State and Local Transportation Resources
Policy and Technical Guidance
- Main Transportation Conformity Page
- General Information
- Conformity Information for 2008 Ozone NAAQS Nonattainment Areas
- Policy and Technical Guidance
- Training Materials
- Adequacy Review of SIP Submissions
- Regional Contacts
This page contains policy guidance issued by EPA and/or the U.S. Department of Transportation to assist state and local transportation and air quality agencies implement the transportation conformity program. Policy guidance can be found on the following topics:
- Transportation Planning and Conformity Requirements
- Project-Level Conformity
- Emission Models and Conformity
- State Implementation Plans (SIPs) and Conformity
- Quantifying Benefits of Control Measures in SIPs and Conformity
- Land Use and Conformity
- March 2, 1999 Conformity Court Decision
Transportation Planning and Conformity Requirements
Baseline Year for the Baseline Year Test (in 40 CFR 93.119)
This page provides a table showing the baseline year to be used for each NAAQS and the regulatory provision where it is found.
Transportation Conformity Guidance for 2008 Ozone NAAQS Nonattainment Areas (PDF) (24pp, 180K, EPA-420-B-12-045, July 2012)
This document provides guidance for meeting transportation conformity requirements in areas designated nonattainment for the 2008 ozone national ambient air quality standards (“2008 ozone NAAQS”). Note: On December 23, 2014, the DC Circuit Court vacated EPA’s revocation of the 1997 ozone NAAQS for transportation conformity purposes only in NRDC v. EPA (12/23/2014). On March 6, 2015 EPA published a final rule revoking the 1997 ozone NAAQS for all purposes. (80 FR 12264) The final rule will be effective on April 6, 2015.
- Transportation Conformity Guidance for 2012 PM2.5 Nonattainment Areas (PDF) (19 pp, 206K, EPA-420-B-15-091, November 2015)
This document provides guidance for meeting transportation conformity requirements in areas designated nonattainment for the 2012 PM2.5 national ambient air quality standards.
Guidance for Transportation Conformity Implementation in Multi-Jurisdictional Nonattainment and Maintenance Areas (PDF) (54 pp, 589K, EPA-420-B-12-046, July 2012)
This guidance describes how transportation conformity determinations are done in areas where multiple metropolitan planning organizations (MPOs), states and/or other agencies have jurisdiction in a nonattainment or maintenance area. This guidance updates and supersedes the July 2004 “Companion Guidance for the July 1, 2004 Final Transportation Conformity Rule: Conformity Implementation in Multi-Jurisdictional Nonattainment and Maintenance Areas for Existing and New Air Quality Standards”. This guidance has been updated to apply to existing and future NAAQS, consistent with the Transportation Conformity Rule Restructuring Amendments.
Contact: Laura Berry at email@example.com
- Updated guidance on substituting and adding transportation control measures to approved state air quality plans(PDF) (35 pp, 401K, EPA420-B-09-002, January 2009 )
This document provides updated guidance to state and local air quality and transportation agencies on implementing the Clean Air Act provision that establishes a streamlined process for substituting or adding transportation control measures to an approved state air quality plan. Transportation control measures, such as public transit and carpooling, can provide alternatives to the public that reduce motor vehicle emissions. This document supersedes the section of the February 14, 2006 interim guidance on implementing the Clean Air Act amendments made by SAFETEA-LU that addressed this provision.
Contact: Rudy Kapichak at firstname.lastname@example.org
- EPA and DOT Joint Guidance for the Use of Latest Planning Assumptions in Transportation Conformity Determinations (23 pp, 343K, EPA420-B-08-901, December 2008)
This guidance document supersedes the January 18, 2001 guidance memorandum to address the July 1, 2004 transportation conformity final rule revisions on the use of latest planning assumptions in transportation conformity determinations.
Contact: Meg Patulski or email@example.com
- Please see www.epa.gov/otaq/stateresources/transconf/projectlevel-hotspot.htm for EPA’s policy and technical guidance related to project-level conformity, including:
Emission Models and Conformity
- The information here pertains to emissions models for regional conformity analyses. Information on emissions models for quantitative PM and CO hot-spot conformity analyses can be found at: https://www.epa.gov/otaq/stateresources/transconf/projectlevel-hotspot.htm#models-methods
- MOVES2014a model is now available
EPA’s Office of Transportation and Air Quality (OTAQ) has developed the MOtor Vehicle Emission Simulator (MOVES). See the MOVES website for further details on the model’s development and other technical supporting materials. MOVES2014a is the latest version of the MOVES emissions model and is now available. MOVES2014a is a minor update to MOVES2014, the previous major release of MOVES.
