As a proponent of free markets, the hardest questions I’ve been faced with deal with city planning, etc., what is the free market approach to urban planning since these things require a lot of coordination and limited space (i.e. we can’t realistically have 15 subway systems or private roadways in the same city)?
Maybe we have competing cities. In an anarchist society, there is no reason why there could not be a city that is centrally planned and residents enter into voluntary contracts to pay monthly fees to a central planner to plan these kinds of things. As long as the planner does not use some kind of force to gather fees (practically taxes) on people who have not entered into these voluntary contracts it would be perfectly compatible.
That being said, in a non planned city, you might not have competing roads, but various forms of transportation would compete with each other. You might have subway systems competing with the roads competing with dedicated bus routes competing with various raised monorail systems competing with things we might not have ever thought of.
Who is to decide that we can’t have 15 subway systems? If an additional subway system is a bad idea, those who attempt to build it will lose vast amounts of money. If it is true that an additional subway system is a bad idea, nobody will attempt to buil,d one in the first place.