California CDL Doubles and Triples Endorsement Test study plan

List the full coupling sequence for a tractor to a converter dolly and first trailer from memory, in order, without notes.

Identify and name each coupling component (fifth wheel, kingpin, landing gear, glad hands, safety latch, air lines, electrical cord) and state its inspection criteria.

Demonstrate a pre-trip walk-around inspection order for a doubles/triples combination and justify why each check happens where it does.

Explain the consequences of coupling with a misaligned fifth wheel or an unlatched kingpin, in terms of what physically fails.

Recite the uncoupling sequence for both the dolly and the rear trailer, including where to chock and when to release air.

Diagnose five common coupling faults (high hook, low hook, twisted dolly, crossed air lines, missing safety latch) and state the correction for each.

Perform and narrate a full inspection of a converter dolly: pintle hook, lunette eye, drawbar, safety chains, air lines, and tires.

Describe the correct procedure for checking that the trailer is locked to the fifth wheel by tugging, and explain why a visual check alone is insufficient.

Summarize the handling differences between pulling one trailer and pulling two or three, covering off-tracking, sway, and rearward amplification.

Define rearward amplification and explain how it grows with each added trailer and with speed.

Explain why the last trailer in a set swings widest and how that changes lane positioning and mirror use.

List the stability rules for doubles/triples operation, including load placement, speed reduction, and avoiding abrupt steering.

Describe the function of the converter dolly and name its failure points, including the pintle hook and lunette eye wear limits.

Explain how to connect and disconnect air lines and electrical cords on a dolly, and the order in which they are handled.

Identify the causes of trailer swing and converter dolly sway, and state the corrective action for each.

Explain why the heaviest load goes on the lead trailer and how that affects dolly stability.

Explain why total stopping distance grows with each trailer and describe how to adjust following distance and brake application accordingly.

Describe the correct response to a jackknife or trailer swing, including which way to steer and when to release the brakes.

Explain the use of the trailer hand valve and why it must never be used for parking.

Describe how to negotiate a curve with multiple trailers: speed before entry, lane position, and mirror checks through the turn.

Define offtracking and state how much extra road space a triple needs in a tight turn.

Calculate a safe following distance for a triple at 55 mph and justify the number in seconds.

Explain how speed affects rearward amplification and state the practical speed limit for doubles/triples operation.

Describe how to plan a lane change with a triple, including mirror sequence, signal timing, and the space needed for the last trailer to clear.

Explain how to handle a downgrade with multiple trailers, including gear selection and brake use.

List the California-specific legal requirements for doubles/triples operation, including weight limits, length limits, and permitted routes.

State the cargo securement requirements for multiple trailers, including tie-down count and working load limits.

Explain how to distribute weight across a triple set to keep each axle within limits and maintain stability.

Describe the inspection and documentation duties that apply before and during a doubles/triples trip.

Complete a full-length timed practice test covering all eight domains and score each domain separately.

Re-study the two weakest domains until each practice score rises by at least 15 percentage points.

Recite the coupling and uncoupling sequences cold, with no notes, in under five minutes each.

Review every missed question and write the reason for the correct answer in your own words.