 On October 1, 1964, I-20 was rerouted so that it followed I-35W through Fort Worth (it still followed I-35E through Dallas).By 1967, the highway was complete from the Louisiana border to the western side of Fort Worth on a route to the south of US 80, with slower construction in the lesser populated areas of West Texas concurrent with US 80.On December 2, 1971, I-20 was rerouted across the southern side of the Dallas/Fort Worth Metroplex, with the old section through downtown Dallas and Fort Worth being redesignated as Interstate 30.