It is a portion of the old route of U.S. Highway 75 along the South Central Expressway in the southeastern part of Dallas that Interstate 45 and U.S. Highway 175 did not wholly supplant altogether .
The South Central Expressway now ends in downtown Dallas .
It is a portion of the old route of U.S. Highway 75 along the South Central Expressway , which now ends in downtown Dallas , in the southeastern part of Dallas that Interstate 45 and U.S. Highway 175 did not wholly supplant altogether .