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

For what reason do you keep the starter switch key in your pocket during the pre-trip inspection?

so no one moves the vehicle while you are inspecting underneath it

so you don't lose it

you will need it to inspect the trailer

you will need it to open the side box

2 / 40

When does your vehicle's single brake system need an adjustment?

when the governor stops between 75-90 psi

if the compressor cuts out at between 70 and 90 psi

if the pressure builds from 50 to 75 psi in less than 3 minutes

when the pressure builds from 85 to 100 psi in less than 1 minute

3 / 40

Within 3 minutes, this gauge pressure should build to 90 psi from 50 psi.

Oil pressure gauge

Coolant pressure gauge

Air pressure gauge

Voltmeter gauge

4 / 40

You must first______to supply air to the trailer.

turn off the engine so you can hear the brakes

pull out the tractor protection valve

cross the air lines to check for the presence of leaks

push in the tractor protection valve

5 / 40

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

Surging

Crashing

Knocking

Framing

6 / 40

How do you make sure the air lines are not crossed and the trailer brakes are working after supplying air to the trailer?

lift the brake pedal up

activate the parking brakes

listen for brake sounds as you apply pressure off and on the trailer brakes

release the tractor brakes

7 / 40

A shipment described on the Hazardous Waste Manifest may only be delivered to another _______ carrier or treatment facility, who then signs the ______, giving you a copy which you must keep.

licensed, manifest

trucking, uniform hazardous waste manifest

registered, uniform hazardous waste manifest

responsible, papers

8 / 40

When driving in very hot temperatures, you should:

check your tires every 2 hours or every 100 miles

let your tires cool down (remain stopped) if they are too hot to touch

insure that you have enough antifreeze in the system

all of these answers are correct

9 / 40

The best way to have control on curves is:

to shift to a lower gear before entering the curve

keep pressure on the brake pedal through the turn

you do not need to do anything different

to decrease to your safe speed before entering the curve and then accelerate through it

10 / 40

What is the purpose of cladding in a tanker?

It protects the tanker form any corrosive cargo.

It protects the cargo from changes in temperature.

It controls the temperature of the cargo.

It eliminates liquid surge.

11 / 40

The system that needs to be checked for signs of leaks with rust or carbon soot and damage is the _____.

none of the answers listed

air brake system

exhaust

fifth wheel

12 / 40

Do you need to stop before a railroad crossing if you are hauling 100 pounds of Division 4.3 Dangerous When Wet material?

Yes

Only in populated areas

Only if you have more than 1,001 pounds of it

13 / 40

Off-tracking happens when going around a corner and:

the front part of the trailer pulls to the right

the rear wheels follow a different pathway than that of the front wheels

the rear wheels follow the front wheels in a straight path

the rear part of the trailer goes into the shoulder

14 / 40

This item should not be rusted, bent, or damaged and centered over evenly spaced tires and dual wheels.

Fifth wheel

Lug bolts

Frame

Spacers

15 / 40

Shifting into a lower gear and removing your foot off of the accelerator to slow your vehicle is known as?

double clutching

engine braking

anti-lock braking

brake fade

16 / 40

Which of the following are possible causes of tire fires?

loose fuel connections or under-inflated tires

dual tires that touch and under-inflated tires

poor cargo ventilation or short circuits

improperly loaded cargo and dual tires that touch

17 / 40

This object is not checked at the rear of the trailer.

The header board

The back doors

The mud flaps

The bumper

18 / 40

There must be a hazardous materials identification number on the ______ and on the ______.

invoice, shipping papers

package, trailer

shipping papers, package

trailer, packages

19 / 40

Select the true statement in regards to crossing your air lines on a new trailer with spring brakes

you will be unable to release the tractor brakes

you will have brakes that are not operational

there is no way to know if there is an issue

you will be unable to realse the trailer brakes

20 / 40

Which of the following is a recommended procedure when unloading the students?

Position yourself outside of the bus in front of crossover mirror to supervise unloading.

