Colorado Hazardous Materials (H) practice test
30 questions · 80% to pass · Required to haul placarded hazardous loads.
How to use this practice test
Read each question, click an answer, and the correct choice is highlighted with a short explanation referencing the underlying CDL Manual concept. Your live score appears at the top of the page. Refresh to reset.
This test runs entirely in your browser. Nothing is uploaded; no account is required. Pages refresh to a new randomized cut from the bank.
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1. Smoking is prohibited within how many feet of a placarded hazmat vehicle?
Explanation. No smoking within 25 feet of a placarded vehicle containing flammable hazmat.
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2. Class 7 placards are for:
Explanation. Class 7 is radioactive material.
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3. During a pre-trip inspection, the hazmat endorsement requires:
Explanation. Federal law requires a TSA security threat assessment in addition to the written test. (Reinforcement variant — same underlying CDL Manual concept.)
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4. When taking the CDL knowledge exam, hazmat marking on a package includes:
Explanation. Markings include the proper shipping name and 4-digit ID number. (Reinforcement variant — same underlying CDL Manual concept.)
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5. Hazardous materials are divided into how many hazard classes?
Explanation. There are nine hazard classes under 49 CFR.
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6. When operating a CMV in interstate commerce, hazardous materials are divided into how many hazard classes?
Explanation. There are nine hazard classes under 49 CFR. (Reinforcement variant — same underlying CDL Manual concept.)
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7. Class 8 hazmat is:
Explanation. Class 8 covers corrosive materials such as acids and bases.
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8. Placards must be displayed on:
Explanation. Four placards: front, rear, left, and right.
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9. According to the FMCSA CDL Manual, the shipper must certify on the shipping papers that:
Explanation. The shipper certification states the shipment meets DOT regulations. (Reinforcement variant — same underlying CDL Manual concept.)
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10. Class 3 hazmat is:
Explanation. Class 3 is flammable liquid.
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11. When operating a CMV in interstate commerce, when loading hazmat, the engine should be:
Explanation. Engine should be off during cargo loading unless it powers a transfer pump. (Reinforcement variant — same underlying CDL Manual concept.)
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12. According to the FMCSA CDL Manual, the Emergency Response Guidebook (ERG) is published by the:
Explanation. The ERG is published by the U.S. Department of Transportation. (Reinforcement variant — same underlying CDL Manual concept.)
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13. You must placard your vehicle when carrying any amount of:
Explanation. Certain materials in any quantity (Table 1) require placards regardless of amount.
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14. Experienced commercial drivers know that routes for hazmat may be restricted by:
Explanation. States and many cities designate or prohibit specific routes for hazmat. (Reinforcement variant — same underlying CDL Manual concept.)
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15. When taking the CDL knowledge exam, a "subsidiary hazard" placard:
Explanation. Subsidiary placards display additional hazards beyond the primary classification. (Reinforcement variant — same underlying CDL Manual concept.)
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16. When taking the CDL knowledge exam, shipping papers for hazmat must be:
Explanation. Shipping papers must be in the driver pouch on the door, on the seat, or in the driver reach when seated. (Reinforcement variant — same underlying CDL Manual concept.)
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17. In real-world commercial driving, hazmat marking on a package includes:
Explanation. Markings include the proper shipping name and 4-digit ID number. (Reinforcement variant — same underlying CDL Manual concept.)
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18. When taking the CDL knowledge exam, tank vehicles transporting hazmat must:
Explanation. Cargo tanks have specific design, marking, and placarding rules. (Reinforcement variant — same underlying CDL Manual concept.)
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19. A "subsidiary hazard" placard:
Explanation. Subsidiary placards display additional hazards beyond the primary classification.
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20. Per federal regulations, when a hazmat shipment is delivered, you must:
Explanation. Documentation must remain with the shipment as required. (Reinforcement variant — same underlying CDL Manual concept.)
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21. The hazmat endorsement requires:
Explanation. Federal law requires a TSA security threat assessment in addition to the written test.
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22. Most state DMV CDL handbooks state that smoking is prohibited within how many feet of a placarded hazmat vehicle?
Explanation. No smoking within 25 feet of a placarded vehicle containing flammable hazmat. (Reinforcement variant — same underlying CDL Manual concept.)
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23. When operating a CMV in interstate commerce, drivers carrying hazmat must have:
Explanation. You must have shipping papers, the proper placards displayed, and emergency response information accessible. (Reinforcement variant — same underlying CDL Manual concept.)
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24. Tank vehicles transporting hazmat must:
Explanation. Cargo tanks have specific design, marking, and placarding rules.
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25. Per federal regulations, reporting a hazmat incident to the National Response Center is required:
Explanation. Specific incident criteria require an immediate NRC call (1-800-424-8802). (Reinforcement variant — same underlying CDL Manual concept.)
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26. When loading hazmat, the engine should be:
Explanation. Engine should be off during cargo loading unless it powers a transfer pump.
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27. Reporting a hazmat incident to the National Response Center is required:
Explanation. Specific incident criteria require an immediate NRC call (1-800-424-8802).
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28. You discover a leak in a hazmat shipment. You should:
Explanation. Park safely away from traffic, secure the area, and contact emergency responders. Do not move the vehicle if leaking.
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29. In real-world commercial driving, you must placard your vehicle when carrying any amount of:
Explanation. Certain materials in any quantity (Table 1) require placards regardless of amount. (Reinforcement variant — same underlying CDL Manual concept.)
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30. A driver must check tires of a placarded hazmat vehicle:
Explanation. Tires must be examined at trip start and at every stop.
About the Hazardous Materials (H) exam
The Hazardous Materials endorsement allows a CDL holder to transport materials regulated under 49 CFR. Applicants must pass a TSA threat-assessment background check in addition to a written exam covering hazard classes, the Emergency Response Guide, placarding, shipping papers, segregation rules, loading and unloading, security plans, and route restrictions.
This Colorado-specific edition uses the same federal source material every U.S. state adopts. The Colorado DMV administers the actual exam at its service centers. Bring your CDL handbook for any last-minute reference; it’s free at every Colorado DMV office.
Once you’re consistently scoring above 90% on this practice set, you’re well above the 80% required to pass the official Colorado exam. Drill the questions you miss most often, then take the test cold once a day for a week leading up to your appointment.
Tips that actually work
- Read every answer choice before clicking. CDL questions are famous for "best answer" wording where two choices look right.
- Don’t memorize question text — learn the underlying rule. The DMV reshuffles wording constantly.
- Keep a list of the questions you miss. Re-drill them in isolation until you can’t miss them.
- Practice in short, frequent sessions. Two 20-minute sessions per day beats one two-hour cram.
What happens after I pass?
Passing the knowledge test earns you a Commercial Learner’s Permit (CLP). You must hold the CLP for at least 14 days before you can take the road skills test, and you must drive with a CDL-holding instructor in the cab during that period. Once you pass the road skills test, your CDL is issued.