Hazardous Materials knowledge test

CDL Placarding Questions

Placarding is the part of the Hazmat test that is pure rule following. Placards are the diamond-shaped warnings on the outside of the vehicle that tell everyone else what you are carrying, and whether you need them comes down to which of two tables your material sits in.

What the test asks about placarding

The manual splits materials into Table 1 and Table 2. Table 1 materials have to be placarded whenever any amount is transported, with no threshold at all. Table 2 hazard classes need placards only when the total amount is 1,001 pounds or more including the package, and bulk packaging is treated separately. That total is a sum: you add the amounts from every shipping paper for all the Table 2 products on board, not each product on its own. Getting the table wrong is how a driver ends up hauling an unplacarded load that legally required placards.

Where drivers lose marks

  • Applying a weight threshold to Table 1 materials. Any amount of a Table 1 material requires placards.
  • Weighing each Table 2 product separately. You add the amounts across all shipping papers for all Table 2 products in the vehicle.
  • Forgetting the package counts. The 1,001 pound figure includes the packaging, not just the material.
  • Confusing placards with labels. Placards go on the vehicle, while the diamond-shaped labels on individual packages warn dockworkers and drivers handling them.
  • Missing the DANGEROUS placard option, which can replace separate placards when you have 1,001 pounds or more of two or more Table 2 classes.

How to study itWork out which table a material is in first, then ask about weight only if it is Table 2. Answering in that order removes most of the difficulty in these questions.

50 Placarding practice questions with answers

Every question below is followed by the correct answer and an explanation of why it is right. Read through them, then take the timed Hazardous Materials test to see how you do without the answers in front of you.

1. Which of the following is considered a Table 1 material, requiring a placard for any amount transported?

  • A. Class 3 (Flammable Liquid).
  • B. Class 2.3 (Poison Gas). (correct answer)
  • C. Class 8 (Corrosive).
  • D. Class 9 (Miscellaneous).

Why: Class 2.3 (Poison Gas) is a Table 1 material, which means it requires a placard regardless of the weight or volume transported.

2. A shipper offers you a non-bulk load of Class 4.3 (Dangerous When Wet) material weighing 10 pounds. Do you need a placard?

  • A. No, non-bulk loads under 1,001 pounds do not need placards.
  • B. Yes, Class 4.3 is a Table 1 material and requires a placard for any amount. (correct answer)
  • C. Only if transporting it across state lines.
  • D. No, because solid materials under 100 pounds are exempt.

Why: Class 4.3 (Dangerous When Wet) is a Table 1 material. You must placard the vehicle for any amount transported.

3. You are transporting 600 pounds of Flammable Liquid (Class 3) and 600 pounds of Corrosive material (Class 8). What placards can be legally displayed?

  • A. No placards are required.
  • B. Either the specific Flammable and Corrosive placards, or the DANGEROUS placard. (correct answer)
  • C. Only the DANGEROUS placard.
  • D. Only the Flammable and Corrosive placards.

Why: The total weight is 1,200 pounds (over 1,001 lbs). Because it is a mixed load of Table 2 materials and neither exceeds 2,205 lbs at one facility, you may use either the specific placards or the DANGEROUS placard.

4. During your pre-trip inspection, you notice your loaded hazmat trailer is missing the right-side placard, but the other three are present. What must you do?

  • A. Drive to a truck stop to purchase a replacement.
  • B. Write the hazard class on a piece of paper and tape it to the right side.
  • C. Do not move the vehicle until a proper replacement placard is affixed to the right side. (correct answer)
  • D. Move the vehicle, as three placards provide sufficient warning.

Why: A placarded vehicle must not be operated unless all four required placards are properly attached and clearly visible.

5. If a vehicle is transporting a mix of Class 1.1, 1.2, and 1.3 Explosives, which placard is required?

  • A. Only the Explosives 1.1 placard. (correct answer)
  • B. All three specific Explosives placards.
  • C. The DANGEROUS placard.
  • D. The Explosives 1.3 placard.

