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AARoads Forum

National Boards => General Highway Talk => Traffic Control => Topic started by: Pink Jazz on July 02, 2015, 11:56:58 PM

Title: Hazmat signs - "HC" vs. "HM"
Post by: Pink Jazz on July 02, 2015, 11:56:58 PM
I have noticed that here in the Phoenix area, some of the older signs with the legend "HC" (for Hazardous Cargo) in a green circle or crossed red circle have now been replaced by new signs with the legend "HM" (for Hazardous Materials).

I wonder, is this also occurring elsewhere?  Does the MUTCD prescribe "HM" over "HC"?  If so, is there any reason why "HM" would be preferable?
Title: Re: Hazmat signs - "HC" vs. "HM"
Post by: Greybear on July 03, 2015, 01:31:52 AM
I've seen that same switch from "HC" to "HM" in the Dallas-Ft Worth area as well.
Title: Re: Hazmat signs - "HC" vs. "HM"
Post by: vtk on July 03, 2015, 05:32:26 AM
This change has also been observed in Columbus.

Anyone sufficiently unlazy to look for this in MUTCD or other policy documents?
Title: Re: Hazmat signs - "HC" vs. "HM"
Post by: roadman on July 03, 2015, 08:00:57 AM
The change from HC to HM on the R13 series Hazmat markers was made in the 2003 MUTCD.  It appears the change was made to bring signing into conformance with industry standard terminology, which is Hazardous Materials - not Hazardous Cargoes.
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