Amends the Intermodal Surface Transportation Efficiency Act of 1991 to include U.S. Route 83 from U.S. Route 281 to U.S. Route 77 as part of the high priority Lower Rio Grande Valley Corridor of the National Highway System in Texas. Declares that the requirement of connection to an existing Interstate System segment shall not apply to segments of the Lower Rio Grande Valley Corridor or to the U.S. Route 59 Corridor from Laredo through Houston to near Texarkana, Texas.