Why: When a transport vehicle contains Class 1.1, 1.2, and 1.3 Explosives, it only requires the placard representing the highest hazard, which is Explosives 1.1.

6. Under DOT regulations, can a FLAMMABLE placard be used in place of a COMBUSTIBLE placard on a cargo tank?

  • A. No, this is a strict violation of placarding rules.
  • B. Yes, a FLAMMABLE placard may be used in place of a COMBUSTIBLE placard. (correct answer)
  • C. Only if the material has a flashpoint above 200 degrees Fahrenheit.
  • D. Only during the winter months.

Why: According to DOT placarding exceptions, a FLAMMABLE placard may be used in place of a COMBUSTIBLE placard.

7. If a placard is placed on a vehicle surface that is a similar color to the placard itself, what must be done to ensure visibility?

  • A. The placard must have a dotted or solid outer boundary line or be on a contrasting background. (correct answer)
  • B. The vehicle surface behind the placard must be painted black.
  • C. The placard must be illuminated by a dedicated spotlight.
  • D. No action is required if it is securely mounted.

Why: Placards must have a contrasting background or have a dotted or solid line outer border if placed on a background of a similar color.

8. Is it legal to drive a vehicle displaying a hazmat placard if the vehicle contains no hazardous materials?

  • A. Yes, if you are en route to pick up a hazardous load.
  • B. Yes, to encourage other motorists to keep a safe following distance.
  • C. No, it is illegal to display placards when the vehicle does not contain the corresponding hazmat or residue. (correct answer)
  • D. Yes, as long as the driver holds a valid Hazmat endorsement.

Why: It is illegal to display hazmat placards on a vehicle that does not contain hazardous materials or empty tanks with hazmat residue.

9. How must text on a placard be oriented for readability?

  • A. Vertically, reading from top to bottom.
  • B. Diagonally along the edge of the diamond.
  • C. Horizontally, reading from left to right. (correct answer)
  • D. From any angle, as long as the colors are visible.

Why: Placards must be oriented so that the text and symbols can be read horizontally from left to right.

10. If a multi-compartment cargo tank carries different liquid hazardous materials in different compartments, how must the UN numbers be displayed?

  • A. Only the UN number of the most hazardous material is required.
  • B. The UN numbers for each material must be displayed in the correct compartment order on the sides. (correct answer)
  • C. A single generic UN number can be used for all compartments.
  • D. UN numbers are not required for multi-compartment tanks.

Why: When a cargo tank has multiple compartments holding different materials, the correct UN numbers must be displayed on the sides in the same order as the compartments.

11. What is the minimum amount of a Table 1 hazardous material that requires placarding?

  • A. 1,001 pounds.
  • B. 500 pounds.
  • C. Any amount. (correct answer)
  • D. 119 gallons.

Why: Table 1 materials, such as Poison Gas, Explosives 1.1, and Dangerous When Wet, require a placard when any amount is transported.

12. Do empty non-bulk packages that previously contained hazardous materials generally require the vehicle to be placarded?

  • A. Yes, always.
  • B. No, empty non-bulk packaging does not generally require placarding. (correct answer)
  • C. Yes, but only with the DANGEROUS placard.
  • D. Only if the material was a Combustible liquid.

Why: Unlike unpurged bulk tanks, empty non-bulk packages (like cardboard boxes or small drums) do not generally require vehicle placarding, unless they contain residue of certain highly toxic materials like Poison Inhalation Hazards.

13. When must you use a COMBUSTIBLE placard on a vehicle transporting non-bulk packages of combustible liquids?

  • A. When the total weight exceeds 1,001 pounds.
  • B. When the total weight exceeds 5,000 pounds.
  • C. Placards are not required for non-bulk packaging of combustible liquids. (correct answer)
  • D. For any amount transported.

Why: Combustible liquids transported in non-bulk packaging (e.g., standard drums or boxes) do not require placards, regardless of the weight.

14. When are placards required for transporting Class 9 (Miscellaneous) hazardous materials in domestic US transportation?

