CAA 176(c) – Reference Document for Informational Purposes Only 

Clean Air Act Section 176(c) 

NOTE: This document includes Clean Air Act section 176(c) as amended by 

SAFETEA-LU. EPA is providing this document for informational purposes only. 

From the U.S. Code Online via GPO Access 

[wais.access.gpo.gov] 

[Laws in effect as of January 7, 2003] 

[Document not affected by Public Laws enacted between 

January 7, 2003 and February 12, 2003] 

[CITE: 42USC7506] 

TITLE 42--THE PUBLIC HEALTH AND WELFARE 

CHAPTER 85--AIR POLLUTION PREVENTION AND CONTROL 

SUBCHAPTER I--PROGRAMS AND ACTIVITIES 

Part D--Plan Requirements for Nonattainment Areas 

subpart 1--nonattainment areas in general 

Sec. 7506. Limitations on certain Federal assistance 

(a), (b) Repealed. Pub. L. 101-549, title I, Sec. 110(4), Nov. 15, 1990, 

104 Stat. 2470 

(c) Activities not conforming to approved or promulgated plans 

(1) No department, agency, or instrumentality of the Federal Government shall engage 

in, support in any way or provide financial assistance for, license or permit, or approve, 

any activity which does not conform to an implementation plan after it has been approved 

or promulgated under section 7410 of this title. No metropolitan planning organization 

designated under section 134 of title 23, shall give its approval to any project, program, 

or plan which does not conform to an implementation plan approved or promulgated 

under section 7410 of this title. The assurance of conformity to such an implementation 

plan shall be an affirmative responsibility of the head of such department, agency, or 

instrumentality. Conformity to an implementation plan means-- 

(A) conformity to an implementation plan's purpose of eliminating or reducing the 

severity and number of violations of the national ambient air quality standards and 

achieving expeditious attainment of such standards; and 

(B) that such activities will not--

(i) cause or contribute to any new violation of any standard in any area; 

(ii) increase the frequency or severity of any existing violation of any standard in 

any area; or 

(iii) delay timely attainment of any standard or any required interim emission 

reductions or other milestones in any area. 

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The determination of conformity shall be based on the most recent estimates of 

emissions, and such estimates shall be determined from the most recent population, 

employment, travel and congestion estimates as determined by the metropolitan planning 

organization or other agency authorized to make such estimates. 

(2) Any transportation plan or program developed pursuant to title 23 or chapter 53 of 

title 49 shall implement the transportation provisions of any applicable implementation 

plan approved under this chapter applicable to all or part of the area covered by such 

transportation plan or program. No Federal agency may approve, accept or fund any 

transportation plan, program or project unless such plan, program or project has been 

found to conform to any applicable implementation plan in effect under this chapter. In 

particular--

(A) no transportation plan or transportation improvement program may be adopted 

by a metropolitan planning organization designated under title 23 or chapter 53 of title 

49, or be found to be in conformity by a metropolitan planning organization until a final 

determination has been made that emissions expected from implementation of such plans 

and programs are consistent with estimates of emissions from motor vehicles and 

necessary emissions reductions contained in the applicable implementation plan, and that 

the plan or program will conform to the requirements of paragraph (1)(B); 

(B) no metropolitan planning organization or other recipient of funds under title 23 

or chapter 53 of title 49 shall adopt or approve a transportation improvement program of 

projects until it determines that such program provides for timely implementation of 

transportation control measures consistent with schedules included in the applicable 

implementation plan; 

(C) a transportation project may be adopted or approved by a metropolitan planning 

organization or any recipient of funds designated under title 23 or chapter 53 of title 49, 

or found in conformity by a metropolitan planning organization or approved, accepted, or 

funded by the Department of Transportation only if it meets either the requirements of 

subparagraph (D) or the following requirements-- 

(i) such a project comes from a conforming plan and program; 

(ii) the design concept and scope of such project have not changed significantly 

since the conformity finding regarding the plan and program from which the project 

derived; and 

(iii) the design concept and scope of such project at the time of the conformity 

determination for the program was adequate to determine emissions. 

