Bucharest has the largest transport network in Romania, and one of the largest in Europe. The Bucharest transport network is made up of a metro network and a surface transport network. Although there are multiple connection points, the two systems operate independently of each other, are run by different organisations (the metro is run by Metrorex and the surface transport network by Societatea de Transport București. The two companies used separate ticketing systems until 2021, when a new smartcard was introduced alongside the old tickets, which allows travel on both the STB and the Underground. Bucharest Metro Bucharest has a fairly extensive metro system consisting of five lines (M1, M2, M3, M4, and M5) run by Metrorex. In total, the network is long and has 63 stations, with average distance between stops. It is one of the fastest ways to get around the city. Surface transport Surface transport in Bucharest is run by Societatea de Transport București (STB) and consists of an extensive network of buses, trolleybuses, trams and light rail. The STB network is one of the densest in Europe, and the fourth largest on the continent, carrying about 1.7 million passengers daily on 85 bus lines, 23 tram lines, 2 light rail lines and 15 trolleybus lines. At times, however, it suffers from severe overcrowding. STB is a reasonably efficient and a very frequently-used way of getting around Bucharest. As with the Metro, the system is undergoing a period of renewal. Some new features are the upgrade of tram/trolleybus infrastructure and the replacement of old rolling stock. Buses With a total route length of , the STB bus network is the densest of all the transport types in Bucharest. There are 85 bus lines (plus 25 night routes) operating mostly in the municipality of Bucharest, as well as 27 bus lines serving commuters from surrounding towns and villages in Ilfov County. In mid-2005, the lines that linked the city to the peripheral area were licensed out to independent transportation providers, but in early 2006, they were returned to STB control due to a wide range customer complaints about the private operators. Sometime in 2010, all the STB lines of the peripheral network were removed, leading to an increase in minivans owned by private transport companies, and so far only a few of these lines have been put back. Fleet STB's bus fleet is made up of 1,143 vehicles