A trolleybus is a public transport bus, usually a city bus, but sometimes a regional transit bus, powered by electricity from overhead cables that is transferred to the bus by trolley poles.
As opposed to a tram which has metal wheels running on rails, the trolleybus has rubber tyres and runs on a conventional road surface. Trolleybuses are normally manually guided along the roadway by use of a human driver and steering wheel (although there are a small number of automatic guidance systems operating in a few locations).
In the US, an imitation cable car, fitted on a bus chassis, is often also referred to as a trolleybus. Because it is built for a very specific purpose -to take tourists for a ride- we refer to it as a special.
See all bus type definitions.