  • A. For any amount transported.
  • B. Only when transported in a bulk packaging. (correct answer)
  • C. When the weight exceeds 1,001 pounds in non-bulk packaging.
  • D. Class 9 materials never require placards.

Why: For domestic transportation in the United States, Class 9 placards are not required for non-bulk packages, but they are required for bulk packaging.

15. Who is primarily responsible for providing the required hazmat placards?

  • A. The motor carrier.
  • B. The driver.
  • C. The shipper. (correct answer)
  • D. The receiver.

Why: The shipper is responsible for offering the proper placards to the motor carrier unless the carrier's vehicle is already correctly placarded.

16. You are transporting 400 pounds of Flammable Liquid (Class 3) and 500 pounds of Corrosive material (Class 8). Neither is a bulk packaging. What placards are required?

  • A. Flammable and Corrosive.
  • B. DANGEROUS.
  • C. No placards are required. (correct answer)
  • D. Flammable only.

Why: The total weight of these Table 2 materials is 900 pounds. Because the total is under 1,001 pounds, no placards are required for non-bulk packaging.

17. When can you legally remove placards from a cargo tank that previously contained hazardous materials?

  • A. As soon as the liquid has been drained from the tank.
  • B. When returning the empty tank to the terminal.
  • C. Only after the tank is reloaded with a non-hazardous material.
  • D. When the tank has been sufficiently cleaned of residue and purged of vapors. (correct answer)

Why: Empty cargo tanks must remain placarded until they have been sufficiently cleaned of residue and purged of vapors to remove any potential hazard.

18. A non-bulk shipment contains 100 pounds of Poison Gas (Table 1) and 800 pounds of Flammable Liquid (Table 2). Which placards are required?

  • A. Both Poison Gas and Flammable placards.
  • B. Only the DANGEROUS placard.
  • C. Only the Poison Gas placard. (correct answer)
  • D. No placards are required.

Why: Table 1 materials (Poison Gas) require a placard for any amount. The Table 2 material (Flammable Liquid) is under 1,001 pounds, so it does not require a placard.

19. When sliding a placard into a placard holder on a trailer, what must the driver ensure regarding visibility?

  • A. The placard must be entirely visible, and the edges of the holder must not obscure any part of the text or symbols. (correct answer)
  • B. The holder must cover the hazard class number to protect it from road debris.
  • C. The holder must be painted to match the placard.
  • D. The placard must be taped securely over the holder frame.

Why: Placards must be fully visible. Placard holders must not cover or obscure any of the symbols, text, or hazard class numbers on the placard.

20. When displaying UN identification numbers on a panel adjacent to the placard, what color must the panel be?

  • A. White.
  • B. Yellow.
  • C. Orange. (correct answer)
  • D. Red.

Why: UN identification numbers may be displayed on a rectangular orange panel placed closely to the required placards.

21. You have a shipment of exactly 1,001 pounds of Class 8 (Corrosive) material in non-bulk packaging. Do you need a placard?

  • A. Yes, you must display the Corrosive placard. (correct answer)
  • B. No, placards are only needed at 1,002 pounds.
  • C. Only if you travel interstate.
  • D. Yes, but you can use the DANGEROUS placard.

Why: Because the weight has reached the 1,001-pound threshold for a Table 2 material, the vehicle must display the specific Corrosive placard.

22. If the 4-digit UN identification number is not displayed directly in the center of the placard, where else must it be displayed?

  • A. On an orange panel placed adjacent to the placard. (correct answer)
  • B. On a white sign taped to the rear bumper.
  • C. Written on the vehicle doors with permanent marker.
  • D. Inside the cab on the dashboard.

Why: If the UN identification number is not displayed on the placard, it must be displayed on a rectangular orange panel placed near the placard.

23. If a placarded trailer is disconnected and dropped at a facility, what are the requirements for the placards?

  • A. They must be removed immediately by the driver.
  • B. They must remain securely attached and visible from all four sides. (correct answer)
  • C. Only the front placard needs to remain visible.
  • D. They can be covered with a tarp until a tractor returns.

