That's a good question, but you also have to take into account that passengers also pay transit fares, which can sometimes cost as much as a car. I expect that mass transit would still be significantly cheaper for most people though, if there was a proper mass transit network in place.
Despite being a huge fan of public transit, I actually think the efficiency numbers would probably still come out in favor of cars, in America, in the near term. Our country has been car focused for a hundred years and the assumption of car travel is baked into the way our cities (and especially suburbs) are designed. There would need to be years of shifting urban planning before mass transit really won everywhere.
Amtrak is long haul, not "mass transit network", outside of the NE corridor which is a very special case in Amtrak.
Having a cheap enough car and expensive enough transit bill to exceed it is an extreme statistical outlier. I saw this as an owner of a cheap car and an expensive commuter rail pass.
>but you also have to take into account that passengers also pay transit fares
But that's part of why he excluded expenditures covered by the gas tax on the road comparison, you'd want to add that back in if you are adding in fares.
