CDL Doubles and Triples Practice Test 2 — Questions and Answers
Question 1: When coupling a second trailer, where should the converter dolly be positioned in relation to the first trailer?
- In line with and directly behind the rear of the first trailer (Correct answer)
- Off to one side of the first trailer
- Tilted at a 45-degree angle
- As far back as the parking lot allows
Correct answer: In line with and directly behind the rear of the first trailer
The dolly must line up directly behind the first trailer so the second trailer's kingpin can seat properly.
Question 2: How should you check that a converter dolly's pintle hook is properly latched?
- By looking for the safety latch to be closed and locked (Correct answer)
- By honking the horn twice
- By checking the trailer lights
- By feeling the brake pedal
Correct answer: By looking for the safety latch to be closed and locked
The pintle hook must be fully closed with its safety latch engaged to keep the dolly connected.
Question 3: Which trailer should generally be loaded with the heaviest cargo in a set of doubles?
- The front trailer, closest to the tractor (Correct answer)
- The rear trailer
- It does not matter
- Always split the weight exactly even regardless
Correct answer: The front trailer, closest to the tractor
Heavier cargo goes in the front trailer to improve stability and reduce rearward crack-the-whip effect.
Question 4: What is the 'crack-the-whip' effect in doubles and triples?
- The rear trailer swings more sharply than the tractor, increasing rollover risk (Correct answer)
- The brakes lock up in cold weather
- The tractor stalls on hills
- The trailers separate at high speed
Correct answer: The rear trailer swings more sharply than the tractor, increasing rollover risk
Rapid steering causes the rear trailer to swing wider and more violently, raising the chance of a rollover.
Question 5: Before uncoupling a converter dolly, what should you do first?
- Lower the dolly support and chock or secure the trailers (Correct answer)
- Drive forward quickly to release tension
- Disconnect the air lines while moving
- Release all trailer brakes
Correct answer: Lower the dolly support and chock or secure the trailers
Securing the trailers and lowering the dolly support prevents rollaway and injury during uncoupling.
Question 6: How much greater is the stopping distance and braking demand on a doubles/triples combination compared to a straight truck?
- It requires more room and earlier braking due to greater length and weight (Correct answer)
- It stops in half the distance
- It is exactly the same
- It needs no extra space
Correct answer: It requires more room and earlier braking due to greater length and weight
Longer, heavier combinations need more distance and earlier braking to stop safely.
Question 7: What should you do with the converter dolly's air tank drain before coupling in cold weather?
- Drain any water to prevent the brakes from freezing (Correct answer)
- Fill it with antifreeze
- Leave it pressurized at all times
- Remove the tank entirely
Correct answer: Drain any water to prevent the brakes from freezing
Draining water from the dolly air tank prevents ice from blocking the brake system in freezing temperatures.
CDL Doubles and Triples Practice Test 2
When coupling a second trailer, where should the converter dolly be positioned in relation to the first trailer?