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Designations of Future Interstate Corridors

With Some Discussion of Consequences

As of October 1, 2012
Although many people think the Interstate highway system is complete and permanent, each year there are changes made to the system and also occasionally there are designations of future Interstate corridors.

This document is about designations of future Interstate corridors. This document was produced to assist FHWA Division offices and State transportation agencies in their discussions with each other and with elected officials understand the distinctive methods by which such designations occur.

There are two general paths by which highways or future highways are designated as future Interstates.

One path is the administrative path. In this case, a future Interstate corridor is designated when the Federal Highway Administration (FHWA) executes its authority under section 103(c)(4)(B) of 23 United States Code (U.S.C.) (which now contains language formerly in section 139) via the process stated in Title 23 of the Code of Federal Regulations (CFR) 470. In this case, a State (or States) requests FHWA to take a designation action, presents a case that the corridor to be designated is a logical addition to the Interstate system, demonstrates, where appropriate, coordination with other States and with Metropolitan Planning Organizations (MPOs) and makes a commitment to complete the route to an Interstate design level within 25 years i.

The other path is called the Congressional path. In this case, a future Interstate corridor is identified via statutory language primarily within the uncodified provisions of section 1105(e)(5) of the Intermodal Surface Transportation Efficiency Act (ISTEA, P.L. 102-240), as amended (in which the process stated in 23 CFR 470 generally applies). Congress occasionally amends this section in other legislation and designates either a general location or more specific corridor as a future Interstate. For some corridors, an Interstate number is assigned in the statute.

Because the two paths are different but have similarities, FHWA developed the two tables below to assist in understanding the two paths. These tables are organized to respond to typical issues that arise in designation of future Interstates and related issues.

A short summary of differences between the paths follows the two tables.

Table I.
Administrative Path: Using Procedures in title 23 U.S.C.
Issue Answer
Is the FHWA Administrator's signature required prior to being designated a future Interstate corridor? Yes
Must the FHWA make a determination that the highway or proposed highway would be a 'logical addition' to the Interstate prior to designation as a future Interstate corridor? Yes
Is a written agreement required in which the State makes a commitment to complete the future highway to Interstate Standards in 25 years? Yes ii
May Interstate shields be displayed on the highway prior to the highway being completed to Interstate standards and added to the Interstate System? No
May a State, in effect, designate the location of a designated future Interstate corridor by placing "future Interstate" on a State map or by making a public announcement. No
Is coordination with affected States required prior to requesting an Interstate route number? Yes
Must placement of Future Interstate corridor informational signs for a designated future interstate be preceded by either the conclusion of the alignment selection portion of the NEPA process or a public announcement of alignment by the State? Yes
Must wording on Future Interstate Informational signs be approved by the Division office? Yes
Must location of Future Interstate Informational signs be approved by the Division office? Yes
Must exceptions to Interstate Design standards be approved by the Division Office and the FHWA HQ? Yes
Will Designation as a Future Interstate automatically result in appropriation or allocation of additional funds? No
Subsequent to designation as a Future Interstate, construction of the highway to Interstate standards and designation as an Interstate, will the highway be eligible for Interstate Maintenance funds on projects to improve the highway? No iii
Table II.
Congressional Path: Applying Section 1105(e)(5) of ISTEA AND OTHER LAW
Issue Answer
Must the highway be designated a high priority National Highway System corridor and a future Interstate in law? Yes
Is the FHWA Administrator's signature required prior to being designated a future Interstate corridor? No
Must the FHWA make a determination that the highway or proposed highway would be a 'logical addition' to the Interstate prior to designation as a future Interstate corridor? No
Is a written agreement required in which the State makes a commitment to complete the future highway to Interstate Standards in 25 years? Not generally iv
May Interstate shields be placed on the highway prior to the highway being improved to Interstate standards and added to the Interstate System? No
May a State, in effect, designate the location of a designated future Interstate corridor by placing "future Interstate" on a State map or by making a public announcement. Depends on specificity in law v
Is coordination with affected States required prior to requesting an Interstate route number? Not if number assigned in law vi
Must placement of Future Interstate corridor informational signs for a designated future Interstate be preceded by either the conclusion of the alignment selection portion of the NEPA process or a public announcement by the State? Yes vii
Must wording on Future Interstate Informational signs be approved by the Division office? Yes
Must location of Future Interstate Informational signs be approved by the Division office? Yes
Must exceptions to Interstate Design standards be approved by the Division Office and the FHWA HQ? Yes
Will Designation as a Future Interstate automatically result in appropriation or allocation of additional funds? No
Subsequent to designation as a Future Interstate, construction of the highway to Interstate standards and designation as an Interstate, will the highway be eligible for Interstate Maintenance funds on projects to improve the highway? Generally so viii

