25 realistic Hazardous Materials practice questions for Iowa CDL applicants. Required for: Drivers transporting placarded hazardous materials. Official test: 30 questions, 24 correct to pass.
Question 1 of 25 · HazMat Driving
Drivers must avoid which of these areas when transporting HazMat?
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A.
Tunnels and bridges where prohibited
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B.
Heavily populated areas when alternative routes exist
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C.
Open flames or heat sources
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D.
All of the above
Correct answer: D.
Avoid restricted areas, populated zones, and any ignition sources.
Question 2 of 25 · HazMat Driving
Which is true about smoking near HazMat vehicles?
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A.
Smoking is fine while driving
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B.
Smoking is prohibited within 25 feet of certain materials
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C.
Smoking is allowed at truck stops
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D.
Smoking is allowed in residential areas
Correct answer: B.
Smoking is forbidden within 25 feet of explosives, oxidizers, and flammables.
Question 3 of 25 · Parking
Some HazMat vehicles cannot be parked within how many feet of a bridge, tunnel, or building?
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A.
100 feet
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B.
200 feet
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C.
300 feet
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D.
500 feet
Correct answer: C.
Class 1 (explosives) generally must not be parked within 300 feet of bridges, tunnels, or buildings.
Question 4 of 25 · HazMat Driving
When can drivers smoke around a HazMat vehicle?
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A.
While driving only
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B.
When parked at a truck stop
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C.
Never within 25 feet of certain materials
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D.
Whenever convenient
Correct answer: C.
Smoking is forbidden within 25 feet of HazMat including explosives, oxidizers, or flammables.
Question 5 of 25 · Placards
Placards are warning signs placed on:
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A.
Drivers' shirts
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B.
The outside of vehicles transporting HazMat
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C.
The shipping papers only
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D.
Inside the cab
Correct answer: B.
Diamond-shaped placards on the four sides of the vehicle warn others of hazardous cargo.
Question 6 of 25 · Emergency Equipment
Which of the following is a sign of a tire fire?
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A.
Smoke from the tire
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B.
A loud noise
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C.
Vibration in the steering
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D.
All of the above
Correct answer: D.
Watch for smoke, noise, and vibration as warning signs of a tire fire.
Question 7 of 25 · CDL Rules
What does the letter "H" represent on a CDL?
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A.
Hazardous materials endorsement
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B.
Heavy vehicle endorsement
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C.
Highway driving endorsement
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D.
Hauling endorsement
Correct answer: A.
The H endorsement allows a CDL holder to transport placarded hazardous materials.
Question 8 of 25 · Loading
What does the term "marking" refer to?
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A.
Marking the shipper's name on the package
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B.
Putting the proper shipping name and ID number on the package
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C.
Marking the truck's plates
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D.
Marking the route on a map
Correct answer: B.
Marking includes the proper shipping name and the four-digit ID number on the package.
Question 9 of 25 · Parking
When can a HazMat shipment be left unattended?
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A.
Whenever the driver leaves the vehicle
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B.
Only in safe locations such as a carrier facility
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C.
Anywhere with a sign
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D.
Only on private roads
Correct answer: B.
HazMat must be attended unless parked at a carrier facility or other approved location.
Question 10 of 25 · Hours of Service
Drivers transporting hazardous materials must keep a written record of duty status because:
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A.
It's a federal regulation for HazMat operations
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B.
Insurance requires it
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C.
It looks professional
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D.
Drivers don't need to keep records
Correct answer: A.
Federal hours-of-service rules apply to HazMat drivers as to other CMV drivers.
Question 11 of 25 · Emergencies
When must drivers inform the carrier and emergency responders during a HazMat emergency?
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A.
As soon as it's safe to do so
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B.
When they reach the destination
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C.
Only after the cargo is unloaded
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D.
Only if asked
Correct answer: A.
Notify carrier and authorities immediately as soon as you can safely do so.
Question 12 of 25 · Shipping Papers
HazMat shipping papers must be:
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A.
Out of the driver's reach
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B.
Within the driver's reach while driving and clearly distinguished from other shipping papers
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C.
In the trailer with the cargo
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D.
Mailed to the receiver in advance
Correct answer: B.
Shipping papers must be within reach and identifiable. They must be on the seat or in a door pouch.
Question 13 of 25 · Placards
What does "subsidiary hazard class" mean?
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A.
A secondary hazard a material poses
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B.
A backup placard
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C.
A small package
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D.
A vehicle accessory
Correct answer: A.
Some materials have a primary and a subsidiary hazard class for additional risks.
Question 14 of 25 · Placards
Green placards usually indicate:
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A.
Compressed gases (non-flammable)
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B.
Explosives
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C.
Poisons
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D.
Corrosives
Correct answer: A.
Green placards usually indicate non-flammable compressed gases.
Question 15 of 25 · Emergencies
Which of these is the best advice if you have a HazMat leak?
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A.
Continue to the destination
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B.
Stop, secure the area, communicate the danger, get help
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C.
Try to repair it yourself
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D.
Cover the leak
Correct answer: B.
