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

You need to be extra careful when driving smooth bore tanks:

When hauling food or milk products.

All answers listed.

When unloading or loading.

When stopping or starting.

2 / 40

How do you know when your brakes are fading?

to control your speed on a downgrade you have to apply less pressure to the break pedal

the brake pedal flops to the cabin floor

to control your speed on a downgrade you have to push harder on the brake pedal

your speed increases when pressure is removed from the brake pedal

3 / 40

What placards, if any, do you need if your load includes 20 pounds of Division 2.3 gas and 1,001 pounds of flammable gas?

None, you cannot load these materials together.

Poison 23 and dangerous.

Just dangerous placards are required.

Poison 23 and flammable gas 21.

4 / 40

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

Air pressure gauge

Coolant pressure gauge

Voltmeter gauge

Oil pressure gauge

5 / 40

Drivers placard their vehicle to _____ the risk.

take away

minimize

elevate

communicate

6 / 40

What should you do before you begin to couple?

activate the spring brakes

position the fifth wheel beforehand

check your path for any hazards

inspect the condition of the frame of the tractor

7 / 40

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

it stays about the same

it increases by two times

it increases by four times

none of these answers are correct answers are correct

8 / 40

The reason a bulk liquid tanker is hard to handle is:

Because the cargo has a low center of gravity.

Because the cargo has a high center of gravity.

Because of the high friction point.

Because the cargo has a high density.

9 / 40

The purpose for the emergency air line is:

supply air to the trailer air tanks and on combination vehicles, controls the service brakes

supply air to the tractor air tanks and on combination vehicles controls the emergency brakes

to supply air to the trailer air tanks and, on combination vehicles, controls the emergency brakes

none of the answers listed

10 / 40

Select the true statement about dual air brake systems.

there is a single set of brake controls

all of these answers are correct

there is a primary system and a secondary system

one system controls the front axle and the other controls the rear axle

11 / 40

What is the best way to prevent brakes form overheating while drive down a steep grade?

use countersteering practices

use the stab braking method

drive at a speed of 5 mph below your safe speed

use the trailer brakes only

12 / 40

What does the service brake system do?

they are part of an official vehicle inspection

under normal driving it applies and releases the brakes by using the brake pedal

they are only on vehicles that have hydraulic brakes

they are valves that maintain air tank pressure

13 / 40

Where can you find a shipper’s certification?

On the original shipping paper.

It is a separate document that all hazmat drivers must keep in their vehicles.

There is no such thing.

On all packages.

14 / 40

What are you checking when looking at the lubrication level on a dipstick?

The oil level

The horn fluid level

The power steering fluid level

The windshield wiper fluid level

15 / 40

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

it controls when the brakes will be applied

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

it controls when the warning system is activated

it controls when air is released from the storage tank

16 / 40

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

directly in front of the trailer

above 12 degrees to the right of the trailer

about 12 degrees to the left of the trailer

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

17 / 40

The best way to have control on curves is:

you do not need to do anything different

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

keep pressure on the brake pedal through the turn

to shift to a lower gear before entering the curve

18 / 40

The main reason you should pull the dolly out from under a trailer before disconnecting it from the trailer in front is:

to provide additional lateral stabilization to the front trailer

it is possible that the dolly tow bar could fly up making it difficult to re-couple

removing the dolly before uncoupling is not the correct procedure

so the rear-trailer's air brake system will stay charged and keep the trailer wheels locked to prevent rolling

19 / 40

Select which is not an engine compartement belt:

A power steering belt

A safety belt

A water pump belt

An air compressor belt

20 / 40

The best way to describe a dual air brake system is:

all of these answers are correct

there are 2 separate air brake systems that have their own hoses, lines etc

there are 2 separate air brake systems that supply air to the trailer if there is one

there is a primary and secondary system that is 2 separate air brake systems

21 / 40

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

8 seconds

15 seconds

13 seconds

10 seconds

22 / 40

The belt that you need to make sure is securely mounted, without frays, and adjusts and latches properly is the:

The power steering belt

The seat/safety belt

The water pump belt

The air compressor belt

23 / 40

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

On the package and on paperwork at the shipping destination.

On the shipping papers and on the package.

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

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

24 / 40

____is what can legally hold the parking brake or emergency brake in position for a bus, truck, or truck tractor.

Air pressure

Spring pressure

All of these answers are correct

Brake pressure

25 / 40

The emergency air line is used to:

provide back up air pressure

to alert emegency services when there is a problem

engage the trailer brakes when there is an air pressure loss

engage the tractor's front brake when there is air pressure loss

26 / 40

If students must cross the street, when they get off the bus, which statement is true?

If the bus is equipped with the crossing gate, the danger of running over the child is eliminated.

The student should wait to cross the street until the bus continues on its route.

When the driver signals that it is safe to proceed, the students must run across the street to reduce the exposure to danger.

For crossing, students should make eye contact with the bus driver and wait for the driver's signal that it is safe to proceed.

27 / 40

Which of the following is NOT an appropriate reason to flash your braking lights?

to alert drivers behind you that there are hazards ahead

to signal to tailgaters that they are too close to your vehicle

to warn vehicles approaching you from behind that you are driving slowly

to warn drivers behind you when you need to slow down

28 / 40

What is a passive railway crossing?

The type of crossing on which the driver does not have to stop.

The type of crossing with no cross buck sign.

The type of crossing where you can pass the tracks without stopping.

The type of crossing, which does not have any type of traffic control device.

29 / 40

Puddles or dripping fluids from the underside of the transmission and engine may indicate:

A leaking line or hose

A leak from the engine

All of these answers are correct

Problems with the water pump

30 / 40

What will happen should a driver cross the air lines when hooking up the an older trailer?

the hand valve will activate the tractor brakes instead of the trailer brakes

the brake pedal will activate the trailer spring brakes instead of the air brakes

none of the answers listed

if there are no spring brakes, you can drive on but there will be no trailer brakes

31 / 40

If you are carrying Division 1.2 or 1.3 materials, how far away must you park from the traveled portion of the roadway?

At least twenty feet

At least five feet

At least ten feet

At least half a mile

32 / 40

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

mid position

normal

lowered

raised

33 / 40

A portable tank differs from a cargo tank in that ______.

portable tanks are bulk containers, which are permanently attached to a vehicle

none of these answers are correct

portable tanks are bulk containers, which are not permanently attached to a vehicle

cargo tanks are bulk containers, which are not permanently attached to a vehicle

34 / 40

While driving at night, which lights should you use as often as you can?

novelty lights

emergency flashers

high beams

low beams

35 / 40

How often should you drain your air tanks?

at the end of each shift

at the end of each trip

at the end of each week

at the beginning of each month

36 / 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

none of the answers listed

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

37 / 40

When accelerating:

speed up smoothly and gradually and avoid jerking

always use the parking brake to slow down

"hammer down" when your wheels start to spin

do not engage the clutch before you take your foot off the brake

38 / 40

Select the true statement about emergency brakes:

they are required to be activated the loss of air pressure

all of these answers are correct

they are required on all commercial vehicles

they are required to be held on by a mechanical force

39 / 40

The trailer height is correct for connecting a converter dolly to a second trailer when:

the kingpin is resting behind the fifth wheel

the trailer will slightly lower when the converter dolly backed under it

the top of the kingpin lines up with the locking jaws

the trailer will slightly rise when the converter dolly is backed under it

40 / 40

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

have the trailer kingpin centered over the fifth wheel

have the tractor and trailer aligned

back under the trailer at an angle

back under the trailer in a straight path

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