(D) Any project not referred to in subparagraph (C) shall be treated as conforming to 

the applicable implementation plan only if it is demonstrated that the projected emissions 

from such project, when considered together with emissions projected for the conforming 

transportation plans and programs within the nonattainment area, do not cause such plans 

and programs to exceed the emission reduction projections and schedules assigned to 

such plans and programs in the applicable implementation plan. 

(E) The appropriate metropolitan planning organization shall redetermine 

conformity of existing transportation plans and programs not later than 2 years after the 

date on which the Administrator— 

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CAA 176(c) – Reference Document for Informational Purposes Only 

(i) finds a motor vehicle emissions budget to be adequate in accordance with 

section 93.118(e)(4) of title 40, Code of Federal Regulations (as in effect on October 1, 

2004); 

(ii) approves an implementation plan that establishes a motor vehicle emissions 

budget if that budget has not yet been determined to be adequate in accordance with 

clause (i); or 

(iii) promulgates an implementation plan that establishes or revises a motor 

vehicle emissions budget. 

(3) Until such time as the implementation plan revision referred to in paragraph (4)(C) 

is approved, conformity of such plans, programs, and projects will be demonstrated if--

(A) the transportation plans and programs-- 

(i) are consistent with the most recent estimates of mobile source emissions; 

(ii) provide for the expeditious implementation of transportation control measures 

in the applicable implementation plan; and 

(iii) with respect to ozone and carbon monoxide nonattainment areas, contribute 

to annual emissions reductions consistent with sections 7511a(b)(1) and 7512a(a)(7) of 

this title; and 

(B) the transportation projects--

(i) come from a conforming transportation plan and program as defined in 

subparagraph (A) or for 12 months after November 15, 1990, from a transportation 

program found to conform within 3 years prior to November 15, 1990; and 

(ii) in carbon monoxide nonattainment areas, eliminate or reduce the severity and 

number of violations of the carbon monoxide standards in the area substantially affected 

by the project. 

 With regard to subparagraph (B)(ii), such determination may be made as part of either 

the conformity determination for the transportation program or for the individual project 

taken as a whole during the environmental review phase of project development. 

(4) CRITERIA AND PROCEDURES FOR DETERMINING CONFORMITY 

(A) IN GENERAL—The Administrator shall promulgate, and periodically update, 

criteria and procedures for determining conformity (except in the case of transportation 

plans, programs, and projects) of, and for keeping the Administrator informed about, the 

activities referred to in paragraph (1). 

(B) TRANSPORTATION PLANS, PROGRAMS, AND PROJECTS–The Administrator, with 

the concurrence of the Secretary of Transportation, shall promulgate, and periodically 

update, criteria and procedures for demonstrating and assuring conformity in the case of 

transportation plans, programs, and projects. 

(C ) CIVIL ACTION TO COMPEL PROMULGATION—A civil action may be brought 

against the Administrator and the Secretary of Transportation under section 7604 of this 

title to compel promulgation of such criteria and procedures and the Federal district court 

shall have jurisdiction to order such promulgation. 

(D) The procedures and criteria shall, at a minimum-- 

(i) address the consultation procedures to be undertaken by metropolitan planning 

organizations and the Secretary of Transportation with State and local air quality agencies 

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and State departments of transportation before such organizations and the Secretary make 

conformity determinations; 

(ii) address the appropriate frequency for making conformity determinations, but 

; the frequency for making conformity determinations on updated transportation plans 

and programs shall be every 4 years, except in a case in which— 

(I) the metropolitan planning organization elects to update a transportation plan 

or program more frequently; or 

(II) the metropolitan planning organization is required to determine conformity 

in accordance with paragraph (2)(E); and 

(iii) address how conformity determinations will be made with respect to 

maintenance plans. 

