In Thailand signs are taxed based on its size, text language (Thai only, No text or multilingual text and Thai text are placed lower than other languages, Multilingual text), and static/dynamic (I assume this applies to both digital and trivision).

This also not only for advertising but also normal signs like the logo of the business on buildings. You'll see most people circumvent the more expensive multilingual rate by adding small Thai text at the top of the sign.

Unrelated, but another interesting fact is that some bus stops in Bangkok are completely funded by an advertising company. Of course, they'll get the ads space for free as a result, and they only offer it in viable locations. The current governor doesn't like this idea and settle for a less fancy bus stop paid by public money.