Doubles / Triples practice test
The endorsement for pulling two or three trailers.
The Doubles and Triples endorsement ('T') allows a driver to pull two or three trailers at once. It is the least common endorsement, because not every state allows doubles and triples at all, and the ones that do set their own rules about where and when. The test covers the handling of a double or triple combination: that it is even longer and harder to control than a single trailer, that it turns more widely and backs differently, that the rear trailer can swing wide on a turn, and how a triple's weight is distributed across its axles. It is written to the federal knowledge areas every state is required to test. This bank ships after the three launch banks are live. Every item here is written for this site and carries its full explanation, free.
Doubles / Triples
This bank ships soon. The test covers the concepts in this page’s description, and your state’s manual is the thing to study.
These questions are written to the federal knowledge areas every state is required to test. They are not your state's questions — no free site has those. Your state writes its own test from its own CDL manual, and that manual is the thing to study.
All the tests
The requirement matrix on the home page computes which of the eight you need.
This site prepares for a written knowledge test. It is not driver training, it is not ELDT, and nothing on it substitutes for your state's CDL manual or a registered training provider. Air brake procedure, coupling, load securement and hazardous-materials handling are safety-critical, and this site never teaches them as something to do.