Earlier quoted context omitted.
I expected to see better performance from the bus, but it is surprisingly poor: https://ourworldindata.org/travel-carbon-footprint Haven't dug into their sources, but I assume this is because buses often run with low utilization. Anyway the answer is trains, the answer is always trains in public transit.
Trains are a tough sell, at least in the western US. So much wide open space, trains are slow, high speed trains too expensive to justify given the sparse population. I remember once doing the math and finding that there are many times when our local light rail is less efficient than just putting four people in a sedan. When the train is full, though, it's unbeatable. EVs throw another wrench into that math since the…
Switzerland has a low population and is covered in trains