[1] Corridor Q does not meet any ADHS Corridors other than B, but it meets the planned Coalfields Expressway (U.S. Route 121) near Grundy, Virginia, the King Coal Highway (U.S. Route 52) in Bluefield, West Virginia, and Interstate 77 just to the east near Princeton.

The corridor is expected to continue southeastward to the Coalfields Expressway approximately five-miles from the Kentucky state line.

[3] In the early 1970s, the former Virginian Railway right-of-way along the north bank of the New River eastward from a point near the VA-WV state line near Glen Lyn to Narrows was acquired by VDOT's predecessor agency from the Norfolk and Western Railway to enable four-laning of the highway through the narrow space between the river and rocky bluffs.

Police presence along the highway is especially high in the town of Narrows, VA. (Where the speed limit is 40 miles per hour).

Future plans include converting the Smart Road into a 5.7-mile limited-access highway, connecting Blacksburg directly to I-81.

The section from the Virginia state line east to US 19/WV 112 opened in 1977 at a distance of 5.38 miles (8.66 km).

The remainder of the highway between the Interstate 77 junction and the Virginia state line at Glen Lyn opened in 1972 and 1973 (MP 15.84 to 27.06).