Class 7 is rare on the highway, but it is one of the easiest placards to recognize because nothing else looks like it. Yellow on top, white on the bottom, and the three-bladed trefoil symbol that most people already associate with radiation. The detail worth knowing is how the label categories work, since they drive when a placard is required.
This is study guidance, not regulatory advice. The binding rules are in 49 CFR 172.403 and your official state CDL manual.
What the placard shows
The Class 7 placard is yellow over white, with the trefoil symbol, the word RADIOACTIVE, and the number 7 at the bottom point. The yellow-over-white split is unique, so the color pattern alone is a strong signal, as covered in hazmat placard colors explained.
The three label categories
Radioactive packages carry one of three labels, and these are different from the vehicle placard. The category reflects the radiation level at the package surface and a number called the transport index.
| Label | Category | Meaning |
|---|---|---|
| I | White | Lowest radiation level |
| II | Yellow | Moderate level, with a transport index |
| III | Yellow | Higher level, with a transport index |
The transport index is a number on the Yellow labels that helps control how packages are grouped and spaced in transport.
When the placard is required
A radioactive placard is required when the shipment includes material that carries the highest-level (Yellow-III) label, which makes it a Table 1 situation: placarded regardless of amount. This is one reason the Table 1 versus Table 2 distinction matters, and it is set out in 49 CFR 172.504. To work through the diamond itself, see how to read a hazmat placard.
Where it fits
Class 7 is one of the nine hazard classes. Because radioactive transport is tightly regulated, oversight is shared between the U.S. Department of Transportation and the Nuclear Regulatory Commission, and emergency response is covered in the PHMSA Emergency Response Guidebook. For the CDL test, focus on recognizing the yellow-over-white trefoil instantly.
Frequently asked questions
What does the Class 7 radioactive placard look like?
It is yellow on the top half and white on the bottom, with the three-bladed trefoil symbol, the word RADIOACTIVE, and the number 7 at the bottom point.
What are the radioactive label categories?
Packages carry one of three labels: I-White (lowest level), II-Yellow, and III-Yellow (higher level). The Yellow labels include a transport index that reflects the radiation level and controls package spacing.
When is a radioactive placard required?
A radioactive placard is required for shipments containing material that bears the highest-level Yellow-III label, and in that case it must be placarded in any amount, like other Table 1 materials.
What is the best way to learn the Class 7 placard?
Anchor on the unique yellow-over-white trefoil and drill it with a recognition app such as CDL Placards alongside the other classes. Your state CDL manual is the authority on the label and placarding rules.
