The proposed extension evolved from the combination of Corridors 18 and 20 of the National Highway System as designated in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), but the federally recognized corridor also includes connecting and existing infrastructure, including I-94 between Chicago, Illinois, and Port Huron, Michigan, and several spurs from I-69. Among these proposed spurs are an extension of I-530 from Pine Bluff, Arkansas; an upgrade of U.S. Route 59 (US 59) from Texarkana, Texas being designated as Interstate 369; and a split in southern Texas (I-69E, I-69C, I-69W) to serve three border crossings at Brownsville, Pharr, and Laredo.
The proposed extension evolved from the combination of Corridors 18 and 20 of the National Highway System as designated in the Intermodal Surface Transportation Efficiency Act of 1991 (ISTEA), but the federally recognized corridor also includes connecting and existing infrastructure, including I-94 between Chicago, Illinois, and Port Huron, Michigan, and several spurs from I-69 Among these proposed spurs are an extension of I-530 from Pine Bluff, Arkansas; an upgrade of U.S. Route 59 (US 59) from Texarkana, Texas being designated as Interstate 369; and a split in southern Texas (I-69E, I-69C, I-69W) to serve three border crossings at Brownsville, Pharr, and Laredo.