Regulators get to determine what counts as a road and what is "just a trail" (it can be an important legal distinction), and they get to determine whether a particular road is public (even if it crosses private property), and in many places worldwide that official road map data is available from the government.
If that has been done, then it simplifies the dispute as you can objectively verify whether the complaint matches the official data and Google should not be routing cars there, or if the maps are correct and the appropriate solution would not involve Google - e.g. if a road is physically impassable then complaints to whoever is responsible for maintaining that road; if there are barriers or "do not enter" signs on a legally public road, then complaints to the authorities to remove these barriers and punish whoever put them up, if a path is marked public but you think it shouldn't be then legal action to try and correct it (which may or may not succeed), etc.
A very flippant "HN techbro libertarian" response. Pretty much everything that is not constitutionally protected as a right can be regulated, why would you possibly think that it couldn't?
Yes, you absolutely could lobby for someone to write a law requiring Google to respond to nuisance requests from their navigation services. That is basically what DMCA does, after all.
Hypothetical example law: OK, you have a good-faith presumption up until someone emails you a copy of a deed and proves it's their driveway, then you legally need to correct it within X days or penalties start to rack up.
You've said that stuff which isn't constitutionally protected _can_ be regulated, but the question posed was _are_ maps regulated. Are they? What legal obligation to accuracy or comprehensiveness are map-makers bound by?
And are maps constitutionally protected? If political donations are speech then maps certainly seem like speech.
