I-73

I-73
State	Multi-state
Route	73
Type	Interstate
Length mi	proposed
Length km	proposed
Established	1995 (designation)
Terminus a	South: Myrtle Beach, South Carolina
Terminus b	North: Sault Ste. Marie, Michigan (proposed)
States	South Carolina, North Carolina, Virginia, West Virginia, Ohio, Pennsylvania, Michigan

I-73 is a designated north–south Interstate Highway corridor conceived to link the Atlantic coast at Myrtle Beach with the industrial and Great Lakes regions of the northern United States, passing through major metropolitan and regional centers such as Charlotte, North Carolina, Greensboro, North Carolina, Roanoke, Virginia, Charleston, West Virginia, Columbus, Ohio, Pittsburgh, Pennsylvania, and Sault Ste. Marie, Michigan. Enacted by the United States Congress in the mid-1990s, the corridor reflects federal, state, and regional planning efforts involving agencies such as the Federal Highway Administration, state departments of transportation including the North Carolina Department of Transportation and the South Carolina Department of Transportation, and metropolitan planning organizations in the Charlotte metropolitan area and Pittsburgh metropolitan area. Implementation has produced segments, studies, and controversies across multiple jurisdictions, involving stakeholders like the American Association of State Highway and Transportation Officials, environmental groups, freight carriers, and tourism authorities.

Route description

The designated corridor alignment traverses diverse landscapes and urban contexts, beginning near Myrtle Beach and routing inland toward the Pee Dee River basin, intersecting existing routes such as U.S. Route 501, U.S. Route 74, and I-95 in the Carolinas before progressing toward the Piedmont population centers of Charlotte and Greensboro. In Virginia the corridor variants considered pass near Danville, along the foothills toward Roanoke and the Shenandoah Valley, crossing Appalachian ridgelines and connecting with highways like I-81 and I-64. Further north, proposed and existing alignments traverse the Appalachian Plateau through West Virginia near Beckley and Charleston, link to the Ohio River corridor adjacent to Huntington, West Virginia and Charleston, then follow or parallel corridors through Ohio near Columbus with interchanges to I-70 and I-71. In Pennsylvania variants approach the Pittsburgh region, connecting with I-76 and I-79, while Michigan proposals extend the corridor across the Upper Peninsula to Sault Ste. Marie, interfacing with I-75 and international crossings to Ontario. Along its course the corridor intersects rail lines such as those of Norfolk Southern Railway and CSX Transportation, port facilities including Port of Charleston (South Carolina) and Port Columbus, and military installations like Fort Bragg and Wright-Patterson Air Force Base in regional influence areas.

History

Congress established the corridor designation in the 1991 and 1995 highway authorization frameworks after regional advocacy from congressional delegations representing South Carolina, North Carolina, Virginia, and Midwestern states, building on economic development reports from organizations such as the Brookings Institution and the Economic Development Administration. Early routing studies involved state transportation planners at the North Carolina Department of Transportation and consultants allied with firms that previously worked on corridors like Interstate 95 and Interstate 77. Environmental impact assessments referenced statutes including the National Environmental Policy Act and consulted federal agencies such as the U.S. Fish and Wildlife Service and the Environmental Protection Agency. Political debates featured prominent legislators including members of the Senate Committee on Environment and Public Works and representatives from the House Committee on Transportation and Infrastructure as well as regional business coalitions and tourism bureaus in Myrtle Beach and Charlotte. Implementation produced completed segments, notably portions near Greenville, South Carolina and sections of upgraded two-lane corridors in North Carolina, while many segments remain in planning or design.

Future and proposed extensions

Future work envisions completing continuous Interstate-standard grade separations, controlled-access alignments, and upgrades to connect existing segments into a contiguous route from the Atlantic coast to the Great Lakes. State proposals include corridor upgrades in North Carolina to link Greensboro and Winston-Salem with limited-access sections, Virginia studies for Appalachian crossings evaluated by the Virginia Department of Transportation, and Ohio planning that would integrate the corridor with freight logistics networks in Columbus. Federal discretionary funding, Interstate maintenance programs, and public–private partnerships cited by the Federal Highway Administration could accelerate construction, while environmental litigation and right-of-way acquisition challenges involving stakeholders such as The Nature Conservancy and local historic preservation commissions may delay sections. Binational coordination for northern extensions would engage agencies like Transport Canada and provincial authorities in Ontario regarding crossings at Sault Ste. Marie International Bridge.

Exit list

A consolidated exit list remains provisional, as alignments vary by state and pending environmental and engineering approvals. Existing signed connections and major interchanges along constructed segments include junctions with I-95, I-40, I-85, I-77, I-81, I-64, I-70, I-71, I-76, I-79, and I-75 in their respective metropolitan regions. Local interchanges provide access to urban centers such as Myrtle Beach Convention Center, Charlotte Douglas International Airport, Greensboro Coliseum, Roanoke-Blacksburg Regional Airport, Huntington Mall, Port Columbus, and Pittsburgh International Airport. Official mileposts, ramp configurations, and exit numbering will be determined by state departments of transportation during final design.

Auxiliary routes and related corridors

Plans for auxiliary Interstate and U.S. Highway connectors contemplate beltways, spurs, and business routes to serve metropolitan areas encountered by the corridor, paralleling the model of auxiliary routes like Interstate 277 (Ohio), Interstate 277 (North Carolina), Interstate 485, and Interstate 376 as precedents. Proposed connectors would facilitate freight movement to logistics hubs including Charlotte Douglas International Airport and inland ports such as Port of Huntington-Tristate, and coordinate with multimodal corridors like the Southeast High Speed Rail Corridor and regional passenger services including Amtrak routes through the Piedmont and Carolinian services.

Traffic, usage, and safety statistics

Traffic modeling by state transportation agencies and the Federal Highway Administration estimates varying annual average daily traffic volumes along segments, with highest congestion predicted in urbanized corridors near Charlotte and Columbus and lower volumes across Appalachian and rural stretches near Beckley and northern Michigan approaches. Safety analyses reference crash data compiled by state highway safety offices and the National Highway Traffic Safety Administration, noting priorities for median barrier installations, interchange reconfigurations, and roadway lighting to reduce fatality rates found in comparable corridors such as I-77 and I-79. Freight tonnage projections from the Bureau of Transportation Statistics indicate potential shifts in truck traffic patterns contingent on corridor completion, affecting regional supply chains and port hinterlands.

Category:United States Interstate Highways