Stop! This is Private Property
If a group of people was asked to describe a stop sign, you would be very surprised at the member of the group describing a blue hexagon. That person would have everyone arguing with them that all stop signs are red. But as it turns out, many of Hawaii’s stop signs are blue.
The blue stop signs are used to differentiate certain property areas in Hawaii. In the Aloha State, most routes to commercial sites have the universal red-colored stop sign. But if you’re invited up to somebody’s private property, you’ll end up seeing blue stop signs on the way. So it appears that they might represent some type of exclusivity.