Put the transmission in neutral gear and put on the brakes.

Let the students begin moving to the front of the bus before it's fully stopped to maximize efficiency.

Tell students to remain seated until they are told to exit.

21 / 40

What position should the tractor protection control valve be in after coupling?

mid position

lowered

raised

normal

22 / 40

Select the true statement in regards to your brake function when your ABS fails

the abs will need to be repaired but the brakes will function normally

you will need to pull over immediately

you will have no control over your truck as the brakes will not be functioning

there is a huge fire risk

23 / 40

What are spring brakes?

they are large springs that are held closed by air pressure if the air pressure is increased the brakes are applied

they are powerful springs that are restrained by air pressure when the air pressure is removed, the brakes are applied

they are big springs with air pressure in them if the air pressure decreases, the brakes are applied

none of the answers listed

24 / 40

How do you test your service brakes?

apply pressure to the brake pedal when moving at highway speeds

release the air pressure and activate the parking brake

after releasing the parking brake, move forward slowly and apply pressure to the brake pedal

pull over and activate the parking brake

25 / 40

Air tanks need to be drained:

to prevent water and oil from building up in the tank

to keep the tanks warm when not in use

to keep the tanks cold when not in use

air tanks should absolutely never be drained

26 / 40

The compressor is connected to the engine via _____?

v-belt or gears

stag gears

r-belt

lines

27 / 40

What is most likely to occur when driving a set of doubles and a set of trailer wheels goes into a skid?

no matter how you turn the steering wheel, the rig will continue in a straight line

nothing will occur

there will be a trailer jackknife

the rig will slide sideways but stay in a straight line

28 / 40

A driver that hauls hazardous materials must attend training every:

2 years

1 year

3 years

None of these answers are correct

29 / 40

You should keep a minimum of ____between another vehicle and the double trailer with 100 ft truck driving at 30 mph.

13 seconds

15 seconds

10 seconds

8 seconds

30 / 40

The gauge that needs to come up to normal levels after starting the engine within a few seconds is _____.

blood pressure

air brake pressure

oil pressure

oil temperature

31 / 40

Select the factor that is known to cause brakes to fail or fade. (more than one answer may be correct, but select only one)

tire retread that is mismatched

excessive heat from extensive use

when using the engine brake more than the brakes

brakes that are not aligned properly

32 / 40

You must have placards for explosives, poison gas or flammables exceeding:

10 pounds

10 cartons

Any amount

100 pounds

33 / 40

If you have riders on board, you must never refuel:

Unless on a scenic tour bus.

In a closed building.

At any time.

With any window open.

34 / 40

What can side to side surge cause?

A spontaneous combustion.

A roll over.

An increase in speed.

An engine system failure.

35 / 40

What gauge on the dashboard indicates electrical system charging rate?

The ammeter/voltmeter

The power gauge

The air gauge

The coolant pressure gauge

36 / 40

What does the amount of liquid allowed in the tank depend on?

The size of the tank.

The legally allowed weight limits.

All answers listed.

Whether and how much the liquid will expand during the trip.

37 / 40

In the event of an accident you should remember to do the following EXCEPT:

notify authorities

stop any bleeding and keep the victims warm

protect the area

move the victims out of the way immediately

38 / 40

Select the true statement about empty trucks:

They can take longer to stop than a truck with a full tank.

All answers listed.

They have better traction on wet roads than full tanks.

They come to a stop faster when you use only the emergency brake.

39 / 40

Which of the following statements is true about speed management?

The posted speed limit is safe for all conditions.

All of these answers are correct.

You should be able to stop within the distance that you can see ahead.

Speed limits for buses are the same as cars.

40 / 40

You should_____to uncouple the converter dolly.

disconnect the safey chains, lower the landing gear, and chock the wheels

chock the wheels, lower the landing gear, and disconnect the safey chains

chock the wheels, disconnect the safety chains, and then lower the landing gear

lower the landing gear, disconnect the safety chain, and chock the wheels

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