor pulling doubles cannot brake as quickly as a tractor pulling a single trailer because:

Doubles are heavier and brake response is delayed in longer air lines
Doubles are lighter
Brakes are bigger
Tractors brake better with doubles

Correct. Greater weight and longer air lines mean longer braking distance. Plan stopping distance with extra margin.

Question 12 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 13 of 20

When you uncouple a converter dolly, you should:

Disconnect air and electrical, secure or remove safety chains, then release the pintle hook
Just yank it off
Drive forward fast
Use only the trailer brake

Correct. Park level, disconnect air and electric, lower trailer landing gear if applicable, remove safety chains, then release the pintle hook to free the dolly.

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 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 16 of 20

Inspecting safety chains on a converter dolly:

Verify they are correctly crossed and have no broken links, deformations, or wear
Skip the chains
Replace them daily
Verify color only

Correct. Safety chains should be intact, no broken links or excessive wear, and properly crossed under the pintle for support.

Question 17 of 20

When testing the brakes on a doubles rig:

Do all the standard checks plus verify air pressure builds at the rear trailer and that brakes apply at all wheels
Only test the tractor
Only test the lead trailer
Skip the test

Correct. Test the entire rig: build-up time, leakage, low-pressure warning, parking brake, and confirm rear-trailer brake function.

Question 18 of 20

A converter-dolly fifth wheel must be:

Properly lubricated and have correctly functioning locking jaws
Painted
Wide
Empty

Correct. Inspect for proper lubrication, no excessive wear, and confirm the locking jaws operate correctly. The dolly fifth wheel is just as critical as the tractor's.

Question 19 of 20

Drivers should always couple the heaviest trailer:

Behind the tractor (in the front position)
At the rear
In the middle
It does not matter

Correct. Heaviest trailer goes directly behind the tractor; lightest goes at the rear. This minimizes rearward amplification and rollover risk.

Question 20 of 20

When traveling on bridges with weight or length limits:

Verify the rig's overall length and weight comply with posted limits
Ignore signs
Drive faster
Honk the horn

Correct. Multi-trailer rigs may exceed length or weight limits on certain bridges. Plan routes to comply with posted limits.

About the Oklahoma 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 Service Oklahoma Driver License Services 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 Oklahoma CDL practice tests.