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CDL · Communication Rules

What is a placard on a hazmat vehicle?

Reviewed by Jordan Morley, Editorial Lead at 247SimpleTests. Written by the 247SimpleTests Editorial Team from the official source material cited on every question.

Correct answer

A diamond-shaped sign attached to the outside of the vehicle showing the hazard class of the cargo

  1. A A type of license plate
  2. B An optional decoration
  3. C A document that travels in the cab
  4. D A diamond-shaped sign attached to the outside of the vehicle showing the hazard class of the cargo

Why this is the answer

Placards are diamond-shaped (square turned on point) signs attached to the outside of vehicles carrying hazardous materials. They communicate the hazard class to anyone in proximity to the vehicle: other drivers, emergency responders, inspectors, and the public. Placards must be displayed on all four sides of the vehicle (front, rear, both sides), must be at least 10.75 inches square, and must be visible from the direction they face. The placard's color, symbol, and class number identify the hazard: a red flame for flammable liquids/gases, a yellow ball for oxidizers, a white skull and crossbones for poisons, etc. Most hazmat loads above 1,001 pounds require placards; some materials require placards at any quantity.
Source: FMCSA CDL Manual 9.2.4 Placards

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About this topic: Communication Rules

Communication rules cover shipping papers, placards, labels and markings: what each must show, where papers must be kept in the cab, and when placards are required. This is the most heavily tested hazmat topic. This is one of 19 Hazardous Materials questions on communication rules, each with a full explanation on a single study page.

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Related questions

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When transporting hazardous materials, where must the shipping papers be kept?

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Which of the following is required on a hazmat shipping paper?

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