Ludwigshafen's public transport system is run by the VBL (Verkehrsbetriebe Ludwigshafen) and the holding companies Rhein-Neckar-Verkehr (RNV) and VRN. There is an integrated Mannheim/Ludwigshafen tramway network; four tram lines (4,6,7,8) cross the Rhine bridges between the two cities and one other line (10) runs through Ludwigshafen only. In late 2008 Line 4 was extended and replaced Line 14 (also known as "Rhein-Haardt-Bahn"). Line 4 now serves as a long-distance line, which runs from Bad Dürkheim to Ludwigshafen, Mannheim and Heddesheim. The bus network consists of about ten municipal lines and further regional lines.