Instead of trams, with the necessity to spend millions on laying tracks, why are trolleybuses not preferred?
1) Takes more space - a bus by virtue of being on wheels means it needs more space. For big cities where space is limited, a light rail system saves space.
2) Safer - trolleybus requires more control from driver, and more % for accidents.
3) Less energy: Light rail has less friction than trolley bus, so it takes less energy from the grid (depending on models ofcourse).