(E). INCLUSION OF CRITERIA AND PROCEDURES IN SIP.—Not later than 

2 years after the date of enactment of the SAFETEA–LU the procedures under 

subparagraph (A) shall include a requirement that each State include in the State 

implementation plan criteria and procedures for consultation required by subparagraph 

(D)(i), and enforcement and enforceability (pursuant to sections 93.125(c) and 

93.122(a)(4)(ii) of title 40, Code of Federal Regulations) in accordance with the 

Administrator’s criteria and procedures for consultation, enforcement and 

enforceability.’’. 

(F) Compliance with the rules of the Administrator for determining the 

conformity of transportation plans, programs, and projects funded or approved under title 

23 or chapter 53 of title 49 to State or Federal implementation plans shall not be required 

for traffic signal synchronization projects prior to the funding, approval or 

implementation of such projects. The supporting regional emissions analysis for any 

conformity determination made with respect to a transportation plan, program, or project 

shall consider the effect on emissions of any such project funded, approved, or 

implemented prior to the conformity determination. 

(5) Applicability.--This subsection shall apply only with respect to— 

(A) a nonattainment area and each pollutant for which the area is designated as 

a nonattainment area; and 

(B) an area that was designated as a nonattainment area but that was later 

redesignated by the Administrator as an attainment area and that is required to develop a 

maintenance plan under section 7505a of this title with respect to the specific pollutant 

for which the area was designated nonattainment. 

(6) Notwithstanding paragraph 5,\1\ this subsection shall not apply with respect to an 

area designated nonattainment under section 7407(d)(1) of this title until 1 year after that 

area is first designated nonattainment for a specific national ambient air quality standard. 

This paragraph only applies with respect to the national ambient air quality standard for 

which an area is newly designated nonattainment and does not affect the area's 

requirements with respect to all other national ambient air quality standards for which the 

area is designated nonattainment or has been redesignated from nonattainment to 

attainment with a maintenance plan pursuant to section 7505a \2\ of this title (including 

any pre-existing national ambient air quality standard for a pollutant for which a new or 

revised standard has been issued). 

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(7) CONFORMITY HORIZON FOR TRANSPORTATION PLANS.— 

(A) IN GENERAL.—Each conformity determination required under this section 

for a transportation plan under section 134(i) of title 23, United States Code, or section 

5303(i) of title 49, United States Code, shall require a demonstration of conformity for 

the period ending on either the final year of the transportation plan, or at the election of 

the metropolitan planning organization, after consultation with the air pollution control 

agency and solicitation of public comments and consideration of such comments, the 

longest of the following periods: 

(i) The first 10-year period of any such transportation plan. 

(ii) The latest year in the implementation plan applicable to the area that contains 

a motor vehicle emission budget. 

(iii) The year after the completion date of a regionally significant project if the 

project is included in the transportation improvement program or the project requires 

approval before the subsequent conformity determination. 

(B) REGIONAL EMISSIONS ANALYSIS.—The conformity determination shall 

be accompanied by a regional emissions analysis for the last year of the transportation 

plan and for any year shown to exceed emission budgets by a prior analysis, if such year 

extends beyond the applicable period as determined under subparagraph (A). 

(C) EXCEPTION.—In any case in which an area has a revision to an 

implementation plan under section 175A(b) and the Administrator has found the motor 

vehicles emissions budgets from that revision to be adequate in accordance with section 

93.118(e)(4) of title 40, Code of Federal Regulations (as in effect on October 1, 2004), or 

has approved the revision, the demonstration of conformity at the election of the 

metropolitan planning organization, after consultation with the air pollution control 

agency and solicitation of public comments and consideration of such comments, shall be 

required to extend only through the last year of the implementation plan required under 

section 175A(b). 

(D) EFFECT OF ELECTION.—Any election by a metropolitan planning 

organization under this paragraph shall continue in effect until the metropolitan planning 

organization elects otherwise. 

