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TFH CDL study > General Knowledge > Flashcards

General Knowledge Flashcards

1
Q

The distance you should look ahead while driving is ________ of a mile at highway speed

A

12-15 seconds, 1/4, QRT

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2
Q

What is not the proper time to apply the parking brake?

A

If the brakes are hot

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3
Q

In air brake vehicles the parking brake should be used?

A

Anytime you are parked.

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4
Q

What is counter steering?

A

Turning the wheel back in the opposite direction after steering to avoid an emergency.

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5
Q

Snow packed road. Reduce speed by at least what?

A

1/2

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6
Q

What can brake fade be caused by?

A

Brakes getting hot

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7
Q

Airlines are often colored. The emergency line is? _____

The service line is?_____

A

emergency: RED
service: BLUE

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8
Q

If your ABS is not working on your trailer you should?

A

Drive normally but get the system serviced

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9
Q

What is the distance you should look ahead while driving at low speed?

A

1 block

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10
Q

If you must make an emergency stop you should brake so you…

A

Can keep vehicle in a straight line and turn if it is necessary

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11
Q

You should supply air to the trailer tanks by…

A

Pushing in the trailer air valve

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12
Q

For air brake systems in good condition the air compressor should start pumping at what PSI?

A

100

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13
Q

Total stopping distance for air brakes is longer than hydraulics because?

A

Brake lag

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14
Q

Your emergency line breaks if gets pulled apart while driving. The loss of pressure will cause the _______________.

A

emergency trailer brakes to come on

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15
Q

All air brake equipped vehicles must have what?

A

A supply pressure gauge.

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16
Q

What actions are NOT recommended for a Left turn?

A

When you start in the inside lane and you swing right as you turn.

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17
Q

Emergency Controlled Braking is…

A

When you apply the brakes as hard as you can w/o locking the brakes.

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18
Q

A slack adjuster probably needs adjustment if it moves more than _______ when you pull on it.

A

1 inch

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19
Q

What gear should the trans be in after you have uncoupled and are inspecting the trailer?

A

Neutral

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20
Q

The hand valve should be used…

A

To test the trailer brakes

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21
Q

You must park on the side of a level. Straight two lane road where should you place your triangles?

A

10 ft , 100 ft , 100 ft

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22
Q

You have pushed in the trailer air supply valve. You should not move the vehicle until the whole system is…

A

Normal pressure

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23
Q

The driver must be able to see a low air pressure that must come on before the pressure in the tanks falls below what? ________

A

60 psi

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24
Q

Air compressor should stop pumping at what PSI?

A

125 PSI

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25
Q

How do you test the air service brakes?

A

Brake firmly while slowly moving forward.

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26
Q

If you cannot make a right turn w/o swinging into another lane you should?

A

Turn wide as you complete the turn

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27
Q

Before you back under a trailer make sure of what?

A

The trailer brakes are locked.

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28
Q

If your truck or bus has a dual parking control valve you can use the pressure from another tank to __________________.

A

Release the spring brakes to move the vehicle in an emergency.

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29
Q

Where should the tractor be when you inspect landing gear after uncoupling the trailer?

A

With the tractor frame under the trailer.

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30
Q

Safest way to make a turn when entering another traffic lane is…

A

When you turn side as you complete the turn.

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31
Q

The trailer air supply valve should automatically close when air pressure falls to what range?

A

20-45 PSI

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32
Q

You have coupled to a trailer. Where should the landing gear be before driven away?

A

Fully raised with the Crank Handle secure.

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33
Q

Retarders can be used when?

A

Only where permitted by law

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34
Q

When driving in cold weather your tire depth should?

A

Provide enough traction to steer and get through the snow.

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35
Q

What should you do if you see a hazard in the road way ahead of you?

A

Use your 4-way flashers or brakes lights to warn others.

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36
Q

What does emergency braking mean?

A

Responding to a hazard by slowing the vehicle.

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37
Q

Loss of air pressure in the emergency line __________

A

Causes the trailers emergency brakes to come on

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38
Q

If a straight truck goes into a front wheel skid it will?

A

Go straight ahead even if the wheels are turned.

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39
Q

Trailer is most likely to Jack Knife when it’s ______.

A

Empty

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40
Q

The tractor protection valve will close and the trailer emergency brakes will come on when there is a major leak in what airline?

A

Emergency

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41
Q

Which of these lights cannot be checked at the same times?

A

Turn signals, brake lights, 4-ways

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42
Q

The higher your center of gravity of your truck the _____________.

A

easier it is to turn over.

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43
Q

The modulating control valve allows you to control the ________.

A

Spring brakes

44
Q

Most common type of foundation brake found in heavy vehicles is the?

A

S-Cam brake

45
Q

Stab braking

A
  • involves releasing the brakes only after the wheels lock up
  • Help to keep the vehicle from skidding
46
Q

Off tracking or cheating causes which of these to follow the widest path while making a turn,

A

3 axle tractor towing a 45ft trailer.

47
Q

After connecting the airlines but before backing under the trailer you should _____________.

A

Supply air to the trailer then pull out the trailer air supply valve.

48
Q

After you have coupled to a trailer the tractor protection valve should be in the _______ position.

A

Normal

49
Q

What activates the stop switch?

A

Air pressure

50
Q

Where should you place warning devices if you must stop on a one-way divided highway?

A

10, 100 and 200 feet

51
Q

How many tie downs should a cargo be held with?

A

Minimum of 2

52
Q

Which of these are not a danger of rough acceleration?

