iowa
CDL Practice Test

Below are practice questions for the Iowa CDL test. The site is free and you are able to take the practice test as many times as you need to as you prepare to obtain your Iowa CDL. The questions and answers covered in these Iowa practice CDL tests are taken from the Iowa DOT CDL manual. You will be presented with 40 questions and you must answer 34 questions correctly to pass. There is a 50-minute time limit. You may not go back once you answer a question. Click the "Start Test
" button below to begin.

1 / 40

To transport cargo safely, which of these are you NOT responsible for?

recognizing possible overloads

inspecting the cargo

making sure that cargo is properly secured

ensuring the freshness of sealed cargo

2 / 40

While driving on a clear night with low beam headlights, you should be able to stop within:

Half of a football field.

The distance you will travel in the next 20 seconds.

2 lengths of your vehicle.

The distance you can see ahead of you.

3 / 40

_____ create a little above 90 degree angle between the adjuster arm and push rod when the brakes are released and no less than 90 degrees when the brakes are applied.

air lines

slack adjusters

brake drums

brake disc

4 / 40

How often should you check the tires on a placarded trailer that has dual tires?

Start of each day and every time you stop.

Once every three hours.

Each time you stop.

Once every 100 miles.

5 / 40

What is the movement of the liquid called when the tanks are partially filled?

Knocking

Surging

Framing

Crashing

6 / 40

Is this statement true or false: You do not need to use the parking brake if are leaving your vehicle for a short amount of time.

false

only when the vehicle has over 60,000 miles on it

only when the vehicle has over 25,000 miles on it

true

7 / 40

What is the purpose of the supply pressure gauge?

all of these answers are correct

to inform you of how much air is in the tank

to inform you about how hot the air in the tank is

to inform you if there is too little air in the tank

8 / 40

You must keep shipping papers describing hazardous materials ______.

within 100 feet of the hazardous materials at all times

in a pouch on the driver’s door or in clear view within immediate reach while the seat belt is fastened while driving on the driver’s seat when out of the vehicle

in a pouch on the drivers door or in the overhead compartment above the driver’s seat only

with the bills of lading

9 / 40

Select the portion of the combination vehicle that is most likely to turn over suddenly when pulling a double trailer:

all are equally likely

the front trailer

the tractor

the back trailer

10 / 40

Under which two special conditions should you downshift?

before starting down a hill and before going up a hill

before entering a curve and before going up a hill

before starting down a hill and before entering a curve

if there is an accident and in sudden heavy rain

11 / 40

What is the purpose of a baffle?

It controls the surge of liquid forward and backwards.

It makes it easier to clean the tanker out.

It allows you to haul loads that are mixed.

It stops side to side surging.

12 / 40

Your bus is disabled. With riders aboard, the bus may be towed or pushed to a safe place only:

By a 27,000 lbs gvwr or larger tow truck.

If getting off the bus would be more risky for the riders.

If the distance is less than 500 yards.

By another bus with its four-way flashers on.

13 / 40

Upon what does the amount of liquid you can carry in a load depend?

The amount of expansion that will occur.

All of the answers listed.

The legal weight limits.

The weight of it.

14 / 40

Always try to back toward the driver's side because

your truck will naturally pull toward the driver's side

it's more comfortable for turning your neck

you can see better, watching the vehicle rear out the side window

all of these answers are correct

15 / 40

At a railroad crossing, the bus is required to stop at the stop line. If there is no clearly marked stop line, what is the required minimum and maximum stopping distance?

No closer than 10 feet and no further than 60 feet, where you have the best view of the tracks.

No closer than 15 feet and no further than 50 feet, where you have the best view of the tracks.

No closer than 10 feet and no further than 40 feet, where you have the best view of the tracks.

No closer than 15 feet and no further than 30 feet, where you have the best view of the tracks.

16 / 40

Which of the following is NOT an acceptable type of marking for hazardous materials?

Un marks

Descriptive name in roman print

Name in italics

Identification number

17 / 40

What is the purpose of cladding in a tanker?

It eliminates liquid surge.

It protects the tanker form any corrosive cargo.

It controls the temperature of the cargo.

It protects the cargo from changes in temperature.

18 / 40

When stopped on a divided highway where should your reflectors be placed?

15 feet, 75 feet, and 150 feet toward the approaching traffic

10 feet, 100 feet, and 200 feet toward the approaching traffic

20 feet, 150 feet, and 300 feet toward the approaching traffic

30 feet, 100 feet, and 150 feet toward the approaching traffic

19 / 40

A tank vehicle:

Is a vehicle that can transport bulk fertilizer.

Is a vehicle that can transport liquid.

All answers listed.

Is a vehicle that can transport liquified gasses.

20 / 40

When would you lock some emergency roof hatches in a partly open position?

Never

Whenever you enter a tunnel

For fresh air

First day of spring

21 / 40

Select the true statement about what the Air Compressor Governor controls:

it controls when the air compressor pumps air into the storage tanks

it controls when air is released from the storage tank

it controls when the brakes will be applied

it controls when the warning system is activated

22 / 40

Tankers used to transport hazardous materials on vehicles must be marked with:

The owner's puco or icc number.

The date of manufacture.

The un or na id number of the product.

The chemtrec phone number.

23 / 40

Do empty trucks have the best braking?

yes, but only if the truck is newer than 1998

yes, but only on wet surfaces

yes

24 / 40

Which trailer is more likely to roll over when pulling 3 trailers?

the first trailer

the tractor

the second trailer

the last trailer

25 / 40

Of the following hazardous material classes, which is the most dangerous?

