What are doubles and triples in trucking?
Hauling doubles or triples means you’re pulling two or three trailers with the same tractor. As you’ve probably already guessed, a doubles and triples endorsement is the certification drivers need to pull that type of load.
How do you pass doubles and triples test?
The California doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%)….CA CDL Doubles Triples Test.
| Number of questions: | 20 |
|---|---|
| Correct answers to pass: | 16 |
| Passing score: | 80% |
When you’re pulling doubles or triples the shut off valves should always be?
When pulling two or more trailers, the shut off valves on the first trailer should be in the following positions: The service line should be closed and the emergency line should be open. The service line should be open and the emergency line should be closed.
What is the correct order of steps for uncoupling double trailers?
Knowing how to couple and uncouple correctly is basic to the safe operation of combination vehicles….6.3 Coupling and Uncoupling
- STEP 1: Inspect Fifth Wheel.
- STEP 2: Inspect Area and Chock Wheels.
- STEP 3: Position Tractor.
- STEP 4: Back Slowly.
- STEP 5: Secure Tractor.
How long is a truck with doubles?
28 feet
Double or pup trailers are typically 28 feet in length, while intermodal containers can be 20 or 40 feet. Tanker trailers, flatbeds and a wide variety of other trailer types are available, all in slightly different lengths.
How many questions are on the CDL doubles test?
The test consists of 20 multiple choice and true/false questions. You must get a score of 80% to pass (16 questions answered correctly.) You can prepare for the doubles/triples written test by studying the appropriate section of the CDL Manual and taking some free practice tests.
When driving a double or triple you need more space because they?
7.1. Doubles and triples take up more space than other commercial vehicles. They are not only longer, but also need more space because they can’t be turned or stopped suddenly. Allow more following distance. Make sure you have large enough gaps before entering or crossing traffic.
When pulling double or triple trailers which shut-off valves should be open and which shut-off valves should be closed?
The valves on the back of the first trailer should be open, the valves on the rear of the second trailer should be closed. Question 14: On the rear of your last trailer are two air shut-off valves. How can you enurse air is flowing through the system?
What 3 methods can you use to secure a second trailer before coupling?
What three methods can you use to secure a second trailer before coupling? 1) Connect the emergency line, charge the trailer air tank, and disconnect the emergency line. 2) Spring brakes. 3) Wheel chocks.
Is it dangerous to coupling and uncoupling double trailers?
Wrong coupling and uncoupling can be very dangerous. Coupling and uncoupling steps for doubles and triples are outlined below. If the second trailer does not have spring brakes, drive the tractor close to the trailer, connect the emergency line, charge the trailer air tank, and disconnect the emergency line.
What should I do if my tractor coupling is wrong?
Wrong coupling and uncoupling can be very dangerous. Coupling and uncoupling steps for doubles and triples are listed below. If the second trailer doesn’t have spring brakes, drive the tractor close to the trailer, connect the emergency line, charge the trailer air tank, and disconnect the emergency line.
How do you test coupling on a semi trailer?
Test coupling by pulling against pin of number two semi-trailer. Make visual check of coupling no space between upper and lower fifth wheel. Locking jaws closed on kingpin). Connect safety chains, air hoses and light cords. Close converter dolly air tank petcock and shut-off valves at rear of second trailer (service and emergency shut-offs).
Which is the correct position for coupling a double bottom trailer?
A converter gear or dolly is a coupling device of one or two axles and a fifth wheel by which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig. Caution: For the safest handling on the road, the more heavily loaded semi-trailer should be in first position behind the tractor.