CDL General Knowledge practice quiz

Question 1

What should you do first when you notice your vehicle starting to skid on a wet road?

Accepted Answer

Take your foot off the accelerator

Answer

Turn the steering wheel sharply in the opposite direction of the skid

Answer

Apply the brakes firmly to stop the skid as quickly as possible

Answer

Downshift to a lower gear to slow the vehicle with the engine

Question 2

What does the air compressor do in a CMV air brake system?

Accepted Answer

Builds and maintains air pressure in the system

Answer

Supplies air to the brake chambers when the brake pedal is pressed

Answer

Converts air pressure to mechanical force

Answer

Filters moisture from the air lines

Question 3

When must a truck driver recheck cargo securement during a trip?

Accepted Answer

Every 3 hours or 150 miles, whichever comes first

Answer

Only at the destination, once the vehicle has been unloaded and inspected

Answer

Every time the engine is turned off

Answer

Once after the first 100 miles

Question 4

What is the minimum air pressure at which the low air pressure warning device must activate?

Accepted Answer

50 psi

Answer

45 psi

Answer

55 psi

Answer

60 psi

Question 5

What is the purpose of the emergency brake valve on a tractor-trailer?

Accepted Answer

To apply all spring brakes in an emergency

Answer

To provide parking brake function

Answer

To apply only the trailer brakes

Answer

To reduce air pressure for a controlled stop

Question 6

After a minor collision with no injuries, what should a CMV driver do first?

Accepted Answer

Move the vehicle out of traffic if possible

Answer

Call the police immediately and wait for them to arrive at the scene

Answer

Exchange information with the other driver before moving the vehicle

Answer

Wait for a supervisor to arrive

Question 7

How close to the tracks should a bus transporting passengers stop at a railroad crossing?

Accepted Answer

Within 50 feet but not closer than 15 feet

Answer

As close to the tracks as safely possible

Answer

At least 20 feet from the nearest rail

Answer

Exactly at the stop line, regardless of distance

Question 8

Under federal regulations, a CDL driver may not operate a CMV within how many hours after drinking alcohol?

Accepted Answer

4 hours

Answer

2 hours

Answer

6 hours

Answer

8 hours

Question 9

When driving in fog, what lights should you use?

Accepted Answer

Low beams or fog lights only

Answer

Emergency flashers and high beams

Answer

High beams to cut through the fog

Answer

No lights, since they reflect back

Question 10

What color is the air line connected to the emergency (spring) brake relay valve?

Accepted Answer

Red

Answer

Blue

Answer

Green

Answer

Yellow

Question 11

You are approaching a railroad crossing and the gates are starting to come down. What should you do?

Accepted Answer

Stop before the gates and wait until they rise

Answer

Pull around the gate on the shoulder

Answer

Speed up to cross before the gates fully lower

Answer

Stop, then proceed slowly once you can see the tracks

Question 12

The low air pressure warning comes on while you are driving. What should you do?

Accepted Answer

Stop and safely park as soon as possible

Answer

Keep driving and pump the brake pedal to build pressure back up

Answer

Drive on to the next service area before stopping

Answer

Push the parking brake knob in to save the remaining air

Question 13

A CMV's stopping distance is affected by four main factors. Which of the following is NOT one of them?

Accepted Answer

Tire tread depth

Answer

Brake adjustment

Answer

Total vehicle weight

Answer

Road surface conditions

Question 14

What is the maximum number of tiedowns required to secure a 10-foot-long piece of cargo weighing 500 pounds?

Accepted Answer

Two

Answer

One

Answer

Four

Answer

Three

Question 15

During a pre-trip inspection, which of the following items should you check on the steering system?

Accepted Answer

Fluid level, play, and mounting bolts

Answer

The brake pedal return spring, the clutch linkage and the throttle cable

Answer

The gear selector linkage, the shift lever boot and the mounting plate

Answer

Only the power steering pump belt and the color of the steering fluid

Question 16

What is the "four-second rule" used for in CMV driving?

Accepted Answer

Measuring proper following distance behind another vehicle

Answer

Ensuring you check your mirrors at least every four seconds

Answer

Determining how long your turn signal should flash before a lane change

Answer

Timing how long you can run the engine without taking a break

Question 17

What is the purpose of the tractor protection system on a tractor-trailer?

Accepted Answer

To automatically apply trailer brakes if air supply is lost

Answer

To disconnect the trailer during a jackknife to prevent a rollover

Answer

To protect the engine from overheating when it is under a heavy load

Answer

To limit the speed of the trailer on downhill grades

Question 18

When you use the trailer hand valve, what happens?

Accepted Answer

It applies the trailer service brakes only

Answer

It cuts the engine fuel supply

Answer

It engages the tractor parking brake

Answer

It applies the tractor service brakes only

Question 19

What should you check when inspecting the coupling devices during a pre-trip?

Accepted Answer

Kingpin, locking mechanism,Mounting bolts, and apron

Answer

The trailer door hinges, latches and the rear bumper brackets

Answer

Just the fifth wheel lubrication and the grease fittings

Answer

Only the kingpin lock jaw, since it holds the trailer to the tractor

Question 20

When must a CMV driver file an accident report with FMCSA?

Accepted Answer

Only if the accident results in a fatality, injury requiring medical treatment, or a vehicle tow

Answer

Only if the police are called to the scene, write a report, and give the driver a copy of that report within twenty-four hours

Answer

Only if the damage to the vehicles is more than $1,000 in repairs and the carrier has been notified by phone within the same hour

Answer

After every accident of any kind, including minor ones where no one is hurt and no vehicle is towed away from the scene of the crash