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

Suspension systems:

keep the axles in place

keep the steering wheel tight

keep the brake drums from failing

keep the load secure

2 / 40

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

electric/air lines

mud flaps

air brake lines

lifts/door/ties

3 / 40

The school bus driver may be the only contact person from school system some parents meet. The percentage of such parents is as high as:

0.72

0.85

0.65

0.5

4 / 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

you will need it to open the side box

so you don't lose it

you will need it to inspect the trailer

5 / 40

Select which is not an engine compartement belt:

A water pump belt

A power steering belt

An air compressor belt

A safety belt

6 / 40

Select the true statement in regards to empty trucks:

they require a shorter stopping distance than a fully loaded trailer

they may have poor traction due to bouncing and wheel lockup

they are easier to stop because there isn't cargo shifting in the trailer

none of the answers listed

7 / 40

When is it acceptable for non-hazardous materials to be described by hazard class words or identification numbers?

During an emergency

Always

Never

For hazards not described in the hazmat manual

8 / 40

The Emergency Response Guidebook (ERG):

Is studied by emergency personnel to help keep the public safe.

Contains an index of hazardous material id numbers, which is why you must label things correctly.

Was created by the national department of transportation, so it is used nationwide.

All of these answers are correct.

9 / 40

The locking jaws of the kingpin should close around:

the shank

the apex

the tip

the base

10 / 40

Which of the following hazard classes utilizes a transport index in order to determine how much of it can be loaded on a single vehicle for transport?

Class 3—flammable liquids

Class 1—explosives

Class 4—live chickens

Class 7—radioactive materials

11 / 40

The air leakage rate for combination vehicles should not be more than _ psi a minute.

12 / 40

Select the true statement in regards to handing triples and doubles

none of the answers listed

a sudden movement of the steering wheel may result in the rear trailer tipping over

due to the crack the whip effect, the rear trailer of a 100 foot triple is less likely to tip than a single trailer

due to off tracking, a triple bottom rig can come to a stop quicker than a 5 axle semi trailer

13 / 40

When driving with multiple trailers, which one should be right behind the tractor?

the trailer with the smallest road

the trailer with the heaviest load

the trailer longest in length

the trailers shortest in length

14 / 40

When inspecting your bus, you must make sure that:

Emergency exit handles are secure.

Every handhold and railing is secure.

Rider signaling devices are working.

All of these answers are correct.

15 / 40

An emergency escape ramp should be used _____.

only in ideal conditions

any time the truck experiences a significant loss of braking power

only when it is raining

only when not carrying a load

16 / 40

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

10 seconds

8 seconds

15 seconds

13 seconds

17 / 40

The parking brakes should be used____in air brake vehicles.

only when parked on an incline

every time the vehicle is parked

only during post trip inspection

as rarely as possible

18 / 40

Select the true statement in regards to the braking power of spring brakes.

it depends on the adjustment of the service brakes

braking power can only be tested by licensed mechanics

the braking prower increases when the brakes are hot

it will not be affect by the condition of the service brakes

19 / 40

What do you check when doing a visual inspection of the coupling?

the locking jaw is closed around the kingpin and there is no space beween the lower and upper fifth wheel

that the locking jaw is closed around the kingpin and that there is no space between the upper and lower fifth wheel

none of the answers listed

that the locking jaw is open around the kingpin and that there is some space between the lower and upper fifth wheel

20 / 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

21 / 40

Before pulling away, make sure the landing gear of the trailer is:

Down and that the handle is hanging free.

Raised and that the handle is secured.

Raised and that the handle is hanging free.

Down and that the handle is secured.

22 / 40

If you are traveling at 55 mph in a 30-foot vehicle, you should leave how many seconds of following distance?

7 seconds

3 seconds

6 seconds

4 seconds

23 / 40

With the controlled braking method, you _____?

apply the brakes as hard as you can without locking the wheels

apply the brakes all the way until the wheels lock up, release the brakes and apply them again when the wheels start to roll again

lightly apply braking pressure

repeatedly tap the brakes as fast as you can

24 / 40

Why should you test the tractor protection valve?

all answers listed

to avoid the emergency brakes kicking on due to loss of air

to avoid loss of air from the air hose

to avoid loss of air from the trailer brakes

25 / 40

Which of the following statements is FALSE?

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

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

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

26 / 40

The compressor is connected to the engine via _____?

v-belt or gears

lines

stag gears

r-belt

27 / 40

If your engine runs a pump used during delivery of compressed gas, should you turn off the engine before or after unhooking hoses after delivery?

None of these answers are correct.

Turn it off during product transfer, while unhooking the hose.

Turn it off before product transfer, before you hook the hose.

Turn it off after product transfer, before you unhook the hose.

28 / 40

The amount of liquid you can carry depends on:

How much the liquid will expand during the trip.

How much you can legally carry.

The density or weight of the liquid.

All answers listed.

29 / 40

You should turn off your engine when loading flammable liquid unless:

You need the engine to run the pump.

You are loading at night and need the headlights.

The material does not need a placard.

You are a non-smoker.

30 / 40

If there is not a sight glass to check the oil level you are required to look for leaks around the _____.

brake pads

transmission

axle seals/hub oil

wheel rims

31 / 40

Which of these statements about speed management and braking is true?

The posted speed limit will always allow you to stop safely.

Stopping time increases by one second for each 10 mph over 20 mph.

You need about four times as much stopping distance at 40 mph as at 20 mph.

The total stopping distance of a bus is the distance it takes to stop once the brakes are applied.

32 / 40

If you are driving a 100-foot truck with double trailers at 30 mph in dry conditions, how many seconds of space should there be between your truck and other vehicles?

33 / 40

Drivers placard their vehicle to _____ the risk.

elevate

communicate

minimize

take away

34 / 40

Where is compressed air stored?

in the gasoline tank

in the storage tank

in the hose lines

in the compartment for the engine

35 / 40

Select the statement that describes smooth bore tanks:

They are 1 large tank.

They are divided with holes from liquid to flow through controlling surge.

None of the answers listed.

They are divided down into smaller tanks.

36 / 40

With most hazardous materials, you may park within 5 feet of the road briefly, if your work requires it. The materials that are the exception and do not allow parking this close to the road are:

Acids and poisons

Liquids

Corrosives and oxidizers

Explosives A and B

37 / 40

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

air brake system

fifth wheel

exhaust

none of the answers listed

38 / 40

If you are required to stop at railroad crossings, you must:

All of these answers are correct.

Proceed only when you are sure no train is coming.

Stop 15 to 50 feet before the nearest rail.

Remember to never shift gears while crossing tracks.

39 / 40

Select the true statement about converter dollies:

because of their small size they have little braking power

they usually do not have spring brakes

all answers listed

they typically require a glad hand converter

40 / 40

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

all answers listed

have the trailer brakes off

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

press down on the brake pedal twice

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