CBenson wrote:But the MUTCD doesn't approve of BUS does it?
No, but road signs are more spacious than the Waze display. The MUTCD also forbids abbreviating "North", "South", "East", and "West" when they refer to compass direction, but we do it because it saves considerable space on the client. Better to see "Exit 234A: US-90 BUS W / Westbank" than have "Exit 234A: US-90 Business West / Westbank" be cut off on the screen.
As long as "BUS" is pronounced "business" by TTS, I don't believe it'll be confusing. "BUS" for "business" has been asked for kinda often.