Division 64

Division 62

Division 61

Division 63

26 / 40

What should you do if the low air pressure warning comes on for only one system in a truck or bus that has a dual air brake system?

decrease your speed and test the other system

continue on with your trip

decrease your speed and head to the closest mechanic

stop and safely park your vehicle only continue once the issue has been resolved

27 / 40

You are driving a 60 foot truck at 55 MPH, how much space (in seconds) should you keep in front of you?

6 seconds

7 seconds

8 seconds

5 seconds

28 / 40

Which of the following statements is FALSE?

you can almost always turn to miss an obstacle more quickly than you can stop

anti-lock braking systems (ABS) only activate when wheels are about to lock

if a tire blows, you should put the brakes on hard to stop quickly

stopping is not always the safest thing to do in an emergency

29 / 40

If you are hauling hazardous materials and have ___ tires on your vehicle, you must stop and check them every time you park.

dual

bias

radial

treaded

30 / 40

Which of the following is the proper definition of a cargo tank?

A bulk container permanently attached to a vehicle.

None of these answers are correct.

A bulk container not permanently attached to a vehicle.

A bulk container which can be securely affixed to a vehicle.

31 / 40

The floor liner for explosives may not:

Contain nails or screws.

Contain cracks or holes.

Contain steel or iron.

Contain any of these materials.

32 / 40

What is the purpose of a driver placarding his or her vehicle?

Giving people something interesting to look at while driving.

Forcing other drivers to stay 20 feet away in every direction.

Communicating risk.

Warning those with children to drive in another lane.

33 / 40

Select the inappropriate way to test for the low pressure warning signal.

ask for a pedestrian to listen for the signal

decreased the air pressure by stepping on and off the brake pedal

have the electrical power on

turn off the engine

34 / 40

In what position should the shut off valves on a the rear of the front trailer be in on a set of double trailers?

in a closed position

in a halfway open position

in a 1/3 way open position

in an open position

35 / 40

Select the statement that is true in regards to quick steering movements and triple/double trailers:

it is easier to countersteer compared to other vehicles

as you perform quick steering movements you should apply pressure to the brake pedal

they flip over due to quick steering movements a lot easier than other vehicles

there are no issues that occur from quick steering

36 / 40

What position should the heaviest trailer be in when pulling 3 trailers?

in the front

it makes no difference

in the middle

in the back

37 / 40

Check to ensure that____when inspecting the coupling.

there is no slack at all in the air lines

there is minimal slack in the air lines

the landing gear handle is free to hang down

the electrical cable is unplugged

38 / 40

What are the three types of emergency equipment that you must have with your vehicle?

none of these answers are correct

first aid kit, fire extinguisher, flares

fire extinguisher, spare electrical fuses, warning devices for parked vehicles

warning devices for parked vehicles, first aid kit, flares

39 / 40

Your vehicle is going down a long hill and your brakes begin to fail. What should you do?

look for an escape ramp or an escape route

pump the brake pedal

downshift

put the gears in neutral

40 / 40

Select the true statement in regards to if a glad hand on the blue air line is missing a seal.

you should remove one from the red air line to use as a temporary replacement

there may be a service line air leak

it is not a big problem

there may be an emergency line air leak

Your score is

The average score is 0%

5/5 - (1 vote)

CDL Category Practice Tests

CDL Practice Test

How To Get An iowa Commercial Drivers License

Individuals may apply for their CDL starting at age 18. To be eligible for interstate driving as well as HazMat and Doubles/Triples applicants must be 21 years of age or older. All individuals applying for an Iown CDL must present a Medical Examiner’s Certificate according to the United States Federal Regulations.

If any one of the descriptions below is true about an applicant, they will be disqualified from receiving their CDL.

Driver posses more than one driver’s license.
Driver was convicted of driving under the influence in the past 24 months.
Driver has a suspended, denied, canceled, or revoked driver’s license.

Endorsements
H – Hazardous Materials
N – Tank Vehicle
T – Doubles/Triples
X – Hazmat and Tank Comb
P – Passenger Vehicle
S – School Bus

Drivers must take a knowledge test as well as a practical skills test to showcase their knowledge of commercial driving laws and their ability to operate a commercial vehicle.

Hit the Open Road

iowa CDL License Test Tips

Applicants must complete a general knowledge test to display their understanding of commercial driving laws. The general knowledge exam is comprised of 50 questions. Those seeking a Class A CDL will need to complete an additional 20 question test on combination vehicles. Applicants seeking additional endorsements will need to take an additional test on the endorsement topic. The Passenger, Tank, and Doubles/Triples Endorsements are 20 question tests. Removing the Air Brake Restriction, the Iowa Operator and School Bus Endorsements are 25 questions. The Hazmat Endorsement is a 30 question test. All applicants must pass the respective assessments with a score of 80 percent or better to receive their Iowa CDL permit.

A skills assessment is required of all applicants. This assessment is comprised of three parts, which are the pre-trip inspection, basic controls skills, and on-road driving. Individuals applying for their P and S endorsements will be required to take the skills test in the respective vehicle for their endorsement.

Additional Information

Information on the Iowa Department of Transportation

The Iowa Department of Transportation administers CDL requirements and testing in Iowa. To get more information contact them via:

Website: https://iowadot.gov/DriversVehicles#CommercialDrivers

Phone: 515.239.1101

Additional Iowa CDL Helpful Links

Please use the links below to access more valuable Iowa CDL testing resources and to learn more about practice driving tests for the state of Iowa.

iowa CDL Practice Test