That's not really what the OP is talking about. Not sure why they aren't popular in the US, but many cities in Europe have extensive electric bus networks power

That's not really what the OP is talking about. Not sure why they aren't popular in the US, but many cities in Europe have extensive electric bus networks powered by electrical lines overhead. I suspect the benefits are you don't have to lay rail + you can use normal vehicle lanes + you get the benefits of not having a combustion engine (smog, mechanical issues, fuel storage/re-fill).