A trolleybus is a type of electric bus that draws power from dual overhead wires using spring-loaded poles. This system allows the trolleybus to operate without the need for tracks, making it flexible in urban environments. Trolleybuses are often used in cities to provide public transportation, offering a quieter and more environmentally friendly alternative to diesel buses. Trolleybuses are part of the broader category of electric public transport, which includes trams and light rail systems. They are particularly popular in cities like San Francisco and Geneva, where the infrastructure supports their operation. Their ability to reduce air pollution contributes to cleaner urban air quality.