- Federal Register Notice of Availability: Official Release of MOVES2014 Motor Vehicle Emissions Model for Emissions Inventories in SIPs and Transportation Conformity (PDF) (5 pp, 230K, published October 7, 2014)
This notice approves the use of MOVES2014 and MOVES2014a in official SIP submissions and starts a two-year grace period before MOVES2014 and MOVES2014a are required to be used in new regional emissions analyses for transportation conformity determinations outside of California. For transportation conformity questions, contact: Astrid Terry at firstname.lastname@example.org. For SIP questions, contact Rudy Kapichak at email@example.com.
- Policy Guidance on the Use of
MOVES2014 for State Implementation Plan Development, Transportation Conformity, and Other Purposes (PDF) (18 pp, 230k, EPA-420-B-14-008)
This document describes how and when to use MOVES2014 and subsequent minor revisions, including MOVES2014a, for SIP development, transportation conformity, general conformity, and other purposes.
- MOVES2014 and MOVES2014a Technical Guidance: Using MOVES to Prepare Emission Inventories for State Implementation Plans and Transportation Conformity (PDF) (63 pp, 1.0MB, EPA-420-B-15-093, November 2015)
This document provides guidance on appropriate input assumptions and sources of data for the use of MOVES2014 and MOVES2014a in SIP submissions and regional emissions analyses for transportation conformity purposes.
Using MOVES to Prepare Emission Inventories in State Implementation Plans and Transportation Conformity: Technical Guidance for MOVES2010, 2010a and 2010b (63 pp, 482k, EPA-420-B-12-028, April 2012)
This document provides guidance on appropriate input assumptions and sources of data for the use of MOVES2010, MOVES2010a, and MOVES2010b in SIP submissions and regional emissions analyses for transportation conformity purposes.
Note: MOVES2010, MOVES2010a, and MOVES2010b can be used for conformity purposes until October 7, 2016, the end of the MOVES2014 grace period.
- Use of EMFAC model in California
- Federal Register Notice of Availability: Official Release of EMFAC2014 Motor Vehicle Emission Factor Model for Use in the State of California (December 14, 2015)
This notice describes EPA's approval of the EMFAC2014 model for SIP and transportation conformity purposes in California. It also announces a 24-month grace period, after which EMFAC2014 must be used for all new regional emissions analyses and CO, PM10 and PM2.5 hot-spot analyses in California (EMFAC2011 can continue to be used during the grace period). EPA's approval of the model does not affect MOVES model users in other states.
Contact: Karina O'Connor at firstname.lastname@example.org.
- Guidance on other models
- Federal Register Announcement of Availability: Official Release of January 2011 AP-42 Methods for Estimating Re-Entrained Road Dust from Paved Roads (PDF) (3 pp, 62K, February 2011)
This announcement describes EPA’s approval of the January 2011 AP-42 methods for use in SIPs and transportation conformity. A two-year grace period, which ends February 4, 2013, applies before the January 2011 AP-42 methods must be used for new regional emissions analyses for transportation conformity determinations. This document also supersedes the portions of the August 2007 guidance memo (next item, below) that cover estimating dust from paved roads.
- Policy Guidance on the Use of the November 1, 2006, Update to AP-42 for Re-entrained Road Dust for SIP Development and Transportation Conformity (EPA420-B-07-005, August 2007)
This guidance provides details about the changes made to the AP-42 methods for road dust and how and when to use them in PM2.5 state implementation plan development and transportation conformity determinations. This guidance supersedes the AP-42 portions of EPA's February 24, 2004, guidance, which addressed both MOBILE6.2 and AP-42 (next item, below). Note that the portions of this guidance referring to paved road dust are no longer in effect, as they have been replaced by EPA’s Federal Register announcement of February 4, 2011, found immediately above.
Transportation Conformity Guidance for Areas Reaching the End of the Maintenance Period (PDF) (8 pp, 212K, EPA-420-B-14-093, October 2014)
This guidance explains when transportation conformity requirements end for maintenance areas. This subject is relevant when areas approach the end of the 20 year maintenance period for certain national ambient air quality standards.
Contact: Laura Berry or email@example.com
- Guidance for Developing Transportation Conformity State Implementation Plans (PDF) (31 pp, 277K, EPA420-B-09-001, January 2009)
This document provides guidance on the statutory and regulatory requirements for states to develop conformity state implementation plans. This document supersedes the November 2004 Conformity SIP Guidance and Section 7 of the Interim Guidance for Implementing the Transportation Conformity Provisions in the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) (February 2006).
- Checklist for Developing a Conformity SIP (PDF) - Appendix A (6 pp, 115K)
- Editable Rule Model (DOC) - Appendix B (8 pp, 98K, free Word viewer )
- Court Decision on the Phase 1 Ozone Implementation Rule
On June 8, 2007, the U.S. Court of Appeals for the District of Columbia Circuit responded to our petition for rehearing on the Court's December 22, 2006, decision on the Phase 1 Rule to implement the 8-hour ozone national ambient air quality standard (NAAQS). To assist Regions, Federal, State, local agencies, and Tribes, a memo (PDF) (4 pp, 827K) was issued to the EPA regional offices on June 15, 2007. The memo summarizes the Court's opinion, and its implications for transportation conformity and the June 15, 2007, due date for submission of state implementation plans for nonattainment areas.
