Trolleybuses draw power from overhead wires and use rubber tires which makes them incredibly quiet on busy city streets

A closer look

It is the unholy, silent fusion of a tram and a city bus. Trolleybuses have rubber tires so they can steer around potholes, but they drag two giant poles along an electrified overhead grid like an oversized slot car. Because they lack a massive diesel engine and don't rattle on steel rails, they sneak up on pedestrians with an eerie, whisper-quiet stealth that makes crossing the street in Eastern European cities an extreme sport.