Why: If a placarded trailer is parked or dropped, the placards must remain properly displayed and visible on all four sides until the trailer is unloaded or cleaned.

24. What is the standard required size of a hazmat placard?

  • A. At least 12 inches on each side.
  • B. At least 8.5 inches on each side.
  • C. At least 9.84 inches (250 mm) on each side. (correct answer)
  • D. At least 10.75 inches on each side.

Why: Standard hazard warning placards must measure at least 9.84 inches (250 mm) on all sides.

25. Which specific hazard requires a specialized placard with a square white background border?

  • A. Poison Inhalation Hazard.
  • B. Dangerous When Wet.
  • C. Highway Route Controlled Quantity (HRCQ) of Radioactive materials. (correct answer)
  • D. Explosives 1.1.

Why: A square white background must surround the placard for shipments of Highway Route Controlled Quantities (HRCQ) of Class 7 Radioactive materials.

26. What is the requirement for placards regarding durability and weather resistance?

  • A. They must withstand a 30-day exposure to open weather conditions without deteriorating or becoming illegible. (correct answer)
  • B. They must be made of metal or rigid plastic only.
  • C. They must be replaced every 90 days regardless of condition.
  • D. They must be waterproofed with a clear plastic shield.

Why: Federal regulations require that placards be capable of withstanding a 30-day exposure to open weather conditions without substantial deterioration.

27. What should you do if your assigned vehicle has faded placards where the hazard class number is illegible?

  • A. Trace over the hazard class number with a black permanent marker.
  • B. Replace the damaged or faded placards before moving the vehicle. (correct answer)
  • C. Ask the receiver to replace them upon delivery.
  • D. Drive during daytime hours only to ensure they can be seen.

Why: Placards that are faded, damaged, or illegible must be replaced before the vehicle is operated on public highways.

28. What must a driver do if a placard gets covered in thick mud during transit?

  • A. Continue to the destination and let the receiver clean it.
  • B. Stop at a safe location and clean the placard so it is clearly visible. (correct answer)
  • C. Report the obscured placard to the dispatcher within 24 hours.
  • D. Remove the placard since it can no longer be read.

Why: Drivers must ensure placards are maintained in good condition and kept clear of dirt, mud, or snow so they remain clearly visible at all times.

29. Can you use the DANGEROUS placard to represent a mixed load entirely made of Table 1 materials?

  • A. Yes, if the weight exceeds 1,001 pounds.
  • B. Yes, to save space on the trailer.
  • C. No, the DANGEROUS placard cannot be used for Table 1 materials. (correct answer)
  • D. Only if the shipper specifically requests it.

Why: The DANGEROUS placard can only be used for mixed loads of Table 2 materials. Table 1 materials must always display their specific hazard placards.

30. At what total weight do Table 2 hazardous materials generally require placards?

  • A. 1,001 pounds or more. (correct answer)
  • B. 501 pounds or more.
  • C. 10,001 pounds or more.
  • D. Any amount.

Why: When transporting hazardous materials covered by Table 2, placards are required when the total gross weight is 1,001 pounds or more.

31. If you are driving a tractor-trailer that requires placards, where can the front placard be legally mounted?

  • A. It must be mounted on the windshield of the tractor.
  • B. It must be mounted on the nose of the trailer only.
  • C. It may be on the front of the tractor or the front of the trailer, as long as it is clearly visible. (correct answer)
  • D. It may be omitted if the tractor is red.

Why: The front placard can be mounted on the front of the trailer or on the front of the tractor (cab or bumper), provided it is clearly visible to oncoming traffic.

32. What is the mandatory shape of a standard hazardous materials placard?

  • A. Square.
  • B. Circular.
  • C. Rectangular.
  • D. Square-on-point (diamond). (correct answer)

Why: Hazardous materials placards must be displayed in a square-on-point (diamond) orientation.

33. You load 2,500 pounds of Flammable Gas and 1,000 pounds of Corrosive material at a single facility. Can you use the DANGEROUS placard for this load?

