1950 – Current
The Federal-Aid Highway Act of 1956 creates the limited-access interstate system. Interstate Highways 70 and 68 are constructed, and supercede U.S. Route 40 as the primary transportation routes through the region. U.S. Route 40 is bypassed and becomes a local, secondary, alternate, or, a scenic road. The National Road was designated a National Historic Civil Engineering Landmark in 1976 and a State Heritage Park in 1994. Along the 90 miles of road in Pennsylvania, 79 sites have been deemed eligible for listing on the National Register of Historic Places. Of those, many have already been nominated.