The biggest problem with public transport is usually the public.
Segregated services for commuters are great, but catching a bus to shop/recreation/restaurants is miserable and restrictive.
As as aside, developing mass transit always has the problem of being at the whim of the next political goal (subsidised bus routes especially). Roads are physical easy to understand, so less subject to political vs.
Yes, roads require less 'active upkeep', an austerity government might stop funding transit but they will not close roads. However, this is more of a feature of the supposed 'independence' of car transport, not 'easy to understand'.
In addition, defunding transit would be a lot harder and weirder if it is in a form that requires actual infrastructure (metro, train, tram) rather than some stops and a schedule (bus). That's one potential reason to trust bus transit projects less.
Do keep in mind that roads aren't free after construction either; they typically require pretty significant upkeep (especially things like repaving, but also e.g. traffic signals).
I have seen many public transport systems privatised and worsened over time; since there are many ways to play with funding and quality, you can hide a whole lot of bullshit. Frequency, hours, cleaning, security, ticket price, and maintenance... It can be unclear why a service is declining or who is accountable. That's what I mean by easier to understand.
Roads are public in a way that introducing a toll on an existing road is not politically viable, and maintenance issues are easier to spot.
From my experience most people have no understanding of how road maintenance works. I can’t tell you how many times I have heard people say they refuse to pay more taxes, after all they won’t even fix the potholes in our roads!
Segregated services for commuters are great, but catching a bus to shop/recreation/restaurants is miserable and restrictive.
As as aside, developing mass transit always has the problem of being at the whim of the next political goal (subsidised bus routes especially). Roads are physical easy to understand, so less subject to political vs.