South Texas is not only going to get its first interstate - it is also going to get a second and a third. State transportation officials knew one of three southern highways - U.S. Highway 281 in Hidalgo County, U.S. Highway 77 in Cameron County or U.S. Highway 59 in Webb County - would eventually become part of an interstate stretching from the Texas-Mexico border to Texarkana, in the northeast part of the state. Only Webb County is currently served by an interstate. The state's Trans-Texas Corridor plan calls for an Interstate 69 extension linking South Texas to points north,...