> The opposite is occurring in places like Seattle. The overhead electric trolley lines are coming down as batteries become good enough to support electric buses without the PITA of going off line (electric was already needed for many routes in Seattle because of hills).

A good option (which is being implemented in Lyon) is IMC buses, battery-supplemented trolleys (or electric buses with pantographs): they can go off-grid for segments where the grid hasn't been built (not enough traffic or whatever) and it allows for spot-charging at bus stops.

Ya, the new first hill trolley is sort of like that already.

Seattle used to have a lot of dual electric diesel buses that would be diesel outside of the downtown bus tunnel and then catch onto overhead lines before entering the tunnel. However, this didn’t really work out very well (hooking up to overhead wires was error prone). They just use NG buses these days

What route has been de-eletrified? IIRC Seattle made a big push to invest in the overhead catenary system just a few years ago, as the neighborhoods that have overhead catenary wires were in a frenzy over the mere suggestion that they'd be retired.

The overhead lines do force King County Metro to avoid changing routes (a boon for local riders), and are 50% faster at getting the bus up to speed after a stop. Short of something wrecking the overhead lines on most of a route, I doubt they'll be retired soon.

Ya, I thought they were moving away from it, but it turns out they are improving overhead lines by combining it with battery tech to allow for better performance (less chance of unhooking at greater speeds using batteries to fill in gaps at intersections). See the new first hill street car: https://sdotblog.seattle.gov/2015/05/04/first-hill-street-ca...