The public transport in Sofia consists of a comprehensive network of bus, trolleybus, tram and metro lines. It is overseen by the Sofia Urban Mobility Center, a municipal enterprise responsible for route planning, scheduling, fare collection and ticket inspection. It also pays the various transport operators for their service on a per-kilometer basis. Sofia is the only city in Bulgaria that operates the four modes of public transport.[1]
The public transport in Sofia is operated by three municipal and one private company — Sofia Public Bus Transport Company JSC operates the majority of bus services; Sofia Public Electrical Transport Company JSC operates the tram and trolleybus networks; Metropoliten JSC operates the Sofia Metro; and the private company MTK Group operates some, mainly suburban, bus services.