"why not use it for work-commute" In Oslo (and I am sure other European places), the answer is simply "because I want to spend 30 minutes on my commute instead

"why not use it for work-commute" In Oslo (and I am sure other European places), the answer is simply "because I want to spend 30 minutes on my commute instead of 90 minutes". (At least for train/metro) Assuming urban areas: Roads are always congested. Building more roads/more lanes only relieves it a few years then car traffic increases until you are as congested as before. (You can find proper scientific studies of this effect -- "induced traffic") But public transport, if enough people take it, take so ridiculously many more passengers per area of road that it cuts through this effect and actually helps congestion. (Establishing a bus route may also induce more traffic, but you can add another bus much more cheaply than another road lane, and actually keep up.) This requires buses to be prioritized in traffic though (dedicated lanes), otherwise there is as you point out no reason for individuals to take public transport. Basically a reserved bus/metro lane gives you "infinite road capacity" (with the obvious caveats)