Stop, secure, communicate, and get qualified help. Don't try to handle leaks yourself.
Question 16 of 25 · Shipping Papers
Which of these documents must accompany the HazMat?
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A.
Shipping papers
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B.
Hazard placards
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C.
Emergency response info
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D.
All of the above
Correct answer: D.
Shipping papers, placards, and emergency info must all accompany the load.
Question 17 of 25 · HazMat Basics
What's the most important reason for these regulations?
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A.
Public safety
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B.
Protect the environment
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C.
Protect the carrier
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D.
All of the above
Correct answer: D.
Regulations protect people, property, and the environment.
Question 18 of 25 · Emergency Equipment
Which type of fire is most likely to occur with HazMat?
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A.
Tire fires
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B.
Electrical fires
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C.
Engine compartment fires
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D.
All of the above
Correct answer: D.
Any of these can occur — pre-trip and en-route inspections reduce risk.
Question 19 of 25 · Placards
Which of these is required if a vehicle's placards are missing or destroyed?
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A.
Placards must be replaced before continuing
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B.
Drivers can continue without placards
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C.
Drivers must call OSHA
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D.
Drivers must wait until next shipping point
Correct answer: A.
Replace missing or damaged placards immediately before continuing.
Question 20 of 25 · Rail Crossings
What is the maximum stopping distance allowed for HazMat vehicles approaching a railroad crossing?
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A.
Stop within 15-50 feet of the nearest rail and not closer than 15 feet
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B.
Stop on the tracks
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C.
Stop only when train is approaching
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D.
No stop required
Correct answer: A.
HazMat vehicles must stop 15 to 50 feet from the nearest rail before crossing.
Question 21 of 25 · HazMat Driving
When transporting Class 1 explosives, the driver must:
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A.
Park anywhere convenient
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B.
Have a written route plan and follow it
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C.
Drive only at night
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D.
Drive only on local roads
Correct answer: B.
Drivers must have a route plan and avoid populated areas where possible.
Question 22 of 25 · Security
Which is true about HazMat security?
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A.
Drivers should keep doors locked when stopped
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B.
Drivers should never leave the vehicle unattended
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C.
Drivers must follow the carrier's security plan
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D.
All of the above
Correct answer: D.
All these practices reduce theft and tampering risk for HazMat.
Question 23 of 25 · HazMat Driving
Drivers transporting Division 1.1, 1.2, or 1.3 explosives may NOT:
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A.
Take a route that goes through tunnels prohibiting explosives
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B.
Refuel at any station
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C.
Travel during business hours
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D.
Cross any state line
Correct answer: A.
Avoid tunnels and routes prohibiting explosives. Use only approved routes.
Question 24 of 25 · Shipping Papers
What information must a HazMat driver have on the bills of lading?
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A.
Total quantity by weight or volume
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B.
Number and type of packages
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C.
Shipping name and hazard class
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D.
All of the above
Correct answer: D.
All of these must be included for HazMat shipments.
Question 25 of 25 · HazMat Driving
When transporting HazMat over long distances, drivers should:
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A.
Stay alert, take rest breaks, and inspect the load regularly
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B.
Drive at maximum speed limit
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C.
Skip rest stops to save time
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D.
Avoid highways
Correct answer: A.
Stay alert with regular rest breaks; inspect cargo at every stop.
About the Hazardous Materials Test
The Hazardous Materials (HazMat) test covers the rules for transporting materials that pose a risk to health, safety, and property. Topics include the hazardous materials table, shipping papers, marking, labeling, placarding, loading and unloading, bulk packaging, driving and parking rules, communications, emergencies, and hazardous materials regulations enforced by the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration. A federal Transportation Security Administration (TSA) background check is also required.
The Iowa Department of Transportation — Motor Vehicle Division administers this knowledge test as part of its commercial driver license program. To earn the HazMat Endorsement (H) on your Iowa CDL, you need to score at least 24 out of 30 on the official version.
Topics covered on this practice test
- HazMat Driving: 6 questions
- Placards: 4 questions
- Shipping Papers: 3 questions
- Parking: 2 questions
- Emergency Equipment: 2 questions
- Emergencies: 2 questions
- CDL Rules: 1 question
- Loading: 1 question
- Hours of Service: 1 question
- HazMat Basics: 1 question
- Rail Crossings: 1 question
- Security: 1 question
How to use this practice test
- Read each question carefully. CDL questions are written precisely — small wording differences matter.
- Click "Show Answers & Explanations" only after answering every question. Don't peek mid-test.
- Read the explanation for every question, even ones you got right. The reasoning is more important than the answer.
- Repeat the test until you score 100%. The questions are deterministic per state, so you can track your improvement over multiple sessions.
- Move on to the other endorsement tests for Iowa until you're ready for the official exam.
Tips specific to the Hazardous Materials test
HazMat is the longest knowledge test (30 questions) and adds a Transportation Security Administration (TSA) background check. Most candidates struggle with placard colors, the segregation table, shipping paper requirements, and emergency response procedures. Use the official Emergency Response Guidebook (ERG) alongside this practice set.