I've always wondered about this.
So if you build a road in CS territory, and then later the road falls into your territory (through conquest, or by buying the CS, or through culture-bombing with a Citadel) do you then start paying maintenance on that road?
And I suppose the answer is obvious, but do you also start paying maintenance on roads other civs built if they fall into your territory for whatever reason? (conquest, peace deal, Citadel bombing)
Not true. The builder of any road segment in unowned territory pays maintenance. Just reconfirmed it by building a road segment in no-man's land. GPT drops from -1 to -2. Scrap the road and it rises to -1 gpt. Happy to post a save file, if you like.
Comically though you can pillage AI roads in unowned territory to break city connections and they don't seem to mind.
Who pays maintenance cost for roads in razed cities? There might be roads build by AI and also player might have build roads in AI territory before attacking.
Who pays maintenance cost for roads in razed cities? There might be roads build by AI and also player might have build roads in AI territory before attacking.