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SESK: Stuff Everyone Should Know · sesk.info/cdl-endorsement-t-doubles

Which CDL endorsement letter lets you pull double or triple trailers?

T, for double/triple trailers.

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  1. D
  2. T ✔
  3. X

Why: The federal code for the double/triple trailers endorsement is T. You get it by passing a knowledge test only, with no extra skills test.

Huh, didn't know that: Triples are legal only on certain highways in some states.

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Why are doubles drivers fun at parties? They always bring a plus-one.
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References

Answer: T. The federal code for the double/triple trailers endorsement is T. You get it by passing a knowledge test only, with no extra skills test.

  1. 49 CFR 383.153 Information on the CLP and CDL documents (eCFR) www.ecfr.gov/current/title-49/section-383.153
    T for double/triple trailers
    Checked 2026-10-10.
  2. California Commercial Driver Handbook (DMV) www.dmv.ca.gov/portal/file/california-commercial-driver-handbook-pdf
    The CDL holder must pass a special knowledge examination on the problems associated with pulling multiple trailers.
    Checked 2026-10-10.

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