Question 1

The acceptable air pressure loss in a combination vehicle with a fully charged air system is?

Accepted Answer

In a combination vehicle with a fully charged air system the acceptable loss of air pressure is less than 3 psi per minute. This test is performed by turning off the engine and releasing the parking brake, then measuring the loss of air pressure within a one minute period. This test is almost always a part of the CDL exam, and because of its importance should always be conducted during pre-trip inspections on ALL vehicles that utilize air brakes.

Question 2

Class A drivers require more training because combination vehicles are:

Accepted Answer

Class A combination vehicle drivers require more training and care in operation because these types of commercial vehicles pose special risks. More than one-half of all combination truck accidents are due to rolling over. Because of their added length, turning radius, and passing requirements, these big rigs require additional training and skills.

Question 3

To obtain an endorsement for doubles and triples, applicants must show specific knowledge concerning which of the following:

Accepted Answer

In order to obtain an endorsement for doubles and triples, applicants must be able to show that they understand all aspects of these specialized vehicles. Applicants must be able to show that they understand the correct procedures for hooking and unhooking multiple trailers. They must also show that they understand the special handling, steering, braking, and driving characteristics associated with doubles and triples.

Question 4

When connecting doubles, drivers connect the emergency line and charge the trailer air tank. This causes what to happen?

Accepted Answer

When hooking up doubles, drivers must connect the emergency line and fully charge the trailer air tank in order to automatically set the trailer's emergency brakes. In addition, it is wise to set wooden blocks behind the wheels of the last trailer to stop it from possibly rolling. Drivers should always inspect their air line connections before trusting them to hold the brakes. This can prevent serious or fatal injuries.

Question 5

When attaching the converting dolly to the lead trailer through the ring hitch, drivers should:

Accepted Answer

When hooking up the converting dolly to the lead trailer, drivers must connect the air hose to the converter dolly. Not connecting the air hose at this time can lead to dangerous situations that may cause harm to others or damage to the equipment. Drivers must ensure that the ring hitch is secure before connecting the air hose.

Question 6

When connecting doubles or triples, one of the last steps is to check the air pressure for the last trailer's air brakes. You do this by:

Accepted Answer

When connecting doubles or triples, it is imperative that drivers check the air pressure for the last trailer's brakes. Drivers perform this action by pressing the "air supply" button that is found on the rear of the last trailer. There should be air pressure in the system. If not, have the system inspected before moving the trailer. Low or no air pressure will cause the brakes to malfunction.

Question 7

The 45° angle reverse maneuver is often the preferred method for backing into a loading dock or parking space. When performing this action, drivers should:

Accepted Answer

When backing into a loading dock or parking space using the 45° angle reverse method, drivers should angle their trailers toward the driver's side at a 45° angle. To better see the left side of the trailer, drivers may want to angle their tractor a bit more than their trailers. These actions allow drivers to rely on their driver's side, left hand mirrors as they back into their spaces.

Question 8

When hooking up air supply lines between tractor and trailer, the air lines:

Accepted Answer

When hooking up the air supply lines between the tractor and trailer, the air lines must match according to color. The red air hose must connect with the red gladhand and the blue air hose must connect with the blue gladhand. Mismatched air lines and gladhands will prevent the air brakes from functioning. Drivers must ensure that all connections are securely made before moving the vehicle.

Question 9

When inspecting gladhands, drivers should look for which of the following defects:

Accepted Answer

Driver must inspect the gladhands before they make their air hose connections. Things to look for include missing grommets (which should be inside the gladhand), cracked grommets, and gladhands that may have been damaged. If any of these conditions exist, drivers must have the problem fixed before moving the vehicle. Failure to do so may result in loss of braking ability once on the road.

Question 10

Once the tractor and trailer have been connected, the driver should immediately perform which of the following?

Accepted Answer

Once the tractor and trailer have been attached and all air lines connected, drivers must perform a pull test. In a pull test, the brakes are engaged by pulling out the red brake knob, shifting into first gear, and gently easing the tractor forward. If all is correct, the trailer should hold back the tractor. If drivers notice that the trailer moves forward during the pull test, they should immediately have the trailer brakes inspected and serviced.

Question 11

If drivers notice that the trailer front edge is too low for their tractor's fifth wheel to slide under, they should:

Accepted Answer

Before actually sliding the tractor's fifth wheel under the trailer, drivers should always make a visual inspection to see if the trailer is high enough. If the trailer's front edge is too low, the driver should drain some air from the tractor's air ride bags. This will lower the back end of the tractor enough that it can be slipped under the trailer safely. The driver should then re-inspect to make sure that the tractor fifth-wheel is lower than the fifth-wheel plate on the underside of the trailer.

Question 12

The control switch for adding or removing air from the air ride bags is located:

Accepted Answer

The control switch that is used to fill or drain air from the air ride bags is located inside the tractor cab. Using this switch, drivers can raise or lower the rear end of their tractors to fit under trailers. It is important that drivers always check to see if their fifth wheel will slide safely under the trailer before they attempt to back under the trailer. Failure to do so can result in damaged tractors and trailers.

Question 13

Which of the following statements is true about longer vehicles, such as those with sleeper compartments?

Accepted Answer

Drivers of long wheelbase tractor trailers must always be aware that these vehicles require more room when making a right turn. It is essential that drivers who are accustomed to operating short wheelbase tractor trailers get some practice turning both directions before operating a long wheelbase rig on public roads. The major causes of right hand turn accidents in tractor trailers are drivers did not swing out far enough or drivers that swung out too far. There is little room for error when making right hand turns.

Question 14

When pulling doubles or triples, which trailer is more likely to roll over?

Accepted Answer

When pulling doubles or triples, drivers must be aware of the added danger of the last trailer rolling over. While it is true that pulling doubles or triples always comes with the added risk of a rollover, the last trailer in line is often the one that will roll first. To prevent a rollover, steer gently and slow down on curves and turns. Understand that the posted speed limit may be too fast for vehicles pulling doubles and triples. Slow down!

Question 15

When making a left turn in a combination vehicle, you should:

Accepted Answer

When making a left turn, combination vehicle drivers and long wheelbase vehicles such as buses should make sure that they have reached the center of the intersection before they begin turning the steering wheel. Turning too soon can result in your vehicle hitting something or someone on your left side due to off-tracking. It is important that Class A drivers understand the principles behind off-tracking for both right and left hand turns.

Quiz 4: Class A