Original sentence: Chattanooga, Tennessee operates nine free (no fares) electric buses, which have been in operation since 1992 and have carried 11.3 million passengers and covered a distance of 1.9 million miles.Rides are free as part of Adelaide's public transport system
Edited sentence: Chattanooga, Tennessee operates nine zero-fare electric buses, which have been in operation since 1992 and have carried 11.3 million passengers and covered a distance of 1.9 million miles.Rides are zero-fare as part of Adelaide's public transport system