  • A. Yes, because there are two Table 2 materials totaling over 1,001 pounds.
  • B. No, because you loaded 2,205 pounds or more of Flammable Gas at one place; you must use its specific placard. (correct answer)
  • C. Yes, because Flammable Gas and Corrosive materials are compatible.
  • D. No, because gases are never allowed to be grouped under a DANGEROUS placard.

Why: You cannot use the DANGEROUS placard if you load 2,205 pounds (1,000 kg) or more of a single Table 2 material at one facility. You must use the specific placard for that material.

34. Which subset of Organic Peroxides is treated as a Table 1 material, requiring a placard for any amount?

  • A. All Organic Peroxides.
  • B. Type B, temperature controlled. (correct answer)
  • C. Type F, liquid.
  • D. Only solid Organic Peroxides.

Why: Organic Peroxide, Type B, temperature controlled is a Table 1 material and requires placarding for any amount.

35. How many identical placards are required on a typical commercial vehicle transporting a placarded load?

  • A. Two (front and rear).
  • B. Three (rear and both sides).
  • C. Four (front, rear, and both sides). (correct answer)
  • D. One (on the rear only).

Why: A placarded vehicle must have at least four identical placards, placed on the front, rear, and both sides.

36. If a bulk packaging contains a primary hazard of Class 8 (Corrosive) and a subsidiary hazard of Class 4.3 (Dangerous When Wet), what placarding is required?

  • A. Only the Corrosive placard.
  • B. Only the Dangerous When Wet placard.
  • C. Both the Corrosive and Dangerous When Wet placards. (correct answer)
  • D. The DANGEROUS placard.

Why: Materials with a subsidiary hazard of Dangerous When Wet (Class 4.3) or Poison Inhalation Hazard require both the primary and subsidiary placards to be displayed.

37. How far must a hazmat placard be placed from any other markings or lettering on the vehicle?

  • A. At least 1 inch.
  • B. At least 3 inches. (correct answer)
  • C. At least 6 inches.
  • D. At least 12 inches.

Why: Placards must be kept clear of any other markings, lettering, or dirt. They must be located at least 3 inches (76 mm) away from any other markings.

38. If you are transporting a material that requires a POISON INHALATION HAZARD placard, what is the rule regarding other required placards?

  • A. It replaces all other primary hazard placards.
  • B. It must be displayed in addition to any other required primary hazard placards. (correct answer)
  • C. It is only required for shipments exceeding 5,000 pounds.
  • D. It must be placed only on the front of the vehicle.

Why: The POISON INHALATION HAZARD placard must be displayed in addition to any other placards required by the primary hazard class of the material.

39. Placards must be located clear of appurtenances and devices. Which of the following is considered an appurtenance?

  • A. Ladders, pipes, doors, and tarpaulins. (correct answer)
  • B. The vehicle's steering wheel.
  • C. The driver's side mirrors.
  • D. The vehicle's transmission.

Why: Placards must be placed securely and clear of obstructions like ladders, pipes, doors, tarpaulins, or the splash of tires.

40. A shipment contains 200 pounds of Explosives 1.1 (Table 1) and 1,500 pounds of Corrosives (Table 2). What placards are required?

  • A. Only the Explosives 1.1 placard.
  • B. The DANGEROUS placard.
  • C. Both the Explosives 1.1 and the Corrosive placards. (correct answer)
  • D. Only the Corrosive placard.

Why: Explosives 1.1 requires a placard for any amount. The Corrosive material exceeds 1,001 pounds, so it also requires its specific placard. Table 1 materials cannot use the DANGEROUS placard.

41. You have a shipment of exactly 1,000 pounds of Class 8 (Corrosive) material in non-bulk packaging. Do you need a placard?

  • A. Yes.
  • B. No. (correct answer)
  • C. Only the DANGEROUS placard.
  • D. Only if it is a liquid.

Why: The regulation states that Table 2 materials require placards when the gross weight is 1,001 pounds or more. Exactly 1,000 pounds does not require a placard.

