Office of Transportation and Air Quality

EPA-420-F-11-001

 October 2011

EPA Finalizes Transportation 

Conformity Rule: MOVES Regional 

Grace Period Extension

EPA is taking direct final action to extend the grace period before 

the MOtor Vehicle Emission Simulator model (MOVES2010a) is 

required for regional emissions analyses for transportation conformity 

determinations (“regional conformity analyses”). MOVES is EPA’s 

state-of-the-art model for estimating emissions from highway vehicles, 

based on analyses of millions of emission test results and considerable 

advances in the Agency’s understanding of vehicle emissions. 

This final rule ensures that air quality is protected and clarifies 

requirements for implementers under the extended grace period for 

regional conformity analyses. 

EPA has worked closely with the U.S. Department of Transportation 

to develop this final rule.

Background

Transportation conformity is a Clean Air Act requirement that ensures that federally supported highway and transit projects are consistent with state air quality 

implementation plans (SIPs). Conformity helps protect public health through early 

consideration of the air quality impacts of transportation decisions in places where 

air quality does not currently meet federal national ambient air quality standards 

(NAAQS) or has not met them in the past.

Key Elements of the Final Rule

•	 This final rule provides an additional year to the previously established twoyear conformity grace period. As a result, MOVES2010a is not required for 

Regulatory Announcement

new regional conformity analyses until March 2, 2013. 
Regulatory Announcement

2

•	 The final rule is based on unique circumstances presented by the transition to MOVES 

from the previous emissions model. Several state and local transportation and air quality 

agencies have requested additional transition time for using MOVES2010a in regional 

conformity analyses.

•	 This action does not affect EPA’s previous approval of the use of MOVES in official SIP 

submissions or the existing grace period before MOVES2010a is required for carbon 

monoxide and particulate matter hot-spot analyses for project-level conformity determinations (75 FR 79370). 

Health and Environmental Benefits

The final rule ensures that transportation activities are consistent with air quality goals of the 

transportation conformity program. The final rule ensures that all nonattainment and maintenance areas use conformity tests that ensure air quality progress continues in areas that need to 

attain or maintain the NAAQS. 

For More Information

You can access documents on transportation conformity on EPA’s Office of Transportation and 

Air Quality Web site at:

www.epa.gov/otaq/stateresources/transconf/index.htm

For further information on this final rule, please contact: 

Meg Patulski

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

2000 Traverwood Drive

Ann Arbor, MI 48105

734-214-4842

E-mail: patulski.meg@epa.gov

Or:

Astrid Larsen

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

2000 Traverwood Drive

Ann Arbor, MI 48105

734-214-4812

E-mail: larsen.astrid@epa.gov