California Commercial Learner's Permit & CDL Preparation California CDL Commercial Handbook
Doubles and triples

Inspect every connection and slow before the combination becomes unstable.

Prepare converter-dolly coupling, inspection, crack-the-whip, rollover, emergency handling and multiple-trailer operation.

Knowledge endorsement

The T endorsement is added by knowledge testing for drivers operating double or triple trailers where lawful. It is not a CLP endorsement for practice driving.

Primary risks

Rearward amplification, rollover, tracking, converter-dolly security, pintle hooks, safety chains, air lines, electrical lines and uncoupling sequence.