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

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

exhaust

air brake system

fifth wheel

none of the answers listed

2 / 40

In what position should the converter dolly air tank drain valves and pintle hook be in?

closed and latched

open and latched

open and open

closed and open

3 / 40

Is it important to look into the back of the fifth wheel to see if the lockpin is locked in?

yes

only every 7 days

only at the end of the shift

4 / 40

How should you know when to shift?

road speed and wind speed

engine speed and the shift indicator light

engine speed and road speed

every 3 to 5 seconds or engine speed

5 / 40

What is the minimum amount of distance you should maintain when driving at 50 mph in ideal conditions with a 100 ft twin trailer combination?

13 seconds

6 seconds

11 seconds

8 seconds

6 / 40

Water is drained from the compressed air tanks because:

braking power is decreased due to the low boiling point of water

to keep the oil in the air compressor clean

the water could freeze in cold weather and cause braking failure

the water will over cool the compressor

7 / 40

Select the false statement about suspension:

Check for distorted or broken coil springs.

Check for broken or cracked spring hangers.

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

Check for shifted, missing, or cracked leaf springs.

8 / 40

The _____of the kingpin has the locking jaw close around it.

shank

dull section

apex

tip

9 / 40

Where is compressed air stored?

in the storage tank

in the gasoline tank

in the hose lines

in the compartment for the engine

10 / 40

Select the true statement about stop valves in a cargo tank:

They protect the piping and tank during rear end collisions.

They will fall off in an emergency.

They will close in an emergency.

They are manually operated.

11 / 40

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

Place transmission in park or neutral and set parking brake.

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

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

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

12 / 40

When should you check your mirrors for a lane change?

Right after starting the lane change.

After completing the lane change.

All of these answers are correct.

Before and after signaling the change.

13 / 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 halfway open position

in an open position

in a closed position

in a 1/3 way open position

14 / 40

In Column 1 the symbol "I" means:

International transportation.

Invalid substance.

Iodine.

International restrictions.

15 / 40

How many seats may be placed in the aisle if the bus is a charter and is carrying agricultural (farm) workers?

16 / 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 half a mile

At least ten feet

At least twenty feet

At least five feet

17 / 40

Which of the following materials would be an acceptable floor liner for moving Division 1.1 or 1.2 materials?

Stainless steel

Carbon steel

Non-ferrous metal

All of these answers are correct

18 / 40

Which of the following factors is NOT used to determine your safe speed when going down a long steep downgrade?

total weight of the vehicle and cargo

length and steepness of grade

time of day

weather

19 / 40

Why should you cover cargo?

because many states require it

to protect individuals from any spilled cargo

all of these answers are correct

to protect your cargo from bad weather

20 / 40

Another term for a smooth bore tank is:

A tank that is made out of stainless steel.

A liquid tank that does not have baffles.

A tank that is easily portable.

A liquid tank that has baffles.

21 / 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

22 / 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

23 / 40

The safety valve is usually set to open at:

150 psi

125 psi

75 psi

225 psi

24 / 40

How often should you check the tires if your placarded trailer has dual tires?

Check tires every 3 hours or 150 miles.

Check tires every 4 hours or 200 miles.

Check tires every hour or 75 miles.

Check tires every 2 hours or 100 miles.

25 / 40

You must control how far packages labeled "Radioactive II" or "Radioactive III" are located from people and cargo space walls by referring to:

The table of hazardous materials.

The transport index and the separation distances table.

The segregation and separation chart.

The list of hazardous materials and reportable quantities.

26 / 40

This object should not have any missing parts, be fully raised, the crank handle is secured, and that there is no damage to the frame.

Landing gear

Drop arm

Lifts/doors/tires

Release arm

27 / 40

When arriving at the destination announce:

The location.

The next departure time.

The reason for stopping.

All of these answers are correct.

28 / 40

If there is no traffic light or attendant, how far from the draw of a drawbridge must you stop?

5 feet

100 feet

30 feet

50 feet

29 / 40

Select the true statement about double or triple trailers.

they can roll over due to abrupt steering movements

they present a rearward amplification hazard

all answers listed

they can have a dangerous "crack the whip" effect

30 / 40

Hazardous materials (that are not forbidden) carried on a bus must be:

Stored in the passenger compartment

All of these answers are correct

Carried in a metal box

Labeled

31 / 40

This component should be checked that it is solid, securely bolted to the tracture frame, and clear of objects.

The platform

The catwalk

The fifth wheel

The locking kingpin

32 / 40

What is the normal operating range for a truck's oil pressure?

40-60 psi

20-30 psi

This is engine-specific

30-75 psi

33 / 40

The direction of liquid movement not prevented by baffles is:

Bottom to top.

Side to side.

Back to front.

None of the answers listed.

34 / 40

On a drawbridge, you do not need to stop, but must slow down and make sure it's safe, when:

The bridge has an attendant or traffic officer who controls traffic whenever the bridge opens.

There is a traffic light showing green.

Both of these answers are correct.

None of these answers are correct.

35 / 40

Select the factor that has no effect on how much liquid you can carry:

The legal amount of weight you can carry of any particular liquid.

The density of the liquid.

The liquid's weight.

How much the liquid will expand in transport.

36 / 40

When should air tanks be drained?

at the end of each working day

at every restroom break stop

they don't need to be drained

every 7 days

37 / 40

Select the reason as to why air tanks need to be drained:

tanks usually do not need to be drained

to provide greater control of your vehicle

to release water and other contaminents which may cause brakes to fail in freezing weather

to prevent the left sided brake from locking up

38 / 40

Surge affects the handling of a tanker by:

Increasing the wind drag.

Allowing you to take tighter turns.

None of the answers listed.

Moving the truck in the direction the liquid flows in.

39 / 40

Select the true statement in regards to an application pressure gauge:

it prevents the brakes from failing

when accelerating it releases air

it is connected to the generator

it shows how much air pressure you are applying to the brakes

40 / 40

The floor liner for explosives may not:

Contain any of these materials.

Contain nails or screws.

Contain steel or iron.

Contain cracks or holes.

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