Transportation Conformity: Chronological List of Rulemakings

EPA has published several rule amendments in the Federal Register since transportation conformity was enacted as part of the 1990 Clean Air Act. These previous rulemakings include preamble text that explain rule provisions that remain in place today and can be accessed here.

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Transportation Conformity Rule Restructuring Amendments

This final rule restructures several sections of the existing transportation conformity rule so that the rule applies to any new or revised NAAQS EPA establishes.

Final Rule (PDF) (57 pp, 288K, published March 14, 2012)
Final Rule: Fact Sheet (PDF) ( 2pp, 555K, EPA-420-F-12-009, February 2012)
Proposed Rule (PDF) 13 pp, 119K, published August 13, 2010)
Proposed Rule: Fact Sheet (PDF) (3 pp, 516K, EPA-420-F-10-001, August 2010)

Transportation Conformity Rule: MOVES Regional Grace Period Extension

This final rule extends the grace period before the MOtor Vehicle Emission Simulator model (currently MOVES2010a) is required for regional emissions analyses for transportation conformity determinations (“regional conformity analyses”). This final rule provides an additional year to the previously established two-year conformity grace period, which is now extended to March 2, 2013.

Final Rule (PDF) (8 pp, 180K, published February 27, 2012)
Fact Sheet (PDF) (2 pp, 521K, EPA-420-F-12-002, February 2012)
Proposed Rule (PDF) (7 pp, published October 13, 2011)
Direct Final Rule (PDF) (8 pp, 181K, published October 13, 2011)
Direct Final Rule Withdrawal (PDF) (1 pp, 138K, published December 5, 2011)

PM Amendments

Transportation Conformity Rule PM2.5 and PM10 Amendments (published March 24, 2010)
This PM amendments final rule amends the conformity regulation to reflect the October 17, 2006 final rule that strengthened the 24-hour PM2.5 national ambient air quality standard (NAAQS) and revoked the annual PM10 NAAQS. The final PM amendments rule also addresses a court remand concerning hot-spot analyses; this portion of the rule applies to PM2.5 and PM10 and carbon monoxide nonattainment and maintenance areas.

Final rule (PDF) (27 pp, 313 K, published March 24, 2010)
Fact Sheet: Final Rule (PDF) (2 pp, 129K, EPA-420-F-10-011, March 2010)
Proposed Rule (PDF) (20 pp, 224K, published May 15, 2009)
Fact Sheet: Proposed Rule (PDF) (3 pp, 188K, EPA-420-F-09-005, May 2009)

SAFETEA-LU Rulemaking

Transportation Conformity Rule Amendments to Implement Provisions Contained in the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (published January 24, 2008)
EPA has updated the transportation conformity rule to make it consistent with the Clean Air Act as amended by SAFETEA-LU.

Final Rule (PDF) (23 pp, 200K, published January 24, 2008)
Fact Sheet (PDF) (2 pp, 101K, EPA-420-F-08-002, January 2008)
Proposed Rule (PDF) (23 pp, 430K, published May 2, 2007)
Proposed Rule Fact Sheet (PDF) (3 pp, 93K, EPA-420-F-07-018, April 2007)

Rulemakings that Address 8-hour Ozone and Particulate Matter Air Quality Standards

March 10, 2006 Transportation Conformity Rule That Addresses Requirements for Project-level Conformity Determinations in PM2.5 and PM10 Nonattainment and Maintenance Areas (including supporting documentation).
EPA published a final rule that establishes requirements for project-level conformity determinations in PM2.5nonattainment and maintenance areas, and that revises the existing requirements for project-level determinations in PM10 areas.
May 6, 2005 Transportation Conformity Rule That Addresses PM2.5 Precursors (including supporting documentation).
EPA published a final rule that addresses the requirements for considering transportation-related PM2.5precursor emissions in conformity.
July 1, 2004 Final Rule (including supporting documentation).
This major rule amends specific provisions of the transportation conformity rule to address the new ozone and PM2.5 air quality standards and the March 2, 1999, conformity court decision. This rulemaking also includes preamble text that explains these changes to the conformity rule.

August 6, 2002, Final Rule

Final Rule: Transportation Conformity Rule Amendments: Minor Revision of 18-Month Requirement for Initial SIP Submissions and Addition of Grace Period for Newly Designated Nonattainment Areas (PDF) (75K, August 6, 2002) This final rule changes two provisions of the conformity rule. The first change will implement a 2000 Clean Air Act amendment that provides a one-year conformity grace period for areas that are designated nonattainment for the first time. The second change revises the timing for determining conformity following the initial submission of a state air quality plan.
Proposed Rule: Transportation Conformity Rule Amendments: Minor Revision of 18-Month Requirement for Initial SIP Submissions and Addition of Grace Period for Newly Designated Nonattainment Areas (PDF) (68K, October 5, 2001)

July 28, 2000, Federal Register Supplemental Notice of Proposed Rule

Motor Vehicle Emissions Budgets in Attainment Demonstrations for the One-Hour National Ambient Air Quality Standard for Ozone (PDF) (6 pp, 260K, published July 28, 2000). This notice supplements a December 16, 1999 proposal to act on attainment demonstrations for ten areas in the eastern United States. It also clarifies when motor vehicle emissions budgets apply for the purposes of transportation conformity and it reopens the comment period to address issues relating to the applicability of budgets and accept additional information on proposed December 16, 1999 action.

April 10, 2000, Final Rule

Final Rule: Transportation Conformity Amendment: Deletion of the Grace Period (PDF) (8 pp, 239K, published April 10, 2000). This rule deletes the grace period for transportation conformity in newly-designated nonattainment areas. This final rule is consistent with a 1997 court decision and addresses issues raised in a Petition for Reconsideration of the original 1993 transportation conformity rule.
Proposed Rule: Transportation Conformity Amendment: Deletion of the Grace Period (PDF) (6 pp, 227K, published November 30, 1999)