Chicago Transit Authority, also known as CTA, is the operator of mass transit in Chicago, Illinois and some of its surrounding suburbs, including the trains of the Chicago "L" and CTA bus service. The CTA is an Illinois independent governmental agency that started operations on October 1, 1947 upon the purchase and combination of the transportation assets of the Chicago Rapid Transit Company and the Chicago Surface Lines streetcar system. In 1952, CTA purchased the assets of the Chicago Motor Coach Company, which was under the control of Yellow Cab Company founder John D. Hertz, resulting in a fully unified system. Today, the CTA is one of the three service boards financially supported by the Regional Transportation Authority. The Chicago Transit Authority provides service to Chicago and 40 surrounding suburbs. The CTA provided a total of 532 million rides in 2011, a 3 percent increase over 2010 with ridership rising to levels not seen for 20 years.