The arrival of Metro light rail comes approximately sixty years after the previous streetcar system was shut down, which left Houston as the largest city in the United States without a rail system since 1990, when Los Angeles' Blue Line opened. Metro opened two additional light rail lines in 2015, the Purple (Southeast) and Green (East End) Lines. Destinations served by these new lines include Texas Southern University, the University of Houston, BBVA Compass Stadium, and the Theater District. These new lines added another 9.9 miles of light rail. In total, Metro operates 22.7 miles of light rail service. Metro will reach approximately 18.6 million light rail boardings in FY17. Two other lines were to be completed by 2012, but funding issues dropped the number to the northern extension of the Red Line and two of the original four new lines. The extension of the Red Line was opened on December 21, 2013 and the East End/Green Line opened on May 23, 2015. Due to federal investigations and the lack of funds, the plans may degenerate further. Three of the five lines were previously going to be bus-rapid transit, but due to high ridership possibilities, the decision was made to make them all light rail. Additional rail will be laid as approved by a 52% yes to 48% no margin in the November 2003 election. Critics have alleged the existence of a conflict of interest in the planned expansion. Major contractors including Siemens AG, which constructs the train vehicles, contributed substantial amounts of money to the Political Action Committee promoting the expansion referendum. Supporters of an expanded rail system in Houston have leveled similar charges against opponents of the referendum, noting that suburban development interests largely bankrolled the PAC opposing the referendum. In June 2005, Metro announced a revised plan for expansion of the METRORail system. The plan included four new corridors, consisting of both light rail and bus rapid transit. The bus rapid transit lines would have later been converted into light rail when ridership warranted the conversion. On October 18, 2007, the plan was revised to allow for the possibility of more federal funding. Metro decided to have all the lines consist of light rail from the start. The planned expansions are within the city of Houston and will eventually reach the two major Houston airports, George Bush Intercontinental Airport and William P. Hobby Airport. Metro is planning service to suburbs in Houston, as well as other parts of Houston. Alternatives Analysis and Draft Environmental Impact Analysis studies are currently underway on four extensions. Metro is also planning a commuter rail system in conjunction with the light rail system, pending feasibility of the plan.