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

Carry-on baggage cannot be stored:

On the seats.

Under the seat.

In the aisles and stairwells.

Behind the seats.

2 / 40

Select the statement that describes how you could damage the landing gear.

back under the trailer in a straight path

have the tractor and trailer aligned

back under the trailer at an angle

have the trailer kingpin centered over the fifth wheel

3 / 40

What are some of the important parts in the steering system?

rim, lug nuts, tire

main spring, axle, spring shackle

tie rod, spindle, pitman arm

leaf spring, vehicle frame, torque rod

4 / 40

The CDL manual indicates the last step on picking up students at the bus stop is as follows:

Open the service door just enough to activate the alternating red light when traffic is in a safe distance from the bus.

Place transmission in park or neutral and set parking brake.

Make a final check to confirm all traffic stops before opening the bus door and signaling students to approach.

Activate the amber flashing caution lights to warn vehicles that the bus will stop to load passengers soon.

5 / 40

What do you do first during step 3 of starting the engine and inspecting the inside of the cab?

Shift the gear to neutral.

Listen for any unsual noises after starting the engine.

Make sure the parking brake is activated after getting in the cab.

Start the engine after getting in the cab.

6 / 40

Which trailer is most likely to tip over due to the crack the whip effect?

the heaviest trailer

the last trailer of a double

the last trailer of a triple

the first trailer of a triples

7 / 40

What is the purpose of the supply pressure gauge?

to inform you of how much air is in the tank

all of these answers are correct

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

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

8 / 40

The crack-the-whip effect is more likely to cause the front trailer to tip over.

there is an equal chance for trailers to tip

false

trailers never tip

true

9 / 40

To inspect the______you should pump the pedal 3 times and hold it down for 5 seconds while making sure the pedal doesn't move during those 5 seconds.

air brakes

engine brakes

hydraulic brakes

parking brakes

10 / 40

Select the true statement about empty trucks:

they have a smaller stopping distance than full trailers

empty trucks stop in the same distance as a fully loaded truck

empty trailers are easier to stop because there is not cargo shifting

they have poor traction due to wheel lockup and bouncing

11 / 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 head to the closest mechanic

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

continue on with your trip

decrease your speed and test the other system

12 / 40

You should adjust all the outside left and right side convex mirrors to see:

The right and left front tires touching the ground.

200 feet behind the bus.

The children's exit path out of the main bus door.

The entire area to the rear of the mirror along the side of the bus.

13 / 40

How far before a railroad crossing should you stop your bus?

10 to 35 feet

50 to 75 feet

100 feet exactly

15 to 50 feet

14 / 40

If you are already carrying 100 pounds of silver cyanide, what precautions must you take if you are given papers at a dock to carry 100 cartons of battery acid?

Make sure the battery acid is loaded on top of the silver cyanide.

Make sure the silver cyanide is loaded on top of the battery acid.

Make sure there is plenty of space between the two.

Inform someone and not load the battery acid.

15 / 40

Before backing under the trailer you should______when coupling a tractor and trailer with air lines already connected.

supply air to the trailer system and then pull the air supply knob out

press down on the brake pedal twice

have the trailer brakes off

all answers listed

16 / 40

The brake pushrod should not move more than____for manual slack adjusters.

movement is not allowed

checking is not required in vehicles built after 1994 as they have automatic slack adjusters

1-2 inches while the brakes are set

an inch when pulled by hand with the brakes released

17 / 40

Tires should should be replaced:

when there are broken valve stems

if the tread depth on your front tires is less than 4/32 deep

when the tread separates

all of these answers are correct

18 / 40

Which of the following statements is FALSE?

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

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

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

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

19 / 40

If you double your speed, what will happen to your stopping distance?

it increases by two times

it increases by four times

none of these answers are correct answers are correct

it stays about the same

20 / 40

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

the trailer will jackknife

the tractor will continue moving in a straight line no matter how you turn the steering wheel

none of the answers listed

the rig will continue straight ahead but will slide sideways

21 / 40

Students exit the bus and walk:

At least 10 feet away from the side of the bus.

The distance it takes to clear the danger zone.

Across the street.

At least 8 feet away from the side of the bus.

22 / 40

It is important to know the outage required for the liquids you carry because:

Tank baffles may not always be permitted with outage.

