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 most dangerous time during the school bus ride is:

On long bus journeys.

When loading and unloading students.

When the students become unruly on the bus.

Crossing railway crossing.

2 / 40

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

For hazards not described in the hazmat manual

During an emergency

Always

Never

3 / 40

What might happen if you swing wide to the left before you turn right?

you might damage your leaf springs

someone might try to pass you on your right

all of these answers are correct

someone might try to pass you on your left

4 / 40

You should have the fifth wheel plate greased as recommened because:

it will ensure a good air line connection

it will reduce noise and heat

it will prevent steering problems

it will ensure a good electrical connection

5 / 40

When must a driver’s inspection report be completed?

Only if defects are found.

All of these answers are correct.

At the end of each shift.

Before driving your bus.

6 / 40

When should you check your mirrors for a lane change?

All of these answers are correct.

After completing the lane change.

Right after starting the lane change.

Before and after signaling the change.

7 / 40

Your rig should be parked on__to uncouple double trailers.

grass

a downgrade

level ground

the company's lot

8 / 40

To avoid rollover when going through a curve, the best thing to do is:

Drive at a speed below the posted speed limit.

Drive at a speed higher than the posted speed limit.

Ride the brakes through the curve.

Pump the brakes through the curve.

9 / 40

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

the rig will continue straight ahead but will slide sideways

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

none of the answers listed

the trailer will jackknife

10 / 40

What does it mean when the safety valve releases air?

there is too much air in the air compressor

pressure has passed 150 psi

all of these answers are correct

you need it to have it checked out by a mechanic because something is wrong

11 / 40

Which trailer should be the first one after the tractor?

the trailer that weighs the most

the trailer that weighs the least

the trailer that is the shortest in length

none of the answers listed

12 / 40

A shipper’s certification is best described as _____.

a paper certification from the manufacturer given to the shipper

a paper certification given to the manufacturer from the shipper

a test for shippers that certifies that they are qualified to package hazardous materials

a certification that the package has been prepared according to the rules when the shipper packages hazardous materials

13 / 40

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

You are a non-smoker.

You are loading at night and need the headlights.

You need the engine to run the pump.

The material does not need a placard.

14 / 40

Which trailer is more likely to roll over when pulling 3 trailers?

the last trailer

the first trailer

the tractor

the second trailer

15 / 40

What is the value of the overhead rear-view mirror inside of the bus?

To monitor the driver's appearance.

To provide visibility directly in the back of the bus.

To check blind spots.

To monitor passenger activity.

16 / 40

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

The size of the tank.

The legally allowed weight limits.

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

All answers listed.

17 / 40

To be sure that air is supplied to the second trailer:

keep an eye of the air gauge for a drop of 30 psi

open the emergency line shut off at the back of the second trailer

crank the engine brake

while driving at 10 mph, use the hand valve. The vehicle should stop in the same distance of a single trailer moving at 5 mph

18 / 40

The most stable tanker shape is:

Square

Round

Elliptical

Cylindrical

19 / 40

What should you do if you start a trailer skid?

use your trailer hand brake

release the brakes to get traction back

quickly step on the brakes

slowly apply a firm pressure to the brakes

20 / 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.

21 / 40

What is a passive railway crossing?

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

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

The type of crossing with no cross buck sign.

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

22 / 40

On a bus, you may sometimes haul small-arms ammunition, emergency shipments of drugs, or hospital supplies. The total weight of all such hazardous materials must not be greater than:

250 pounds

100 pounds

300 pounds

500 pounds

23 / 40

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

All of these answers are correct

Problems with the water pump

A leak from the engine

A leaking line or hose

24 / 40

What is the most important reason for doing a vehicle inspection?

federal and state laws require you to inspect your vehicle

to insure that you will achieve the best gas mileage

safety for yourself and other road users

to save you money by preventing costly repairs

25 / 40

You should____to check the free play of manual slack adjusters on S-Cam brakes.

chock the wheels and release the parking brakes after parking on a level ground

after parking on a slight grade, release the parking brake, activate the service brakes and check for vehicle movements

apply the parking brake after stopping on level ground

drain off air pressure before adjusting after parking on level ground

26 / 40

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

The liquid's weight.

How much the liquid will expand in transport.

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

The density of the liquid.

27 / 40

How should the hand valve be used?

to test the trailer brakes

when the trailer is fully loaded down

only in emergency situations

only in conjuction with the foot brake

28 / 40

What is the best way to stop all skids?

restore traction back to the tires

accelerate and countersteer

use controlled or stab braking

quickly turn the steering wheel side to side

29 / 40

The 3 parts of the air brake system are: service brakes, parking brakes, and ____.

bolt brakes

v-cam brakes

disc brakes

foot brakes

30 / 40

At around____the governor allows the air compressor to start pumping again:

100 psi

225 psi

125 psi

175 psi

31 / 40

Select the true statement about empty trucks:

They have better traction on wet roads than full tanks.

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

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

All answers listed.

32 / 40

An air system that is fully charged will typically have ___ psi of pressure.

250

200

125

33 / 40

Which of the following statements about downshifting is NOT true?

downshift before entering a curve

downshift before starting down a hill

downshift before climbing a hill

downshift when you get to the bottom of a hill

34 / 40

How should you inspect a converter dolly?

as if it is an engine

as if it is cargo

as if it is an axle with a fifth wheel

as if it is a trailer

35 / 40

You must carry a gas mask with you when transporting:

Flammable materials

Liquid gas

Poison

Chlorine

36 / 40

A "transport index" relates to products that are:

Radioactive

Liquid

Meant for human consumption

Overweight

37 / 40

How do you secure a second trailer to your combination vehicle?

none of the answers listed

use emergency air brakes, spring brakes, and wheel chocks together

use wheel chocks only

use the emergency air brakes or the trailer's spring brakes only

38 / 40

Remember to____when connecting the converter dolly to the rear trailer.

ensure that the landing gear is slighty off of the ground

lock the trailer brakes

all answers listed

check the trailer height

39 / 40

While driving on a clear night with low beam headlights, you should be able to stop within:

2 lengths of your vehicle.

Half of a football field.

The distance you will travel in the next 20 seconds.

The distance you can see ahead of you.

40 / 40

You should expect____when backing a tractor under a trailer.

the trailer to be completely still

the trailer to lift slightly

the trailer landing gear to be fully extended

the end of the kingpin to be level with the top of the fifth wheel

Your score is

The average score is 62%

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