Air Quality Planning and SIPs
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Transportation conformity ensures that Federal funding and approval goes to those transportation activities that are consistent with air quality goals and can have a significant impact on the transportation planning process. Transportation officials must be involved in the air quality planning process to ensure that emissions inventories, emissions budgets, and transportation control measures (TCMs) are appropriate and consistent with the transportation vision of a region.
Each State air quality agency is tasked with determining how best to achieve the Clean Air Act's (CAA's) goals and with developing state implementation plans (SIPs) for achieving health-based air quality standards. In some states, local air quality agencies also play a major role in air quality planning. SIPs are collections of regulations and measures used by a State to reduce emissions from stationary, area, and mobile sources and demonstrate attainment and maintenance of air quality standards. Decisions made in the air quality planning process and during SIP development can have a direct effect on transportation plans and projectcs. Transportation agencies need to participate fully in the air quality planning process to ensure that the decisions made reflect community priorities, including mobility.
Policy & Guidance
- MOVES2014 Technical Guidance: Using MOVES to Prepare Emission Inventories for State Implementation Plans and Transportation Conformity (PDF) (EPA, January 2015) - This document provides guidance on appropriate input assumptions and sources of data for the use of MOVES2014 in SIP submissions and regional emissions analyses for transportation conformity purposes.
- Transportation Conformity Guidance for Areas Reaching the End of the Maintenance Period (PDF) (EPA, 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.
- Policy Guidance on the Use of MOVES2014 and Subsequent Minor Revisions for State Implementation Plan Development, Transportation Conformity, and Other Purposes (PDF) (EPA, July 2014) - This document describes how and when to use the MOVES2014 for SIP development, transportation conformity, general conformity, and other purposes.
- MOVES2014 Questions and Answers (PDF) (EPA, July 2014) This document highlights the differences between MOVES2014 and earlier versions of MOVES and explains EPA policy on using MOVES2014 in State Implementation Plans and Transportation Conformity Analyses.
- MOVES2010b Questions and Answers (PDF) (April 2012) - This document highlights the differences between MOVES2010b and earlier versions of MOVES and explains EPA policy on using MOVES2010b in State Implementation Plans and Transportation Conformity Analyses.
- Policy Guidance on the Use of MOVES2010 and Subsequent Minor Revisions for State Implementation Plan Development, Transportation Conformity, and Other Purposes (PDF) (April 2012) - This document describes how and when to use the MOVES2010 (and subsequent minor revisions like MOVES2010b) for SIP development, transportation conformity, general conformity, and other purposes.
- Using MOVES to Prepare Emission Inventories in State Implementation Plans and Transportation Conformity: Technical Guidance for MOVES2010, 2010a and 2010b (PDF) (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.
- MOVES2010 Mobile Source Emissions Model: Questions and Answers (PDF) (December 2009) - This document describes the model and provides general information for model use.
- Federal Register Notice of Availability: Official Release of EMFAC2011 Motor Vehicle Emission Factor Model for Use in the State of California (March 2013) - In this notice, EPA is approving and announcing that EMFAC2011 is available to use in statewide California SIP development and for regional emissions analyses and CO, PM 10 and PM 2.5 hot-spot analyses for transportation conformity. EMFAC2011 must be used for all new regional emissions analyses and CO, PM 10 and PM 2.5 hot-spot analyses that are started on or after September 6, 2013.
- Federal Register Notice of Availability: Official Release of MOVES2010 Motor Vehicle Emissions Model for Emissions Inventories in SIPs and Transportation Conformity (March 2010) - This notice approves the use of MOVES2010 in official SIP submissions and starts a two-year grace period before MOVES2010 is required to be used in new regional emissions analyses for transportation conformity determinations outside of California.
- Guidance for Developing Transportation Conformity State Implementation Plans (January 2009) - EPA guidance on the statutory and regulatory requirements for states to develop conformity SIPs. 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).
- Policy Guidance on Use of November 2006 Update to AP-42 for Re-entrained Road Dust for SIP Development and Transportation Conformity (August 2007) - EPA guidance on changes made to the AP-42 methods for road dust and how and when to use them in PM2.5 SIPs and transportation conformity determinations. This guidance supersedes the AP-42 portions of EPA's February 2004 guidance, which addressed both MOBILE6.2 and AP-42. The portions of the February 2004 guidance addressing MOBILE6.2 remain in effect.
- Interim Guidance for Implementing the Transportation Conformity Provisions in SAFETEA-LU (February 2006) - Memorandum from FHWA, FTA, and EPA concerning guidance on implementing the transportation conformity-related provisions contained in SAFETEA-LU - this interim guidance pertained to the time period before the federal transportation conformity rule was revised
- Guidance for Determining the "Attainment Years" for Transportation Conformity in New 8-Hour Ozone and PM2.5 Nonattainment Areas (March 2005) - EPA guidance for 8-hour ozone and PM2.5 nonattainment areas in selecting attainment dates for use in transportation conformity determinations both before and after SIPs are submitted. It also describes some flexibilities that are available to areas using interim emission or budget tests in choosing which years to perform a regional emissions analysis.
- Policy Guidance on the Use of MOBILE6.2 and the December 2003 AP-42 Method for Re-Entrained Road Dust for SIP Development and Transportation Conformity (February 2004) - EPA guidance that describes how and when to use MOBILE 6.2 and the December 2003 AP-42 method in SIP development and transportation conformity determinations
- Information: Limited Maintenance Plans (September 2001) - Memorandum from EPA detailing instances when moderate PM10 nonattinment areas can be redesignated to attainment with a streamlined maintenance plan
- Memorandum of Understanding between DOT and EPA on Transportation Conformity (April 2000) - MOU between DOT and EPA to provide for timely review and comment on transportation and air quality planning documents and to establish a framework for resolving outstanding issues to facilitate timely conformity decisions.