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Home / MAP-21 / Fact Sheets / Federal Share

This MAP-21 fact sheet has been superseded by a FAST Act fact sheet.


Federal Share

Main statutory citation(s): MAP-21 §1508; 23 USC 120


The maximum share of project costs that may be funded with Federal-aid highway funds (the “Federal share”) varies based upon the Federal-aid program from which the project receives funding. In some cases the Federal share is also adjusted based on related statutory provisions.

“Standard” Federal share

23 USC 120 provides that except as otherwise provided, the Federal share payable shall be:

There are a number of exceptions and adjustments to the “standard” Federal share. See below (and program-specific fact sheets) for information about, and the applicability of, these exceptions and adjustments.

Adjustments to Federal share

Sliding scale

23 USC 120(a) and (b) authorize an upward adjustment (the “sliding scale”) to the Federal share for a State containing Federal and nontaxable Indian lands. A sliding scale State is eligible for an increased Federal share based upon the location of the project—90-95% for an Interstate project and 80-95% for any other project—without regard to the otherwise applicable Federal share of the programmatic funding source. The amount of the upward adjustment is based on the percentage of Federal and nontaxable Indian lands in the State. (See FHWA guidance for the specific share allowable in each sliding scale State under this provision).

Other adjustments to Federal share

Increased non-Federal share

23 USC 120(h) authorizes a State to contribute an amount in excess of the non-Federal share of any project under 23 USC, thus decreasing the Federal share for the project.

Transfers of funding between FHWA and FTA

Federal-aid highway funds made available for a transit project or transportation planning may be transferred to the Federal Transit Administration (FTA) and administered in accordance with FTA’s requirements (under chapter 53 of title 49). Similarly, Federal transit funding made available for a highway project or transportation planning may be transferred to FHWA and administered in accordance with title 23 requirements. In either case, the transferred funds remain subject to the Federal share that applied to the category from which the funding was derived. For more information, see FHWA Order 4551.1. [MAP-21 §1105; 23 USC 104(f)]

Federal Share for Selected Programs

Program Federal
(%) [1]
Plus eligible for…
scale [2]
100% for
types of
projects [3]
Up to 100%
for innovative
delivery methods [4]
100% for
development [5]
100% for
projects [6]
100% within
Indian reservations,
national parks,
and monuments[7]
National Highway Performance Program 80 / 90 [8], [9]
Surface Transportation Program 80 / 90 [8]
Highway Safety Improvement Program 90 [8], [10]    
Railway-Highway Crossings 90 [11]            
Congestion Mitigation & Air Quality Improvement Program 80 / 90 [8]    
Metropolitan Transportation Planning 80 [8]        
State Planning and Research 80 [12]            
Transportation Alternatives Program 80 / 90 [8]      
Recreational Trails Program 80 [13]          
Tribal Transportation Program 100 [14]            
Federal Lands Transportation Program 100 [13]            
Federal Lands Access Program 80 / 90 [8], [15]        
Puerto Rico Highway Program 80 / 90 [8]        
Territorial Highway Program (or any project in the specified territories) 100 [16]            
Emergency Relief 80-100 [17]          
Projects of National & Regional Significance 80 [18]            
Construction of Ferry Boats & Ferry Terminal Facilities 80 [19]            
Tribal High Priority Projects Program 100 [20]            
Highway Research & Development Program 80 [21]            
Technology & Innovation Deployment Program 80 [21]            
Training & Education 80 [21], [22]            
Intelligent Transportation Systems Program 80 [21]            

[1] The Federal share specified in this column may be subject (as specified) to one or more of the provisions referenced in the subsequent columns. In some circumstances the Federal share may also be modified by the provisions described above related to freight projects and projects requiring Federal toll authority.

[2] 23 USC 120(a)-(b).

[3] 23 USC 120(c)(1), as amended by MAP-21 §1508(1).

[4] 23 USC 120(c)(3), as amended by MAP-21 §1304.

[5] 23 USC 504(e), as amended by MAP-21 §52004(4)(A)(i).

[6] MAP-21 §1528(c).

[7] 23 USC 120(f).

[8] The “standard Federal share” of 90% for a project on the Interstate System (including a project to add high occupancy vehicle lanes or auxiliary lanes but excluding a project to add other lanes) and 80% for any other project or activity. [23 USC 120(a)-(b)]

[9] Beginning in FY 2016, the NHPP Federal share for a State that has not developed and implemented an asset management plan will be reduced to 65% until it develops and implements its plan. [MAP-21 §1106; 23 USC 119(e)(5)]

[10] 23 USC 148(j), as amended by MAP-21 §1112.

[11] 23 USC 130(f)(3).

[12] The Secretary may increase this share (up to 100%) if s/he determines that this would best serve the interests of the Federal-aid highway program. [MAP-21 §52005(2); 23 USC 505(d)]

[13] 23 USC 206(f) (which cites to 23 USC 120(b), with some specified exceptions).

[14] 23 USC 201(b)(7)(A), as amended by MAP-21 §1119.

[15] 23 USC 201(b)(7)(B), as amended by MAP-21 §1119.

[16] 23 USC 120(g) (as redesignated by MAP-21 §1508(3)).

[17] Emergency Relief (ER) funds are typically subject to the standard Federal share: 80%, with 90% on Interstates, in both cases subject to the sliding scale. However, this share may be adjusted as follows:

[18] SAFETEA-LU §1301(i).

[19] 23 USC 147(b).

[20] MAP-21 §1123(h)(2)(B).

[21] Except as expressly provided by MAP-21 or otherwise determined by the Secretary, projects and activities funded under Division E (Research and Education) of MAP-21 are subject to a Federal share of 80%. [MAP-21 §51001(b)]

[22] This share is reduced to 50% for activities carried out by a local technical assistance center and increased to 100% for activities carried out by a tribal technical assistance center. [MAP-21 §52004(2); 23 USC 504(b)(3)]

Page last modified on September 12, 2013
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