Several
Congressional High Priority Corridors have been designated as future parts of the Interstate Highway System by the
Intermodal Surface Transportation Efficiency Act (ISTEA) in 1991 and amendments to Section 1105. By law, they will become interstates when built to
Interstate standards and connected to other interstates.
Interstate 3 Interstate 3 is the proposed designation of an Interstate Highway Corridor under development in the
Southeastern United States. It is planned to run from
Savannah, Georgia, to
Knoxville, Tennessee. Its number does not follow standard numbering conventions; under established numbering conventions, I-3 would normally run west of I-5 along the
Pacific Coast. The unnumbered Interstate was established by the
Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) legislation that also provided for
Interstate 14. The "Interstate 3" designation has not been officially accepted by
American Association of State Highway and Transportation Officials (AASHTO) or the
Federal Highway Administration (FHWA), but is being used by the
Georgia Department of Transportation and others to identify the highway. The number comes from the
3rd Infantry Division, which is based in Georgia. The exact route has not been finalized.
Interstate 7 or 9 Interstate 7 or 9 has been proposed by
Caltrans for
State Route 99 in central
California. It would go from the split with
I-5 at
Wheeler Ridge (
Wheeler Ridge Interchange) north through
Bakersfield and
Fresno to
Stockton, where the proposed route(s) turns west via the
SR 4 freeway to a terminus at I-5 in the central part of that city. An alternate proposed terminus is located at the I-5/
US 50/
Capital City Freeway junction in
Sacramento, where the future Interstate(s), after continuing north from Stockton along Route 99, can turn west along the
Capital City Freeway, already an Interstate route (unsigned I-305), to connect with I-5, which extends north toward
Redding. This also serves as a connector to the existing northern portion of Highway 99. The future Interstate's prospects for development to appropriate standards are tied to the Caltrans "Route 99 Corridor Enhancement Master Plan"; this document posits that when and if Interstate status is conferred, the route will be designated I-7 or I-9. The route is to remain roughly
parallel to I-5, serving major cities in California I-5 does not, including Fresno and Bakersfield. In August 2005, with the passage of that year's SAFETEA-LU federal transportation legislation, SR 99 from Wheeler Ridge to Stockton and beyond to Sacramento was designated as
High Priority Corridor 54, the California Farm-to-Market Corridor; this legislation also designated that corridor as a future segment of the Interstate System.
Interstate 42 (Oklahoma–Arkansas) On May 20, 2021, Senator
Jim Inhofe, of Oklahoma, introduced legislation to designate the portion of US 412 between I-35 in Noble County and
I-49 in
Springdale, Arkansas as future Interstate 42 (I-42). The bill, titled the "Future Interstate in Oklahoma and Arkansas Act" (), was cosponsored by senators
John Boozman and
Tom Cotton, both of Arkansas. The senators' stated reasons for seeking an Interstate designation along
US 412 included encouraging economic development, expanding opportunities for employment in the region, making travel safer and shipping easier, attracting new businesses, and better connecting rural and urban communities. Other supporters of the measure include Mayor
G. T. Bynum of Tulsa, and the heads of both ODOT and the
Arkansas Department of Transportation (ArDOT). The language of the bill was later included in the
Infrastructure Investment and Jobs Act (). Interstate 42 (I-42) was the proposed designation but was withdrawn. ArDOT and ODOT later resubmitted the application to the Spring 2024 meeting; AASHTO approved the route as Interstate 42, conditional on it being upgraded to
Interstate standards.
Interstate 67 }} Interstate 67 has been a proposed number for at least three highways. I-67 was originally the designation given to a never-built highway connecting
Kalamazoo, Michigan, to the east side of
Elkhart, Indiana, as part of the original Interstate numbering plan in 1957. A planning map shows a freeway along this routing intersecting the
Indiana Toll Road just west of the
State Road 19 interchange. The
Michigan State Highway Department officially requested switching the I-67 designation to a route from Benton Harbor to Grand Rapids in 1958, and in the process proposed the northerly extension of the original I-69 from the I-80/I-90/Indiana Toll Road to Lansing. The I-67 designation was denied by the
American Association of State Highway and Transportation Officials which then assigned I-196 to the Benton Harbor to Grand Rapids route, west of the
I-96 junction near
Grand Rapids.
Indiana has proposed using the I-67 designation for the freeway upgrade of
US 31 currently under construction between
Indianapolis and
South Bend, possibly continuing northward via the US 31 freeway to
Benton Harbor, Michigan, and going northward from there along existing
I-196 to
Grand Rapids. The Indiana Senate unanimously passed a resolution calling for federal funding for this proposal and the I-67 designation in 2003. Meanwhile, Indiana expedited the upgrading of three major sections on US 31 between Indianapolis and South Bend including the Kokomo Bypass. This was done using funds received through the 2006 Major Moves deal. Such a proposal would put I-67 in the proper place in the grid (it is the only number available for that route). A third, much shorter, proposal in 2011 by the I-67 Development Corporation from the
Owensboro, Kentucky, area involves continuing the proposed I-67 in Indiana along a route parallel to
US 231 from
Crane, Indiana, to
Bowling Green, Kentucky. Much of the proposed route already exists and is close to Interstate grade. Only the northern third from
Dale, Indiana, to Crane remains unfinished. It would use the
Natcher Bridge to cross the
Ohio River, Kentucky's
I-165 and Indiana's Lincoln Parkway, an expressway facility that would need to be fully upgraded to Interstate standards. It would go around the cities of
Jasper and
Huntingburg in Indiana as well as Owensboro,
Hartford, and
Morgantown, Kentucky, and end at Bowling Green. It could also be linked to the first proposal by overlapping I-67 with the currently under construction I-69 from Indianapolis to Crane. ==Future Auxiliary Interstate Highways==