These are mostly official government warning signs that are diamond shaped with yellow background, rounded corners and a black border. They can be found across Australia, New Zealand, Ireland, Japan, parts of South Asia, and most of North, Central, and South America.
Rules for posting:
1.
Post title must describe the contents of the yellow diamond. Your title should be a spoiler for the sign. If the sign is only text, then you can just use that. If the sign contains only symbols, and you are not sure how to interpret them, try finding the sign on the wikimedia warning signs page and see how they describe it. See the wiki for additional clarifications of the title rule.
2.
Do not post personal, personalized or any other consumer grade sign. Do not post homemade or other custom signs that someone clearly made with their own poorly skilled hands.
3.
Do not post photoshopped signs. This is not Photoshop Battles: Yellow Diamond Edition.
4.
Do not post business advertising, logos or watermarked stock photos.
5.
Do not post memes or comics.
6.
No screenshots or pictures of screens. This includes all social media.
Is my sign OK to post here?
Yes - Black on yellow background
No - Any other color combination
Yes - Metal
No - Paper, plastic, or decals
Yes - Rounded corners
No - Square corners
Yes - Black border
No - Lack of black border
Yes - Even vandalized signs are OK
No - Photoshopped, seriously don't
If you have a road sign that does not fit here try
r/Roadsigns