Doubles / Triples (T Endorsement) for the CDL Exam

Common failure modes

These are the patterns that cause most candidates to lose marks on this topic. Recognising them in advance is half the work.

• !Coupling the heaviest trailer at the rear (it must be in front)
• !Misjudging off-tracking on right turns — doubles track several feet inside the tractor path
• !Forgetting the converter dolly inspection items (safety chains, glad-hand seals, kingpin)
• !Underestimating crack-the-whip — the rear trailer can sway at speeds above 50 mph

Study tips

• 1Memorize the coupling order: heaviest trailer in front, lightest in the rear.
• 2Drill off-tracking math: each additional pivot point adds inches to the tracking offset.
• 3Practice the dolly hookup sequence in chronological order — examiners score it.
• 4Know that empty rear trailers crack-the-whip more violently than loaded ones at highway speed.

Sample CDL Doubles / Triples (T Endorsement) questions

These sample items mirror the format and difficulty of real CDL questions. Practice with thousands more on the free Koydo question bank.

1. 1

   When pulling doubles, where should you put the heaviest trailer?

   • AIn the rear, to keep the centre of gravity low
   • BDirectly behind the tractor (the front trailer)Correct
   • CIt does not matter — gross weight is what matters
   • DWhichever trailer was loaded first
   Why this answer?

   The heaviest trailer must be coupled directly behind the tractor. A heavier rear trailer increases the rollover and crack-the-whip risk on the lighter front trailer.