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1.
Which statement is correct?
a. Doubles and triples require the same level of care as driving
a straight truck
b. Doubles and triples are less stable than other commercial vehicles
c. Doubles and triples are actually safer to operate than other
commercial vehicles
d. None of the above
2.
What is rearward amplification?
a. Increased cab noise from the volume of air passing around the
double and triple trailers
b. Increased tendency of weight shift from the front to the rear
trailer
c. "Crack the whip" effect when turning doubles or triples
d. The weight transfer to the rear axles when there is rapid acceleration
3.
When is the chance of skid and loss of traction the greatest?
a. When driving down a hill
b. When driving up a hill
c. When driving doubles or triples
d. At night
4.
Where is the heaviest trailer position in a set of triples?
a. First trailer position (coupled to the tractor)
b. Second trailer position
c. Third trailer position
d. Either first or third trailer position
5.
Why shouldn't you disconnect the pintle hook with the dolly still
under the trailer?
a. It is a violation of the Federal Motor Carrier Safety Regulations
b. The air lines will disconnect and the emergency brake will
activate
c. The tow bar may fly up, possibly injuring you
d. The pintle lock mechanism may be damaged
6.
When coupling the converter dolly to the first trailer in a set,
what do you do first?
a. Lock the pintle hook
b. Back the trailer in front of the dolly
c. Secure the mud flaps
d. Secure the dolly support valve in the upright position
7.
How should you set the brakes on the 2nd or 3rd trailer you are
coupling if they don't have spring brakes?
a. Connect the service air line to the trailer and have a helper
press down on the brake pedal while you connect the trailer
b. Position the tractor close to the trailer, connect the air
line to charge the trailer air tank and disconnect the emergency
line
c. Connect the air lines from a spare tractor to the trailer and
have the driver of that tractor push down on the brake pedal
d. Adjust the slack adjusters so that they move the brake shoes
in contact with the brake drums on the trailer
8.
When you push in the red "trailer air supply" knob, you will:
a. Supply air to the compressor module
b. Supply air to the emergency line
c. Supply air to the dual reservoir
d. Set the emergency brake
9.
How do you inspect to insure that you have airflow to all trailers
for the emergency air brake system in a set of doubles or triples?
a. Activate the emergency brake system and press on the brake
pedal. If there is more than a 10 psi reduction in the air pressure
storage you have airflow to all trailers.
b. Add one pint of water to the air system, charge the emergency
system, open the air valve at the rear of the last trailer and
if water comes out, you have airflow to all trailers.
c. Activate the emergency air brake system and apply the trailer
hand brake, open the emergency line shut-off valve at the rear
of the last trailer and listen for air escaping. If you can hear
air escaping, you have airflow in the emergency brake system.
d. The only way to test the system is to move the trailers and
apply the brakes.
10.
What are trailer shut-off valves used for?
a. To connect the air line between trailers and converter dollies
b. To close the air lines of the last trailer in doubles or triples
so that air does not leak out of the system
c. To drain the air systems
d. To be used only in emergency for panic stops
11.
When doing a pre-trip inspection on a set of doubles or triples,
what additional inspection should you do that you don't do for
a single-trailer combination vehicle?
a. Check the air pressure at each connection to the trailers
b. Insure that the air flows through all brake systems to all
trailers
c. Check the slack adjusters
d. Check all tires for wear and air pressure
12.
What position should the shut-off valves be in on the last trailer
of a doubles or triples set?
a. Fully closed
b. Fully open
c. 20-45% open
d. Open on doubles, closed on triples
13.
What position should the shut-off valves be in for the first trailer
in a set of doubles?
a. Fully closed
b. Fully open
c. 1/3 turn open
d. Closed unless the vehicle is equipped with automatic slack
adjusters
14.
The converter dolly air drain valve should be in what position
when you inspect doubles and triples during the pre-trip inspection?
a. Fully closed
b. Fully open
c. 20-45% open
d. Open in cold weather; closed in warm weather
15.
What is the rearward amplification of a set of triples compared
to a 5 axle semi trailer with a 45-foot trailer?
a. 2.0
b. 1.0
c. 3.0
d. 3.5
16.
When driving doubles or triples, you should:
a. Do nothing special
b. Decrease air pressure in tires of last trailer
c. Increase following distance
d. Drive in left lane whenever possible
17.
How much space should there be between the upper and lower parts
of the fifth wheel on the dolly when coupled to a trailer?
a. 1/2 inch
b. 1 or 2 inches
c. Less than one inch
d. There should be no space
18.
When inspecting the landing gear on doubles and triples, which
of the following should be checked:
a. Gear raised to upper limit
b. Crank handle in place and secured
c. If power operated, no leaks
d. All the above
19.
Which statement is correct?
a. Doubles and triples need more room to stop because they can't
be stopped suddenly
b. Doubles and triples can be stopped in less room than any other
combination
c. Doubles and triples can only be operated in daylight hours
d. Doubles and triples can negotiate curves at faster speeds than
single trailer combinations
20.
When coupling, you must check the connection for security by:
a. Pulling the tractor gently forward while the trailer brakes
are locked
b. Rocking back and forth
c. Stopping and starting suddenly after achieving 20 mph
d. Backing up at 15 mph and stopping suddenly
Safety & Compliance > CDL
"Double and Triple Trailer" Practice Test