Oregon Doubles & Triples (T) Practice Test

The endorsement for pulling two or three trailers. The test targets what changes when you add trailers: the crack-the-whip effect that amplifies every steering input at the last trailer, why the lightest trailer belongs in the rear, converter dollies and how coupling doubles differs from coupling a single, and the longer gaps and slower decisions that stability demands. It's knowledge-test-only — there's no separate skills test — but several states won't let you pull triples at all, so where you can use it depends on where you drive.

Who needs it: LTL linehaul and turnpike drivers pulling sets. Knowledge test only — no separate skills exam.

Sample practice questions

When inspecting the coupling system, there should be:

Answer: No space in the couplings, with locking jaws closed on the kingpin — No gaps and closed jaws mean the couplings are locked; check fifth wheels, pintle hooks, and safety chains too.

Glad hands are:

Answer: Air-line coupler fittings that must be clean and seal properly — Glad hands join the air lines; keep them clean, sealing, and not crossed.

After the dolly is under and locked to the rear trailer, you connect:

Answer: Safety chains, air hoses (glad hands), and the light cord — Connect the safety chains, the air hoses (glad hands), and the electrical/light cord between the dolly and the rear trailer.

Common mistakes on the Doubles/Triples test

  • Putting the heaviest trailer in the rear — the test (and physics) wants it behind the tractor
  • Forgetting the dolly coupling sequence and the extra air-line connections doubles require
  • Ignoring rearward amplification — the last trailer can flip from an input the tractor barely felt
  • Assuming triples are legal everywhere — several states prohibit them entirely

The Doubles & Triples (T) endorsement has no federal ELDT requirement — it's a knowledge test only, so practice is the whole game.

Official source: Oregon Driver & Motor Vehicle Services (ODOT)

CDL licensing in Oregon is administered by the Oregon Driver & Motor Vehicle Services (ODOT). Fees, scheduling, forms, and the official Oregon CDL manual live on the official site: Oregon DMV — official CDL page (verified 2026-08-09).

Truckcess is not affiliated with or endorsed by the Oregon Driver & Motor Vehicle Services (ODOT). Our practice tests cover the federal CDL knowledge standards (49 CFR Part 383) that every state exam is built on; exact question counts, fees, and procedures vary by state and change over time — the official site is always the authority.

More Oregon practice tests

Full prep courses are one-time from $59 with 12 months of access — mytruckcess.com/cdl.

CDL practice tests by state · Meet the Course Director · The completion certificate