At one point, US 4 in Vermont was proposed to be an expressway across the state. Nowadays it dead ends at US 7 South of Rutland, across from what I'd now the Diamond Run Maul. This would have become part of the Modified Central Route of the proposed Interstate 92.

"MODIFIED" CENTRAL ROUTE: 281.6 miles from the area of Glens Falls, New York to Portland, Maine. This corridor would have required 97.1 miles of new construction and 70.2 miles of upgrading existing facilities (a 1968-1971 Interstate-quality upgrade of US 4 near Rutland, Vermont is included in this figure). Approximately 114.2 miles would have utilized already existing Interstate highways (I-89 in Vermont and New Hampshire, and I-393 in New Hampshire). The route, which was estimated to cost $346 million by the time it was completed in 1979, would have gone through Rutland and White River Junction, Vermont; Lebanon and Concord, New Hampshire; and Sanford and Portland, Maine. (An extension of the central route east to Calais, Maine was not considered for this study.)

http://www.bostonroads.com/roads/I-92