Placement of Placards
Pipeline and Hazardous Materials Safety Administration · Mar 21, 2000 · Reference No. 99-0282
Interprets: 49 CFR § 172.516
Reggie’s quick take
A trucking company asked whether a placard mounted under a trailer bed, behind the rear underride guard, meets the rules. The agency said no. A placard there is hard to see, and water and road debris can hit it. The agency also said a placard on a rear door painted with advertising must sit away from that artwork, and it needs a contrasting background or a contrasting border. The rules cited are § 172.516(c)(4) and (7).
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your letter and subsequent telephone conversations with Michael Johnsen of my staff concerning the placement of placards on a vehicle under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180).
You provided a description and photograph of a placard holder under the bed of a trailer, mounted behind the rear-under-ride protection device. The rear door of the trailer is painted with an elaborate advertising design. You ask if the location of a placard, as described and shown in the photograph, is in compliance with the HMR.
It is the opinion of this Office that a placard located below the bed of a trailer and behind a rear underride protection device significantly reduces the visibility of the placard and allows water, dirt, and other debris to be directed onto the placard. Display of a placard in such a location does not comply with the provisions in § 172.516. Additionally, if a placard is displayed on the rear door of the vehicle in the photograph, the placard must be displayed away from any marking (including advertising) that could substantially reduce its effectiveness. The placard must also be affixed to a background of contrasting color, or must have a dotted or solid line outer border which contrasts with the background color (see § 172.516(c)(4) and (7)). This response has been coordinated with the Federal Motor Carrier Safety Administration Hazardous Materials Unit.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.