T
Washington Endorsement
CDL endorsement code T
Required to pull two or three trailers behind a Class A combination vehicle.
What it covers
The Doubles/Triples (T) endorsement is required to operate a Class A combination vehicle pulling more than one trailer. Triples are not legal in every state.
Federal requirements
- Hold a Class A CDL.
- Pass the Doubles/Triples knowledge test (~20 questions).
- No skills test required.
- No TSA background check required.
Source: 49 CFR §383.93(c)(1)
Fees
Knowledge-test fee only.
How to study
- Read the Doubles/Triples section of your state CDL manual.
- Memorize coupling and uncoupling procedures, off-tracking, and rearward amplification ("crack the whip").
- Know which states allow triples — many do not.
- Practice with the Doubles/Triples practice test inside your state's page.
Take the Washington practice test
State-specific practice tests live inside each state hub. Pick yours:
FAQ
Are triple trailers legal in every state?
No. Most states limit configurations to single or double trailers on most highways. Check your state's rules before driving triples.
Does T require ELDT?
No — T is not in the ELDT-required endorsement list.