42. While en route, who is ultimately responsible for ensuring the placards remain in place and clearly legible?

  • A. The shipper.
  • B. The driver. (correct answer)
  • C. The DOT inspector.
  • D. The receiving facility.

Why: Once on the road, the driver is responsible for inspecting the vehicle and ensuring placards remain attached, visible, and legible.

43. Which of the following is a Table 2 material, requiring a placard only when the total weight is 1,001 pounds or more?

  • A. Class 4.3 (Dangerous When Wet).
  • B. Class 1.1 (Explosives).
  • C. Class 3 (Flammable Liquid). (correct answer)
  • D. Class 7 (Radioactive Yellow III).

Why: Class 3 (Flammable Liquid) is a Table 2 material. It requires a placard only when the aggregate gross weight is 1,001 pounds or more.

44. What specific feature is missing from the bottom corner of a DANGEROUS placard compared to other primary placards?

  • A. A hazard symbol.
  • B. A hazard class number. (correct answer)
  • C. A UN identification number.
  • D. The text identifying the material.

Why: Unlike specific hazard class placards, the DANGEROUS placard does not display a hazard class number in the bottom corner because it represents multiple mixed classes.

45. For which type of packaging must the 4-digit UN identification number be displayed on the placards or orange panels?

  • A. Only on non-bulk packages weighing less than 119 gallons.
  • B. On bulk packaging, such as cargo tanks and portable tanks. (correct answer)
  • C. On all packages regardless of size.
  • D. Only for Class 1 Explosives.

Why: Identification numbers must be displayed on bulk packaging, such as cargo tanks, portable tanks, and tube trailers.

46. Under what condition can you use a DANGEROUS placard?

  • A. When transporting any mixed load of Table 1 materials.
  • B. When transporting a single Table 2 material weighing over 5,000 pounds.
  • C. When transporting a mixed load of two or more Table 2 materials totaling 1,001 pounds or more. (correct answer)
  • D. When transporting bulk packaging containing Combustible liquids.

Why: The DANGEROUS placard may be used for a mixed load of two or more Table 2 hazard classes if the total weight is 1,001 pounds or more.

47. What is the primary difference between a hazmat label and a hazmat placard?

  • A. Labels are used for Table 1 materials; placards are for Table 2 materials.
  • B. Labels are placed on individual packages; placards are placed on the outside of the transport vehicle. (correct answer)
  • C. Labels are 9.84 inches square; placards are 4 inches square.
  • D. Labels are only required for international shipments.

Why: Hazard warning labels are affixed to individual packages, while placards are placed on the exterior of the vehicle, cargo tank, or freight container.

48. What is the driver's responsibility regarding placards before moving a loaded vehicle?

  • A. To design and print the placards.
  • B. To ensure the correct placards are securely affixed and visible on all four sides. (correct answer)
  • C. To write the UN number on the placards using a pen.
  • D. To place the placards inside the cab window.

Why: The driver must not move a vehicle requiring placards unless the correct placards are properly affixed and visible on all four sides.

49. You are transporting 500 pounds of Class 3 (Flammable Liquid). This is the only hazmat on your vehicle. What placard should you display?

  • A. FLAMMABLE.
  • B. DANGEROUS.
  • C. COMBUSTIBLE.
  • D. No placard is required. (correct answer)

Why: Class 3 is a Table 2 material. Because the total gross weight is under 1,001 pounds, no placard is required for this non-bulk shipment.

50. You are transporting a package carrying a Class 7 Radioactive label with a 'Yellow III' designation. Does the vehicle require placards?

  • A. Yes, Radioactive Yellow III is a Table 1 material requiring a placard for any amount. (correct answer)
  • B. No, unless the package weighs over 1,001 pounds.
  • C. No, only Yellow I and Yellow II require placards.
  • D. Only if the driver has a special Radioactive endorsement.

Why: Packages bearing the Radioactive Yellow III label require the vehicle to display Radioactive placards for any amount transported.

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