Riverside and Artesia Freeway (SR 91) and the Garden Grove Freeway (SR 22) running east–west, and the Orange Freeway (SR 57), the Costa Mesa Freeway (SR 55), the Laguna Freeway (SR 133), the San Joaquin Transportation Corridor (SR 73), the Eastern Transportation Corridor (SR 261, SR 133, SR 241), and the Foothill Transportation Corridor (SR 241) running north–south. Minor stub freeways include the Richard M. Nixon Freeway (SR 90), also known as Imperial Highway, and the southern terminus of Pacific Coast Highway (SR 1). There are no U.S. Highways in Orange County, though two existed in the county until the mid-1960s: 91 and 101. US 91 went through what is now the state route of the same number, and US 101 was replaced by Interstate 5. SR 1 was once a bypass of US 101 (Route 101A). Interstate 5 Interstate 405 Interstate 605 State Route 1 State Route 22 State Route 39 State Route 55 State Route 57 State Route 72 State Route 73 State Route 74 State Route 90 State Route 91 State Route 133 State Route 142 State Route 241 State Route 261 Bus The bus network comprises 6,542 stops on 77 lines, running along most major streets, and accounts for 210,000 boardings a day. The fleet of 817 buses is gradually being replaced by CNG (Compressed natural gas)-powered vehicles, which already represent over 40% of the total fleet. Service is operated by OCTA employees and First Transit under contract. OCTA operates one bus rapid transit service, Bravo, on Harbor Boulevard. In addition, OCTA offers paratransit service for the disabled (OC ACCESS), also operated by MV. Rail Since 1992, Metrolink has operated three commuter rail lines through Orange County, and has also maintained Rail-to-Rail service with parallel Amtrak service. On a typical weekday, over 40 trains run along the Orange County Line, the 91 Line and the Inland Empire–Orange County Line. Along with Metrolink riders on parallel Amtrak lines, these lines generate approximately 15,000 boardings per weekday. Metrolink also began offering weekend service on the Orange County Line and the Inland Empire-Orange County line in the summer of 2006. As ridership has steadily increased in the region, new stations have opened at Anaheim Canyon, Buena Park, Tustin, and Laguna Niguel/Mission Viejo. Plans for a future station in Placentia are underway and is expected to be completed by 2020. Since 1938, the Atchison, Topeka, and Santa Fe Railroad and