(E) AIR POLLUTION CONTROL AGENCY DEFINED.—In this paragraph, the 

term ‘air pollution control agency’ means an air pollution control agency (as defined in 

section 302(b)) that is responsible for developing plans or controlling air pollution within 

the area covered by a transportation plan. 

(8) SUBSTITUTION OF TRANSPORTATION CONTROL MEASURES.— 

(A) IN GENERAL.—Transportation control measures that are specified in an 

implementation plan may be replaced or added to the implementation plan with alternate 

or additional transportation control measures 

(i) if the substitute measures achieve equivalent or greater emissions reductions 

than the control measure to be replaced, as demonstrated with an emissions impact 

analysis that is consistent with the current methodology used for evaluating the replaced 

control measure in the implementation plan; 

(ii) if the substitute control measures are implemented— 

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CAA 176(c) – Reference Document for Informational Purposes Only 

(I) in accordance with a schedule that is consistent with the schedule 

provided for control measures in the implementation plan; or 

(II) if the implementation plan date for implementation of the control 

measure to be replaced has passed, as soon as practicable after the implementation plan 

date but not later than the date on which emission reductions are necessary to achieve the 

purpose of the implementation plan; 

(iii) if the substitute and additional control measures are accompanied with 

evidence of adequate personnel and funding and authority under State or local law to 

implement, monitor, and enforce the control measures; 

(iv) if the substitute and additional control measures were developed through a 

collaborative process that included— 

(I) participation by representatives of all affected jurisdictions (including 

local air pollution control agencies, the State air pollution control agency, and State and 

local transportation agencies); 

(II) consultation with the Administrator; and 

(III) reasonable public notice and opportunity for comment; and 

(v) if the metropolitan planning organization, State air pollution control agency, 

and the Administrator concur with the equivalency of the substitute or additional control 

measures. 

(B) ADOPTION.— 

(i) Concurrence by the metropolitan planning organization, State air pollution 

control agency and the Administrator as required by subparagraph (A)(v) shall constitute 

adoption of the substitute or additional control measures so long as the requirements of 

subparagraphs (A)(i), (A)(ii), (A)(iii) and (A)(iv) are met. 

(ii) Once adopted, the substitute or additional control measures become, by 

operation of law, part of the State implementation plan and become federally enforceable. 

(iii) Within 90 days of its concurrence under subparagraph (A)(v), the State air 

pollution control agency shall submit the substitute or additional control measure to the 

Administrator for incorporation in the codification of the applicable implementation plan. 

Nothwithstanding any other provision of this Act, no additional State process shall be 

necessary to support such revision to the applicable plan. 

(C) NO REQUIREMENT FOR EXPRESS PERMISSION.—The substitution or 

addition of a transportation control measure in accordance with this paragraph and the 

funding or approval of such a control measure shall not be contingent on the existence of 

any provision in the applicable implementation plan that expressly permits such a 

substitution or addition. 

(D) NO REQUIREMENT FOR NEW CONFORMITY DETERMINATION.— The 

substitution or addition of a transportation control measure in accordance with this 

paragraph shall not require— 

(i) a new conformity determination for the transportation plan; or 

(ii) a revision of the implementation plan. 

(E) CONTINUATION OF CONTROL MEASURE BEING REPLACED.—A control 

measure that is being replaced by a substitute control measure under this paragraph shall 

remain in effect until the substitute control measure is adopted by the State pursuant to 

subparagraph (B). 

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CAA 176(c) – Reference Document for Informational Purposes Only 

(F) EFFECT OF ADOPTION.—Adoption of a substitute control measure shall 

constitute rescission of the previously applicable control measure. 

