California CDL: Double & Triple Trailers Practice Test

Not quite. The answer is Use the engine brake or speed retarder.

A retarder supplements the braking force on the drive wheels. On a slippery surface, this may cause the wheels to lock, resulting in a skid. Turn off your retarder when driving on wet, icy, or snowy roads. Instead, slow down, increase your following distance, and try to brake gently.

Not quite. The answer is slow down.

You should always be able to stop within the distance you can see ahead. Your low-beam headlights let you see only about 250 feet ahead. At 55 mph, your vehicle will travel 250 feet in just 3.1 seconds – not enough time to notice and safely avoid a hazard that's within 250 feet of you. At 30 mph, your vehicle will travel 250 feet in 5.7 seconds.

Not quite. The answer is Use wheel chocks.

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. This will set the trailer emergency brakes (assuming the slack adjusters are correctly adjusted). However, if you have any doubt about the effectiveness of the trailer's braking system, chock the wheels.

Not quite. The answer is directly in front of the converter dolly.

Back the first trailer into position in front of the tongue of the dolly. Hook the dolly to the pintle hook on the first trailer. Then latch the pintle hook securely. Raise the dolly's landing gear.

Not quite. The answer is Neither of the above will cause it.

Despite what footnote 5 in 49 CFR 393.11 says, Operational Policy 15 of the North American Standard Out-of-Service Criteria states that a converter dolly must have one stop lamp, one tail lamp, and (if the dolly obscures the tractor's rear turn signals) turn signal lights, but only when the dolly is being towed singly and is not towing a trailer. In a full multi-trailer configuration, the rearmost trailer must have working stop lights and taillights, of course.

Not quite. The answer is drive through quickly.

If you drive through water at higher speeds, your tires may lose their grip of the road and start to skid. When driving through water, slow down and shift into a low gear. Increase engine rpm and apply the brakes gently to keep the brake linings pressed against the brake drums or discs. This will help keep contaminants out of the brakes.

Not quite. The answer is enough to take some of the weight off the dolly.

When uncoupling a loaded second or third semitrailer, lower the landing gear until it makes firm contact with the ground. Then crank the landing gear in low gear for a few more turns – just enough to lift some weight off the dolly, but not so much that you lift the trailer off the fifth wheel. This will make it easier to unlatch the fifth wheel now and couple the trailer next time.

Not quite. The answer is sometimes lack antilock brakes.

All trailers and converter dollies built since March 1, 1998 are required to have antilock brakes (ABS).

Not quite. The answer is 11

The formula for following distance is one second per ten feet of vehicle length, plus an extra second if you are traveling over 40 mph. Therefore, for a 100-foot vehicle traveling at 50 mph, you should leave a following distance of 100/10 + 1 = 11 seconds.

Not quite. The answer is Either (a) or (b)

Federal regulation 49 CFR 380.205 states that you must meet various requirements before you can start training to operate a triple long combination vehicle. These requirements include 6 months' immediately prior experience driving either a tractor/semi-trailer combination or a tractor/semi-trailer/trailer combination, with a gross combination weight rating (GCWR) of at least 26,001 pounds.

Not quite. The answer is Uncouple the third semitrailer from the second dolly.

To couple a triple-trailer combination, you couple the tractor and first semitrailer to the second and third semitrailers. But to uncouple the triple-trailer combination, you start by just uncoupling the third semitrailer from the rest of the combination.

Not quite. The answer is The heaviest trailer

The rearmost trailer is much more likely to roll over than the front trailer. Position the heaviest trailer directly behind the tractor and position the lightest trailer at the rear.

Not quite. The answer is closed; latched

When you do a walk-around inspection, you must ensure that the converter dolly is properly connected to the front trailer. Check that the pintle hook of the front trailer is locked onto the eye hook of the converter dolly and properly latched. Otherwise, the dolly could come loose. Even worse, if the dolly comes loose while it's still coupled to the rear trailer, the tow bar could fly up, possibly injuring someone.

Not quite. The answer is Pull against the rear semitrailer's pin.

To check the coupling of the rear semitrailer, pull against the pin holding the rear semitrailer. Never move your vehicle until you are sure that all trailers are properly coupled.

Not quite. The answer is If there are vehicles on both sides of you, a move to the right may still be best.

To avoid a head-on collision, steer right toward the shoulder or curbline. Even if you are blocked on both sides by other vehicles, a move to the right may still be best. At least you won't force other drivers into an opposing traffic lane, possibly involving them in a head-on collision. Prepare to drive entirely off the roadway to the right if necessary to avoid a head-on collision. Head-on collisions are often fatal.

Not quite. The answer is you couple the third trailer to the second trailer before you couple them to the first trailer.

A triple combination vehicle has four units (not counting the converter dollies): a tractor and three trailers. You couple a triple as follows: 1. Couple the first trailer to the tractor the same way that you couple any combination vehicle. 2. Couple the third trailer to the second trailer using the method for coupling doubles (which will involve the use of a converter dolly). 3. Move another converter dolly into position. 4. Couple the tractor and first trailer to the second and third trailer using the method for coupling doubles (which will involve another converter dolly).

Not quite. The answer is only the more common types of combinations.

The official CDL manual's section on double and triple trailers usually describes how to couple and uncouple the more common types of double and triple combinations. However, there are other ways of coupling and uncoupling the many types of truck-trailer and tractor-trailer combinations that are in use. To learn how to couple and uncouple the vehicles you will be driving, consult the manufacturer's or owner's specifications.

Not quite. The answer is There should be none.

When the rear trailer is properly coupled to the converter dolly, there should be no space between the upper and lower fifth wheel. (Similarly, when the front trailer is properly coupled to the tractor, there should be no space between the upper and lower fifth wheel either.) If there is visible space, something is wrong. Don't drive the vehicle until you have corrected the problem because the trailer might come loose.

Not quite. The answer is less

Double and triple vehicles are more prone to rolling over or jackknifing than single vehicles are. Avoid sudden braking or steering changes. Look far enough ahead that you can slow down or change lanes gradually when necessary.

Not quite. The answer is restore traction to the tires.

If braking or steering force exceeds the tires' traction with the road surface, a skid may result. You can recover from the skid by restoring sufficient traction.