# Identification number display on placards.

- **operation:** document
- **citation:** 49 CFR 172.503
- **title:** Identification number display on placards.
- **source type:** regulation
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** 2026-08-18
- **summary:** For procedures and limitations pertaining to the display of identification numbers on placards, see § 172.334.

[Amdt. 172-58, 45 FR 34701, May 22, 1980]
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/49-cfr-172-503.json
- **markdown:** https://regulus.evalyn.ai/document/49-cfr-172-503.md
- **app url:** https://regulus.evalyn.ai/document/49-cfr-172-503
- **source url:** https://www.ecfr.gov/on/2026-08-18/title-49/section-172.503
**body:**

For procedures and limitations pertaining to the display of identification numbers on placards, see § 172.334.

[Amdt. 172-58, 45 FR 34701, May 22, 1980]
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- **body characters:** 153