I know this is an older thread, but there's no possible way a US 50 ALT route will be built just north of the existing route considering all of the ROW acquisition needed from the airport and the lack of a logical place for it to reconnect with US 50 or VA 28 in the east. I also don't see a reason for such a project, considering US 50 is already a road large enough to be expanded upon. It would be better to perform a Delaware State Route 1-esque upgrade, leaving minor intersections and driveways, perhaps using some signalized green-Ts and Michigan lefts at more-important junctions, and putting a few interchanges where absolutely needed such as at Loudoun County Parkway, maybe even a few overpasses here and there. No point in building a new highway so close to a much more easily fixable existing one.