Practice question Which federal rule lists required doubles/triples knowledge areas? A passenger endorsement onlyA cargo paperwork shortcutAn action not supported by DPS Section 749 CFR 383.115 Answer: D — 49 CFR 383.115 The correct answer is shown above. Try the full quiz for additional practice. Practice more: TX CDL Doubles and Triples Practice Questions - Texas CDL Doubles and Triples Endorsement Test Exam →