I think you'd be surprised. Look at the difference in cost per passenger mile.
I guess you're comparing the total cost of trains vs a subset of costs of cars, as is usual. Road use and pollution are free externalities after all.
As soon as a mode of transport actually has to compete in a market for scarce & valuable land to operate on, trains and other forms of transit (publicly or privately owned) win every time.
Source? The biggest source of environmental issues from EVs, tire wear from a heavier vehicle, absolutely applies to AVs. VC subsidizing low prices only to hike them later isn't exactly "without subsidy" - we pay for it either way
Where trains work they are great. Where they don't, driverless electric cars seem like a great option.
https://csh.ac.at/news/over-half-of-global-commutes-are-by-c...
Is there a magic road wand?
Roads are subsidized, free parking (and generally a lot of paid parking) is subsidized, and the sprawl encouraged by car dependence combined with the resulting infrastructure costs has and will continue to bankrupt cities.
I don't think we should "just only have trains", but the current US transit landscape is absurdly stupid and inefficient.
sure, a private vehicle is better for me, but a train is better for the world