It's the end stops that have the roof charger. Traffic lights would probably be too short of a stop? Unless you have plenty of them on the route so you could afford some green lights without running out of battery.

If you had charges at every stop you could just as well run cables overhead the whole route, aka a trolley bus, tram on wheels.

It'd be better if they just installed tracks and used trams. Cities like Munich have this and it's great.

Them cables are super ugly and hard to maintain. Really defeats purpose of batteries.

They're not as ugly as clouds of diesel smoke.