(A) Tire Damage
(B) Mechanical Damage
(C) Damage to Coupling

A

(A) Tire Damage

53
Q

Backing a commercial vehicle is:

A

Always dangerous

54
Q

After starting the engine coolant temp. should ______________.

A

Begin a gradual rise to the normal range

55
Q

Whenever you double your speed, how much more distance does it take to stop?

A

4 times

56
Q

What is the bridge formula?

A

Permit less maximum axle weight for axles that are closer together.

57
Q

What statement is true about downshifting in a curve?

A

To downshift for a curve, you should do so before you enter the curve.

58
Q

What 3 things add up to the total stopping distance?

A

(1) Perception Distance
(2) Reaction Distance
(3) Braking Distance

59
Q

Perception distance is the distance your vehicle travels from the time…

A

The eyes see a hazard to the time the brain knows it’s a hazard

60
Q

How far ahead of the vehicle should the driver look while driving?

A

12-15 seconds

61
Q

To stop a trailer skid you should?

A

Release the service brakes

62
Q

Air brake equipped trailer made before 1973 often do not have ___________.

A

Spring brakes

63
Q

You are coupling a tractor to a semi-trailer and you have backed up but are not under it. What should you hook up before backing under it?

A

Emergency & Service airlines

64
Q

If your brakes fail on a downgrade you must first:

A

Look outside your vehicle for another means of slowing it.

65
Q

If you must have a heavy load that is slowing you down on an upgrade you should?

A

Shift in a lower gear

66
Q

Emergency stab braking is where you…

A

Brake as hard as you can, release the brakes when the wheels lock and apply the brakes again

67
Q

The total weight of powered unit trailer and cargo is called?

A

Gross Combination Weight

68
Q

Which system should receive extra attention during cold weather?

A

Exhaust

69
Q

Most serious skids result from?

A

Driving too fast for conditions.

70
Q

Hydroplaning is more likely when?

A

Tire pressure is low.

71
Q

What should you do when your vehicle hydroplanes?

A

Release the accelerator.

72
Q

In the event of a rear tire failure, dual rear tire will usually prevent?

A

Fish tailing

73
Q

How do you correct a rear wheel acceleration skid?

A

Stop acceleration

74
Q

How much space should be between the Upper and Lower fifth wheel after coupling?

A

None.

75
Q

To be safe while driving, you should leave at least 1 second for every ___ feet of vehicle length.

A

10

76
Q

When using tie downs, what weight should the tie down be able to lift?

A

One and a half times the weight.

77
Q

When should you use the hand valve to park a combo vehicle?

A

Never.

78
Q

What part of the Kingpin should the Jaws be locked around?

A

Shank.

79
Q

When hydraulic brakes fail while driving. What action do you take?

A

Pump the brake pedal to generate pressure.

80
Q

If your truck has a dual air system and 1 system is low on air pressure then…

A

Either the Front or Rear brakes will not be operating fully.

81
Q

What happens to tar on the road when pavement gets hot?

A

Bleeds. Making the road surface slippery.

82
Q

Proper way to signal lane changes?

A

Signal early, Change lanes slowly & smoothly

83
Q

After you have coupled the trailer you should begin raising the landing gear using what gear?

A

Low

84
Q

You are coupling a tractor to a trailer. The trailer is at the right height when:

A

The trailer is raised slightly when the tractor is backed under it.

85
Q

During normal driving spring brakes are usually held back by:

A

Air pressure

86
Q

What is the average effective braking distance?

A

216 feet

87
Q

How often should you check your mirrors?

A

Every 8-10 seconds

88
Q

When checking that the trailer is securely coupled to the tractor, the landing gear should be:

A

Slightly raised

89
Q

What is true about ABS?

A

It changes the way you brake in an emergency

90
Q

Braking power of the spring brakes:

A

Depends on the brakes being in adjustment

91
Q

If the spring brake is on, when should you push the brake pedal?

A

Never

92
Q

Air brakes take more time to stop than hydraulic brakes because:

A

Air takes more time to flow through the lines than hydraulic fluid.

93
Q

Air loss rate for straight truck w/ engine off and brakes on:

A

3 PSI in 1 min (60 seconds)

94
Q

The safety valve is set automatically to reduce pressure in the tanks at what PSI?

A

150 PSI

95
Q

If the service line comes apart but the emergency line stays together. What will happen right away?

A

Nothing is likely to happen until you apply the brakes.

96
Q

Air leakage rate for combination

A

4 PSI

97
Q

The application pressure gauge shows you how much pressure:

A

You are applying to the brakes

98
Q

Supply pressure gauge shows how much pressure:

A

Is in the air tanks

99
Q

The brake pedal in an air brake system:

A

Controls the air pressure applied to put on the brakes

100
Q

Spring brakes on trucks will bring it to a stop automatically when it falls to what range?

A

20-45 PSI

101
Q

Excessive heat caused by using your brakes too often can cause the:

A

Brakes to fail

102
Q

If truck has ABS it will have a _______ malfunction.

A

Yellow

103
Q

Modulating control valve allows you to operate the:

A

Spring brakes

104
Q

How often should you drain the water from the air tanks?

A

End of the day

105
Q

Modern air brakes combine 3 different systems

A

(1) Service
(2) Parking
(3) Emergency

106
Q

Air brake lag at 55 mph adds how many feet of stopping distance?

A

32 feet

107
Q

Cracks in the drum can not be longer than _____.

A

1/2 inch

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