> On a side note we should drop the public bit of this because it implies a bus is “publicly funded” but highways aren’t. Both are subsidized by the taxpayer.

Arguably, neither of them should be. Give poor people money, instead of giving free highway access (and bus transit) to rich and poor alike. Rich people don't need our help, and poor people would rather have the money to spend as they wish instead of other people deciding for them what alms they should consume.

Individual cars have worse externalities than busses, so that means we should tax them more than busses. Though I suspect once drivers of cars and busses are paying non-subsidised prices for road access and fuel, busses will naturally look better in comparison, no extra tax differential needed.

It distinguishes it from private transit like Uber and taxis and even shared ride vans.