# What does this highway sign mean?

**URL:** <https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952>\
**Category:** Factual Questions\
**Created:** [December 31, 2003, 3:25pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952 "2003-12-31T15:25:51Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![The\_Chao\_Goes\_Mu](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_chao_goes_mu/32/3191_2.png) [@The\_Chao\_Goes\_Mu](https://boards.straightdope.com/u/The_Chao_Goes_Mu)\
**Post date:** [December 31, 2003, 3:25pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/1 "2003-12-31T15:25:51Z")

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I was driving along I-90 between Buffalo, Ny and Cleveland, OH when I say these signs along the highway and I have no clue as to what they mean.

The sign looks like a “NO PARKING” sign except instead of a “P”  
with the red slash of forboding there are the letters “HC”  
What is this “HC” and why is it forbidden?

Help before I yank out my hair!

Thanks!

C

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**Author:** ![Athena](https://avatars.discourse-cdn.com/v4/letter/a/35a633/32.png) [@Athena](https://boards.straightdope.com/u/Athena)\
**Post date:** [December 31, 2003, 3:31pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/2 "2003-12-31T15:31:59Z")

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IIRC, HC = highly combustible. I’ve seen these signs before tunnels where trucks carrying combustible materials are not permitted to enter.

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**Author:** ![toadspittle](https://avatars.discourse-cdn.com/v4/letter/t/c0e974/32.png) [@toadspittle](https://boards.straightdope.com/u/toadspittle)\
**Post date:** [December 31, 2003, 3:32pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/3 "2003-12-31T15:32:00Z")

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No Hazardous Cargo.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [December 31, 2003, 3:32pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/4 "2003-12-31T15:32:47Z")

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I believe it means No Hazardous Cargo.

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**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\
**Post date:** [December 31, 2003, 3:34pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/5 "2003-12-31T15:34:52Z")

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From [here](http://www.gribblenation.com/ohpics/gallery/):

> [@](#):
>
> No ‘HC’ and ‘HC’ signs are comon practice in Ohio cities prohibiting or allowing trucks with hazardous materials on specific highways.

Stands for “Hazardous Chemicals”.

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**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\
**Post date:** [December 31, 2003, 3:36pm UTC](https://boards.straightdope.com/t/what-does-this-highway-sign-mean/221952/6 "2003-12-31T15:36:03Z")

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_sigh_ Or “Hazardous Cargo”. Sorry, I’m posting while waiting to catch a plane home. 🙂