 The main span of the new eastbound structure, at 760 feet, is the longest box girder span in the U.S. With the completion of the new eastbound bridge and the rehabilitation of the existing bridge for westbound traffic, I-64 has at least six lanes from Charleston to Nitro.The state's long-term construction forecast, for a six-lane interstate from milepost 6 at West Huntington to Charleston and bridge replacements west of milepost 6 to the Kentucky state line will take 30 years to complete at present funding levels and cost more than $325 million.The portion from the Charleston city limits to the Kentucky state line is signed as the "Cecil H. Underwood Freeway".