Contact: Meg Patulski at firstname.lastname@example.org or
Rudy Kapichak at email@example.com
- 2001 Limited Maintenance Plan for moderate PM10 (PDF) (11pp, 335K)
- 1995 Limited Maintenance Plan for nonclassifiable CO Nonattainment Areas(PDF) (7pp, 1.3M)
- Diesel Retrofits: Quantifying and Using Their Emission Benefits in SIPs and Conformity - Guidance for State and Local Air and Transportation Agencies (PDF) (70 pp, 1.0MB, EPA-420-B-14-007, February 2014 (supersedes EPA420-B-06-005, June 2006)
This document provides guidance on quantifying and using emission reductions from highway and nonroad diesel vehicles, engines, and equipment that have been retrofitted. The guidance discusses how emission reductions from diesel retrofit projects can be used in a SIP and in transportation conformity and general conformity determinations, based on the new MOVES2010b methodology described in this guidance.
- Commuter Programs: Quantifying and Using Their Emission Benefits in SIPs and Conformity – Guidance for State and Local Air and Transportation Agencies
This guidance describes how to credit commuter benefit programs in a SIP or transportation conformity determination.
Contact: Laura Berry at firstname.lastname@example.org
Guidance for Quantifying and Using Long Duration Switch Yard Locomotive Idling Emission Reductions in State Implementation Plans(PDF) (24 pp, 399K, EPA-420-B-09-037, October 2009)
This document provides guidance to state air pollution control agencies and the general public on how control measures to reduce switch yard locomotive idling emissions may be used to meet SIP requirements and conformity. Update of June 2013: The default locomotive emission factors included in this guidance have since been updated; consult www.epa.gov/otaq/locomotives.htm for the most recent emission factors. In addition, Appendix I to EPA's Transportation Conformity Guidance for Quantitative Hot-spot Analyses in PM2.5 and PM10 Nonattainment and Maintenance Areas describes how to estimate locomotive emissions at the project level and may be a useful resource when quantifying locomotive emission reductions.
- Comparing Methodologies to Assess Transportation and Air Quality Impacts of Brownfields and Infill Development (PDF) (49 pp, 17K, EPA-231-R-01-001, August 2001)
This document describes four methods for characterizing the air quality benefits resulting from infill development, compares these methodologies, and examines their advantages and disadvantages. It also includes the June 7, 2001 guidance memo listed directly below.
- Guidance on Applicable Methodologies to Account for the Benefits of Infill in SIPs and Conformity Determinations (PDF), June 7, 2001 (7 pp, 113K)
This memo guides the use of the four methods in preparing SIPs and transportation conformity determinations.
Contact: Laura Berry email@example.com
- Final Policy Guidance: Improving Air Quality Through Land Use Activities. January 2001
This document discusses how to include land use activities in a SIP. It includes examples of land use activities and discusses requirements. (See Chapter 8 for conformity requirements and examples.)
- Announcement (PDF) (1p, 10K)
- Complete Report: Improving Air Quality Through Land Use Activities (PDF) (110 pp, 1.1M, EPA420-R-01-001, January 2001)
- EPA's Conformity Guidance on Implementation of March 2, 1999, Conformity Court Decision (PDF) (11 pp, 46K, EPA420-F-99-025, May 1999)
This guidance includes details about using submitted budgets in conformity, EPA's new adequacy review process, non-federal projects, SIP disapprovals, and certain safety margins consistent with the court decision. EPA released this guidance on May 14, 1999.
- U.S. DOT's Revised Guidance for the Implementation of March 2, 1999, Conformity Court Decision
This guidance document was released on January 2, 2002, and supersedes and replaces all previous FHWA and FTA guidance implementing the Court's decision, including the supplemental guidance issued on June 18, 1999. It covers projects that can proceed during a conformity lapse.
- Revised Guidance for Implementing the March 1999 Circuit Court Decision Affecting Transportation Conformity (PDF) (4 pp, 48K)
U.S. DOT's February 7, 2002 Federal Register Notice announcing their revised guidance on projects that can proceed during a conformity lapse. This notice provides DOT's rational and justification for revising the guidance.
- May 20, 2003, FHWA/FTA Guidance: Clarification of Transportation Conformity Requirements for FHWA/FTA Projects Requiring Environmental Impact Statements (PDF) (2 pp, 107K)
- April 9, 2003, FTA Guidance: Revised FTA Procedures for a conformity lapse (PDF) (2 pp, 2.3M) addresses funding and approval of FTA projects during a conformity lapse.
- June 10, 1999, Federal Register Notice: Adequacy Status of Submitted State Implementation Plans for Transportation Conformity Purposes (Can be found at U.S. Government Printing Office)
Contact: Laura Voss Berry at firstname.lastname@example.org