In 1964, the President's Appalachian Regional Commission (PARC) reported to Congress that economic growth in Appalachia would not be possible until the region's isolation had been overcome. Because the cost of building highways through Appalachia's mountainous terrain was high, the region's local residents had never been served by adequate roads. The existing network of narrow, winding, two-lane roads, snaking through narrow stream valleys or over mountaintops, was slow to drive, unsafe, and in many places worn out. The nation's Interstate Highway System, though extensive through the region, was designed to serve cross-country traffic rather than local residents.
The PARC report and the Appalachian governors placed top priority on a modern highway system as the key to economic development. As a result, Congress authorized the construction of the Appalachian Development Highway System (ADHS) in the Appalachian Development Act of 1965. The ADHS was designed to generate economic development in previously isolated areas, supplement the interstate system, and provide access to areas within the region as well as to markets in the rest of the nation. The system has served its intended purpose to varying degrees of success.
Currently, the ADHS is authorized at 3,090 miles (4,970 km), including 65 miles (105 km) added in January 2004 by Public Law 108-199. By the end of FY 2004, 2,627 miles (4,228 km)—approximately 85 percent of the 3,090 miles (4,970 km) authorized—were complete or under construction. Many of the remaining miles will be among the most expensive to build.
Corridor A-1 uses US 19/SR 400 from the point that Corridor A leaves it, at SR 141 near Cumming, northeast to SR 53 near Bright. SR 400 continues northeast as a four-lane highway from SR 53 to SR 60 south of Dahlonega; this section was built "with APL funds as a local access road".
Corridor B-1 travels from KY 10 to the north end of the Portsmouth Bypass. In Kentucky, it follows US 23 and US 23 Truck; after crossing the two-lane Carl Perkins Bridge into Ohio, it uses current and planned SR 852—a western bypass of Portsmouth—and US 23. Corridors B and B-1 both end near Lucasville, where Corridor C continues north along US 23 to Columbus.
Interstate 68 (I-68) is a 112.6-mile (181.2 km) Interstate highway in the U.S. states of West Virginia and Maryland, connecting I-79 in Morgantown to I-70 in Hancock. I-68 is also Corridor E of the Appalachian Development Highway System. From 1965 until the freeway's construction was completed in 1991, it was designated as U.S. Route 48 (US 48). In Maryland, the highway is known as the National Freeway, an homage to the historic National Road, which I-68 parallels between Keysers Ridge and Hancock. The freeway mainly spans rural areas, and crosses numerous mountain ridges along its route. A road cut constructed for it through Sideling Hill exposed geological features of the mountain and has become a tourist attraction.
The construction of I-68 began in 1965 and lasted for about 25 years, being completed on August 2, 1991. While the road was being built, it was predicted that the completion of the road would improve the economic situation along the corridor. The two largest cities connected by the highway are Morgantown and Cumberland, both with populations of fewer than 30,000 people. Despite the fact that the freeway serves no large metropolitan areas, I-68 provides a major transportation route in western Maryland and northern West Virginia and also provides an alternative to the Pennsylvania Turnpike for westbound traffic from Washington, D.C. and Baltimore.
Corridor H is a highway in the U.S. states of West Virginia and Virginia. It travels from Weston, West Virginia to Strasburg, Virginia. In December 1999, a settlement agreement was reached, providing the framework for resumption of final design, right-of-way acquisition and construction activities on the Corridor H highway project. Corridor H is the only corridor highway that remains incomplete in the State of West Virginia. It begins at I-79 in Weston and will end at I-81 in Strasburg when complete. Virginia's portion of Corridor H runs from the West Virginia state line to I-81 at Strasburg, Virginia. The building of Corridor H was controversial, arousing strong passions for and against. Decades of public debate and legal battles aired the essential question of whether previously isolated areas should be preserved or opened to development. Despite the controversy, about 75 percent of the highway had been completed as of 2013. The highway is open from the Weston exit of I-79 to Kerens, Randolph County and an additional section of the four-lane is open from the Grant -Tucker, County line to Wardensville as of July, 2016.
Corridor J-1 uses SR 56 and SR 53 from Algood to Celina, via Gainesboro; it is also proposed that the entire corridor be renumbered as SR 451. The corridor serves as an alternate route for Corridor J, avoiding Livingston. The entire route is two-lane with wide shoulders, allowing for possible expansion if needed.
There are two gaps in the corridor, one in each state. The 20.1-mile (32.3 km) gap in Tennessee is located near Ocoee River to Ducktown. Plans outline a new alternate route for this section since the current route does not meet the purpose and need to support the regional transportation goals of a safe, reliable and efficient east-west route. Currently in environmental study, a record of decision is expected in 2017. The 27.1-mile (43.6 km) gap in North Carolina is located from Andrews to Stecoah. Broken in three projects, the plan outlines a new four-lane expressway that will bypass north of the Nantahala Gorge and connect Robbinsville. At a total cost to NCDOT estimated at $443 million, it is currently in reprioritization.
Since the corridor's establishment, the first major improvement for the corridor happened in 1979, when bypasses were completed for Murphy and Andrews. In 1986, US 74 was extended west from Asheville, overlapping all of Corridor K. Its last major improvement was in 2005, with the widening of NC 28 at Stecoah, first completed section Nantahala Gorge bypass. Now at 74.8% of the corridor completed, it features four-lane divided highway predominantly expressway grade, with sections in and around Cleveland, Cherokee and Dillsboro at freeway grade. The corridor also connects the cities of Ducktown and Bryson City, and features the Ocoee National Forest Scenic Byway, in Tennessee, and the Nantahala Byway, in North Carolina; treating travelers with grand vistas and various recreational activities.
Originally, this corridor was built as a four-lane divided highway for only the portion south of US 60; however, the large amount of traffic (as part of the direct route from the cities of Toronto, Buffalo, and Pittsburgh to Florida) forced the state to rethink this plan and upgrade the northern half to four lanes as well.
High vehicle accident rates and potential revenues led to strict enforcement of traffic speed limits.
A widening project is also underway on Alabama State Route 24 (SR-24) between Red Bay and Russellville, as this section of Corridor V was previously reconstructed as an improved two-lane route within divided a four-lane right-of-way.
^Special Committee on U.S. Route Numbering (June 9, 1986). "Route Numbering Committee Agenda"(PDF) (Report). State College, PA: American Association of State Highway and Transportation Officials. p. 3 – via Wikimedia Commons.