Some of the denser liquids don't need any.

None of these answers are correct.

Some liquids will expand more than others when warm.

23 / 40

Which seats must have a seat belt:

Women and children seats.

Senior citizen seats.

All of these answers are correct.

The driver's seat.

24 / 40

Select the true statement:

Lighter vehicles requiring more braking power to stop compared to heavier vehicles.

A "bobtail" tractor will take longer to stop than a combination vehicle that is fully loaded down to the maximum weight.

Wait as long as possible to brake when driving a heavy vehicle.

None of the answers listed.

25 / 40

At the end of each shift you should:

All of these answers are correct.

Inspect your bus.

Report any defects.

Report any damage.

26 / 40

When inspecting the ______you are making sure that the lines and hoses are not chafed, cut, pinched, or dragged against tractor parts.

mud flaps

electric/air lines

air brake lines

lifts/door/ties

27 / 40

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

For fresh air

Whenever you enter a tunnel

Never

First day of spring

28 / 40

Where are the two main places where the hazardous material identification number appears?

On the shipping papers and on the package.

On the package and on paperwork at the shipping destination.

On the package and on paperwork at the shipping point of origin.

On the shipping papers and on a secret document in the driver's wallet.

29 / 40

Start by___when coupling.

backing the converter dolly under the second trailer

coupling the tractor to the second trailer

having the second trailer against the dock

coupling the converter hook to the pintle tongue of the first trailer

30 / 40

Why should you not use the trailer hand brake to straighten out a jack knifing trailer?

the tractor wheels caused the skid in the first place once the trailer wheels grip the road again, the trailer will start to push the tractor and straighten out

this is the only situation in which you should use the hand brake

the trailer wheels caused the skid in the first place once the trailer wheels grip the road again, the trailer will start to follow the tractor and straighten out

none of the answers listed

31 / 40

Select the true statement in regards to a converter dolly:

none of the answers listed

it is a coupling device with one or two axles and a fifth wheel with which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig

it is a connecting device consisting of one axle which disconnects a semitrailer combination vehicle converting it into two separate trailers

it is a coupling device with only two axles and a sixth wheel to which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig

32 / 40

When must a driver’s inspection report be completed?

At the end of each shift.

All of these answers are correct.

Only if defects are found.

Before driving your bus.

33 / 40

This carries hydraulic fluid or air to the wheel brake assemby.

Connector rods

Brake lines/hoses

Brake drums

Slack pieces

34 / 40

What should you check for when inspecting a converter dolly?

that the converter dolly air tank drain valve is in the closed position

all answers listed

that the spare tire is secured if there is one

that the safety chains are secured to the trailer

35 / 40

An "A/W" the first column of the hazardous materials table means:

This material has no restrictions when shipped by air and/or water.

There is no restrictions with this material if shipped by water only.

It is ok to ship this material by air only.

This material is only restricted when shipped by air and/or water.

36 / 40

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

15 seconds

13 seconds

8 seconds

10 seconds

37 / 40

Select the false statement about suspension:

Check to make sure torsion bars and/or arms are lubricated.

Check for shifted, missing, or cracked leaf springs.

Check for broken or cracked spring hangers.

Check for distorted or broken coil springs.

38 / 40

A commercial motor vehicle (CMV) is defined as:

a vehicle with a gross weight over 26,001 lbs

a vehicle transporting 16 or more passengers

all of these answers are correct

a vehicle transporting hazardous materials

39 / 40

What are some things you should check on the front of your vehicle when doing the walk-around inspection?

oil, transmission, air compressor, radiator

tires, steering parts, suspension parts, headlights

windshield, wipers, mirrors, hood latches

low beams, high beams, four way flashers, turn signals

40 / 40

You should line up_____when getting ready to back under the trailer.

about 12 degrees to the left of the trailer

for the kingpin to activate on the driver's side first

directly in front of the trailer

above 12 degrees to the right of the trailer

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

CDL Category Practice Tests

CDL Practice Test

How To Get An iowa Commercial Drivers License

Hit the Open Road

iowa CDL License Test Tips

Additional Information

Information on the Iowa Department of Transportation

Additional Iowa CDL Helpful Links

iowa
CDL Practice Test