Summary of Major Differences between the two paths to Designation as a Future Interstate

  1. In the Administrative path, the FHWA makes an administrative determination of whether the proposed highway would be a logical addition to the Interstate system. In the Congressional path, no such determination is required.
  2. In the Administrative path, the State(s) must make a commitment to complete the highway to Interstate design standards within 25 years from the designation as a future Interstate. In the Congressional path, no such commitment is required (with the exception of designation under P.L. 110-244)
  3. In the Administrative path, FHWA must designate future Interstate corridors. In the Congressional path, designations are established by law, but a more specific corridor location needs FHWA approval to determine if it is consistent with the statutory language.
  4. In the Administrative path, before FHWA designates a route as a future Interstate, the route must have an approved final environment document. In the Congressional path, designation as a future Interstate may, in some cases, precede the environmental review process. ix
  5. In the Administrative path, a route number must be approved by the FHWA. In the Congressional path, a route number may be mandated in law.

In the Administrative path, after the addition to the system, IM funds may not participate in improvement projects on the designated sections.x In the Congressional path, after the addition to the system, IM funds may participate in such projects (with the exception of designation under P.L. 110-244).


i Prior to the Safe, Accountable, Flexible, Effective and Efficient Transportation Efficiency Act: a Legacy for Users, a.k.a., SAFETEA-LU, P.L. 109-59, completion to Interstate design levels was required within 12 years of designation of a future Interstate, under section 103(c)(4)(B)(ii) of title 23 U.S.C. However, section 1106 of SAFETEA-LU increased this to 25 years.

ii See previous endnote

iii Interstates in Alaska and Puerto Rico are eligible for IM funds per title 23 U.S.C. Section 119(a)(1)(A). Note that MAP-21 eliminated the Interstate Maintenance (IM) program, so this will be a moot point once the period of availability for IM funds has expired.

iv Designations of two future KY corridors in P.L. 110-244 included the 25-year limit and omitted inclusion for IM in 23 U.S.C. 119.

v A State may do this when the more specific location of the future Interstate is consistent with statutory language. The determination of consistency with language in Section 1105(e)(5) of the ISTEA, as amended, is an administrative FHWA decision. However, this determination allows a reasonable interpretation that is, at the time, consistent with a public interest.

vi If the future Interstate number has been assigned in the statutory language, no coordination on route numbering is required. Otherwise, coordination is generally required if the route numbering substantially affects more than one State. If the corridor in question is completely within one State, no coordination on route numbering is required unless the highway is close to a border and coordination is administratively deemed to be necessary in the public interest. Also, even where formal coordination does not occur, notifications of various kinds are required, for example, notification to AASHTO and neighboring States.

vii In some cases the law itself constitutes part of a public announcement. If the State then places "future Interstate" on maps (hard copy and electronic) for a route within the corridor, that constitutes a further public announcement. In some cases, depending on the exact statutory language, the combination of the law and the maps may be sufficient public notice to allow placement of information signs, subject to Division office approval of wording and location.

viii Designations of two future KY corridors in P.L. 110-244 included the 25-year limit and omitted inclusion for IM in 23 U.S.C. 119. Note that MAP-21 eliminated the Interstate Maintenance (IM) program, so this will be a moot point once the period of availability for IM funds has expired.

ix Per 23 CFR Part 771, an environmental action would be required when federal funds are to be used in design and construction of the highway.

x See endnote iii.

Updated: 06/20/2013
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