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

If you must stop on the shoulder of the road, you should place warning devices at all of the following places except...

about 100 feet behind your vehicle

on the other side of a divided highway

within 10 feet of the front or rear corners

about 100 feet in front of your vehicle

2 / 40

What does outage mean?

It is how quickly the tanks drain.

It is the weight of the liquid.

It is the allowance needed for the expansion of liquid.

It is the movement of the liquid.

3 / 40

What is the purpose of cladding in a tanker?

It protects the tanker form any corrosive cargo.

It eliminates liquid surge.

It protects the cargo from changes in temperature.

It controls the temperature of the cargo.

4 / 40

Of the following hazardous material classes, which is the most dangerous?

Division 63

Division 61

Division 62

Division 64

5 / 40

Some city transit buses may have a brake-door interlock system, this system:

Works when the rear door is open.

Releases the brakes.

Should be used in place of the parking brake.

Should be used in emergencies.

6 / 40

Which of the following will confirm that you are driving with anti-lock brakes?

Red indicator lamp on the brake cylinder.

The bus operators manual.

The certification on the driver side door.

Yellow abs malfunction lamp on the instrument panel will light when you start the engine.

7 / 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.

engine brakes

hydraulic brakes

air brakes

parking brakes

8 / 40

Select the true statement:

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

None of the answers listed.

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

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

9 / 40

What will occur if you cross the connect the air lines?

the tractor will not be able to move

the tractor brakes will lock up

there will not be air going to the trailer brakes

nothing will occur, it'll funciton as normal

10 / 40

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

1-2 inches while the brakes are set

movement is not allowed

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

an inch when pulled by hand with the brakes released

11 / 40

A hazard class that uses transport indexes to determine the amount that can be loaded in a single vehicle is _____.

Class 6 poisons

Class 1 explosives

Class 7 radioactive materials

Class 3 flammable liquids

12 / 40

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

dull section

tip

apex

shank

13 / 40

Your bus is disabled. With riders aboard, the bus may be towed or pushed to a safe place only:

By another bus with its four-way flashers on.

If getting off the bus would be more risky for the riders.

By a 27,000 lbs gvwr or larger tow truck.

If the distance is less than 500 yards.

14 / 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

15 / 40

Where should you place your warning devices if you must stop on a one-way or divided highway?

100 feet, 200 feet, and 300 feet toward approaching traffic

50 feet, 100 feet, and 150 feet toward approaching traffic

20 feet, 50 feet, and 100 feet toward approaching traffic

10 feet, 100 feet, and 200 feet toward approaching traffic

16 / 40

Air pressure should build___with a dual air system.

from 70 to 125 psi in 60 seconds

from 60 to 100 psi in 45 seconds

from 85 to 100 psi in 45 seconds

from 50 to 80 psi in 60 seconds

17 / 40

You are driving a 40 foot truck at 35 MPH, how much space (in seconds) should you keep in front of you?

3 seconds

6 seconds

4 seconds

5 seconds

18 / 40

Tires should should be replaced:

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

all of these answers are correct

when there are broken valve stems

when the tread separates

19 / 40

This object is required to be checked for damage, that it's secure, and strong enough to handle any cargo.

The fifth wheel

The apron

The platform

The header board

20 / 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?

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

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

None of these answers are correct.

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

21 / 40

The best way to go into a curve is to decrease your speed going into the curve and then ____going through it.

shift down 2 gears

ride the brake

none of the answers listed

slightly accelerate

22 / 40

Which of the following types of emergency equipment must you have on your bus?

Fire extinguisher, spare electric fuses, and reflectors.

Spare electric fuses, fire extinguisher, and accident reporting kit.

Hydraulic jack, fire extinguisher, and signal flares.

Reflectors, fire extinguisher, and accident reporting kit.

23 / 40

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

a fully loaded trailer behind the tractor

any trailer

the last trailer of a triple

the last trailer of a double

24 / 40

What should you hear when you test the trailer brakes by opening the service air line at rear of trailer with the hand valve on?

the emergency air line will release air

you should hear air escape from the open valve

none of the answers listed

the service brakes will move to a fully applied position

25 / 40

Select the two reasons as to why special care is needed when driving a tank vehicle:

The chance of rollover and of spontaneous combustion.

The danger of surge and the high center of gravity.

The danger of surge and the low center of gravity.

None of the answers listed.

26 / 40

You should_____when the low pressure warning is activated:

come to a safe stop while you still have control of the brakes

wait until the air brakes kick in automatically

maintain highway speed and keep an eye on your air pressure gauge

pump the brake pedal to come to a stop immediately

27 / 40

Bus drivers must have a CDL if they drive a vehicle:

Designed to seat more than 16 or more persons, including the driver.

That is designed to carry more than nine passengers.

That has a gross weight rating of more than 26,000 pounds.

That has air brakes.

28 / 40

How much space should there be between the lower and upper fifth wheel?

zero

1 to 2 inches

1/4 to 1/2 of an inch

it is dependent on the load you are carrying

29 / 40

Select the statement of what you should not do if you are required to drive through flowing water or deep puddles.

quickly turn the steering wheel side to side

drive at a high speed

shift into a lower gear

increase engine rpm

30 / 40

When inspecting your bus, you must make sure that:

Every handhold and railing is secure.

Rider signaling devices are working.

All of these answers are correct.

Emergency exit handles are secure.

31 / 40

When conducting a pre-trip inspection, the most important item to verify is _____.

that the radio transmits a signal

that there are no leaks in the air brake system

that the tire tread is sufficient for the expected driving conditions

that the registration is in the cup holder

32 / 40

Air tanks should be drained:

manually when the automatic devices fail

all of these answers are correct

at the end of each shift or day

to prevent sludge from clogginng up the brake system valves

33 / 40

Select the definition of "off-tracking."

it is wheen the rear wheel skid and the front wheels maintain a straight path

it is when the trailer wheels go in a different direction from the front wheels

it is when the rear wheels of the vehicle follow a different path way than that of the front wheels

none of the answers listed

34 / 40

What is the safest way to stop unruly behavior on the bus?

Pull off the road in a safe location, secure the bus, stand up, and tell the students what behavior you expect of them.

Keep checking the rear view mirror so you can see what happened and report to the principal.

Have the unruly students move to the front of the bus.

Yell loudly for the students to sit down and behave themselves.

35 / 40

There should be ___space between the upper and lower fifth wheel after coupling.

1/12 inch

none of the answers listed

1/30 inch

1/8 inch

36 / 40

A commercial motor vehicle (CMV) is defined as:

all of these answers are correct

a vehicle transporting hazardous materials

a vehicle transporting 16 or more passengers

a vehicle with a gross weight over 26,001 lbs

37 / 40

Secure baggage and freight in ways that avoid damage and:

Protect riders from injury if carry-ons fall or shift.

Allow the driver to move freely and easily.

All of these answers are correct.

Allow riders to exit by any window or door in an emergency.

38 / 40

Select the true statement in regards to managing the space to the sides:

high wind gusts will not cause any issues for doubles or triples

you should drive down the center of both lanes over the pavement markings

you should try to avoid driving next to others when possible

you should always keep your vehicle to the right side of the lane

39 / 40

For any flatbed load you must have at least ____ tie downs.

six

two

four

one

40 / 40

Anti-lock brakes:

Lengthen stopping distance.

Are not available in mosst busses.

Work only when you activate in-cab switch.

Keep your wheels from locking during hard brake application.

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