This is the street name signs in Songkhla Province(สงขลา), Thailand. Notice it has a mermaid as a symbol of Songkhla Province. Because the Songkhla province have a beach called Laem Samila. In The beach you can see the mermaid statue.The legend and inspiration of the mermaid there made in to the street signs symbol showed in this picture.
Every province in Thailand has a symbol seal of its own.