Blue stop signs are unofficial and are not issued by the U.S. Department of Transportation. They’re usually found on private property, especially in Hawaii. Although they’re blue, they still mean you should stop, just like a red stop sign. They’re often placed by property owners, like on estates or private roads.

Even though they aren’t legally recognized for public roads, it’s important to stop at blue signs to avoid potential citations. Outside the U.S., blue stop signs may indicate restricted areas rather than a simple stop.

Around the world, you might also come across other unusual road signs, like those warning of kangaroos in Australia or toads crossing in the UK. These unique signs help with local safety and culture.