(9) LAPSE OF CONFORMITY.—If a conformity determination required under this 

subsection for a transportation plan under section 134(i) of title 23, United States Code, 

or section 5303(i) of title 49, United States Code, or a transportation improvement 

program under section 134(j) of such title 23 or under section 5303(j) of such title 49 is 

not made by the applicable deadline and such failure is not corrected by additional 

measures to either reduce motor vehicle emissions sufficient to demonstrate 

compliance with the requirements of this subsection within 12 months after such deadline 

or other measures sufficient to correct such failures, the transportation plan shall lapse.

 (10) LAPSE.—In this subsection, the term ‘lapse’ means that the conformity 

determination for a transportation plan or transportation improvement program has 

expired, and thus there is no currently conforming transportation plan or transportation 

improvement program.’’. 

\1\ So in original. Probably should be ``paragraph (5),''. 

\2\ See References in Text note below. 

(July 14, 1955, ch. 360, title I, Sec. 176, as added Pub. L. 95-95, title I, Sec. 129(b), Aug. 

7, 1977, 91 Stat. 749; amended Pub. L. 95-190, Sec. 14(a)(59), Nov. 16, 1977, 91 Stat. 

1403; Pub. L. 101-549, title I, Secs. 101(f), 110(4), Nov. 15, 1990, 104 Stat. 2409, 2470; 

Pub. L. 104-59, title III, Sec. 305(b), Nov. 28, 1995, 109 Stat. 580; Pub. L.104-260, Sec. 

1, Oct. 9, 1996, 110 Stat. 3175; Pub. L. 106-377, Sec. 1(a)(1) [title III], Oct. 27, 2000, 

114 Stat. 1441, 1441A-44.) 

References in Text 

 Section 7505a of this title, referred to in subsec. (c)(6), was in the original ``section 

175(A)'' and was translated as reading ``section 175A'', meaning section 175A of act July 

14, 1955, which is classified to section 7505a of this title, to reflect the probable intent of 

Congress. 

Codification 

 In subsecs. (c)(2) and (d), ``chapter 53 of title 49'' substituted for ``the Urban Mass 

Transportation Act [49 App. U.S.C. 1601 et seq.]'' and in subsec. (c)(4)(D) substituted for 

``Federal Transit Act'' on authority of Pub. L. 103-272, Sec. 6(b), July 5, 1994, 108 Stat. 

(the first section of which enacted subtitles II, III, and V to X of Title 49, Transportation), 

and of Pub. L. 102-240, title III, Sec. 3003(b), Dec. 18, 1991, 105 Stat. 2088, which 

provided that 

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references in laws to the Urban Mass Transportation Act of 1964 be deemed to be 

references to the Federal Transit Act. 

 Amendments 

2000--Subsec. (c)(6). Pub. L. 106-377 added par. (6). 

1996--Subsec. (c)(4)(D). Pub. L. 104-260 added subpar. (D). 

1995--Subsec. (c)(5). Pub. L. 104-59 added par. (5). 

 1990--Subsecs. (a), (b). Pub. L. 101-549, Sec. 110(4), struck out subsec. (a) which 

related to approval of projects or award of grants, and subsec. (b) which related to 

implementation of approved or promulgated plans. 

 Subsec. (c). Pub. L. 101-549, Sec. 101(f), designated existing provisions as par. (1), 

struck out ``(1)'', ``(2)'', ``(3)'', and ``(4)'' before ``engage in'', ``support in'', ``license or'', 

and ``approve, any'', respectively, substituted ``conform to an implementation plan after 

it'' for ``conform to a plan after it'', ``conform to an implementation plan approved'' for 

``conform to a plan approved'', and ``conformity to such an implementation plan shall'' 

for ``conformity to such a plan shall'', inserted ``Conformity to an implementation plan 

means--'' followed immediately by subpars. (A) and 

(B) and closing provisions relating to determination of conformity being based on recent 

estimates of emissions and the determination of such estimates, and added pars. (2) to (4). 

 1977--Subsec. (a)(1). Pub. L. 95-190 inserted ``national'' before ``primary''. 

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