Interstate 27 was not part of the original Interstate Highway System chosen in the 1950s; the spur from I-40 to Lubbock was authorized with the Federal-Aid Highway Act of 1968, which added 1500 miles (2400 km) to the system. George H. Mahon, member of the U.S. House of Representatives from 1935 to 1979 and chairman of the House Appropriations Committee after 1964, helped secure funding for the road. Texas officially designated the highway in early 1969, originally running from U.S. Highway 62 near downtown Lubbock to I-40 in Amarillo; the definition was extended south through Lubbock to the south side of the loop in early 1976. The existing freeway sections, including the Canyon Expressway, were absorbed into I-27, despite not being built to Interstate standards. New construction began in 1975, from Lubbock north to New Deal, and most of the freeway was completed in the 1980s. Two long sections of US 87 were bypassed: Happy to Canyon on December 5, 1986, and Kress to Tulia soon after; I-27 was complete north of Lubbock by 1988. Most of the Happy-Canyon bypass was built along the two-lane Farm to Market Road 1541, which now ends at exit 103 southeast of Canyon.