Luas is operated by Transdev, under tender from Transport Infrastructure Ireland (TII). (Prior to the later RPA merger with the National Roads Authority to form TII, the tender was originally under the defunct Railway Procurement Agency jurisdiction). The Luas was a major part of the National Transport Authority's strategy (2000–2016). Four extensions to the existing Luas lines have been completed. Construction of a extension to the Green line to the North city centre and Broombridge, which links both Green and Red lines, began in June 2013 and opened to passengers in December 2017. This is the extension route previously known officially as BXD.