Kentucky CDL: Double & Triple Trailers Practice Test

Not quite. The answer is leaks of air or hydraulic fluid

Check the landing gear as part of your walk-around inspection. Check that no parts are missing and it isn't bent or damaged. If the landing gear is power operated, check its hoses, fittings, and other parts for signs or sounds of escaping air or hydraulic fluid.

Not quite. The answer is Rocky Mountain double

A double pup trailer consists of two 28.5-foot trailers, known as "pup trailers." A double pup trailer is also known as an STAA trailer, named for the Surface Transportation Assistance Act (STAA). This standard-double configuration is the only type of double trailer that is allowed nationwide. A Rocky Mountain double trailer consists of a 40- to 53-foot trailer followed by a 28.5-foot pup trailer. Rocky Mountain doubles are allowed in certain Western states. A turnpike double trailer consists of two 48-foot trailers. Turnpike doubles can be found traveling on expressways in the Eastern states.

Not quite. The answer is Open at the rear of the front trailers and closed at the rear of the last trailer

Air must travel through the air lines of the tractor and all trailers – and that's all. Open the shut-off valves at the rear of each trailer but the last one to enable the air to flow to the trailer behind it. Close the shut-off valves at the rear of the last trailer to keep air from escaping.

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 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 more likely to turn over.

In a double or triple combination, each trailer is more likely to roll over than the one in front of it. The rear trailer of a triple is 3.5 times as likely to roll over as a five-axle tractor-trailer. This is known as the "crack-the-whip" effect, caused by rearward amplification. For safety, position the heaviest trailer in front and the lightest trailer in the rear.

Not quite. The answer is the vehicle is more likely to roll over or jackknife.

A double or triple combination vehicle is more likely to roll over or jackknife from 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 pull against the pin of the second trailer.

Test the coupling by pulling against the pin of the second semitrailer.

Not quite. The answer is Check your mirrors to keep an eye on your tires.

Use the mirrors to keep an eye on your tires. It's one way to spot a tire fire. But your mirrors don't eliminate all blind spots. Your truck still has large blind spots, often called No-Zones.

Not quite. The answer is make things look smaller and farther away than they really are.

A convex mirror has a wider field of view than a flat mirror. However, objects viewed in a convex mirror look smaller and farther away. Remember this when you're trying to judge the distance of an object that you're viewing in a convex mirror.

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 the trailer will be raised slightly when the converter dolly is backed under it.

To connect the rear trailer to the converter dolly, the trailer must be at the right height. It should be slightly lower than the center of the dolly's fifth wheel so that the trailer will be raised slightly when the dolly is pushed underneath it.

Not quite. The answer is latched.

When coupling a converter dolly to the trailer in front of it, place the dolly's pintle eye on the trailer's pintle hook. Latch the pintle hook closed. Secure the dolly's safety chains to the trailer.

Not quite. The answer is Turnpike double trailer

A double pup trailer consists of two 28.5-foot trailers, known as "pup trailers." A double pup trailer is also known as an STAA trailer, named for the Surface Transportation Assistance Act (STAA). This is the only type of double trailer that is allowed nationwide. A Rocky Mountain double trailer consists of a 40- to 53-foot trailer followed by a 28.5-foot pup trailer. Rocky Mountain doubles are allowed in certain Western states. A turnpike double trailer consists of two 48-foot trailers. Turnpike doubles can be found traveling on expressways in the Eastern states.

Not quite. The answer is apply light pressure on the brakes.

Avoid driving through deep puddles or flowing water if possible. If not, slow down and downshift into a low gear. Gently press on the brakes and maintain pressure for a short distance when you are out of the water. This will heat up the brakes and dry them out. (However, don't overdo it, or the brakes may overheat.) Then apply the brakes to make a test stop when it is safe to do so.

Not quite. The answer is do both of the above.

In bad weather or mountain driving or on slippery roads, use extreme caution. When you drive a double or triple, you're pulling a lot of dead axles with just a few drive axles. This increases the chance of loss of traction, causing a skid. Also, rearward amplification makes the rearmost trailer much more prone to rolling over. Drive slowly around curves and turns and avoid sudden moves.

Not quite. The answer is A sudden movement with the steering wheel can result in a tipped-over rear trailer.

Because of rearward amplification (the "crack-the-whip" effect), the rearmost trailer is much more prone to rolling over. Avoid sudden steering changes that could cause the rearmost trailer to roll over.

Not quite. The answer is 3

In this context, articulation or pivoting means movement between two units separated by a joint, such as between a tractor and a trailer. The standard or STAA double combination in the CDL handbook has 3 points of articulation: (1) the fifth wheel of the tractor; (2) the pintle hook of the front trailer; (3) the fifth wheel of the converter dolly.

Not quite. The answer is You need about four times as much braking distance at 40 mph as at 20 mph.

Your total stopping distance is the sum of your perception distance (how far your vehicle goes from when you see the hazard until your brain processes it), reaction distance (how far the vehicle goes from when your brain orders your foot to take action until your foot actually starts to brake), and braking distance (how far the vehicle continues to travel once you apply the brake). Your vehicle's braking distance increases as the square of your speed. For example, you need about four times as much braking distance at 40 mph as you do at 20 mph.

Not quite. The answer is enough to remove some of the trailer's weight from the converter dolly.

Lower the landing gear of the second semitrailer enough to remove some of the trailer's weight from the converter dolly. This will make it easier to pull the dolly out from under the trailer.