This is a preliminary document prepared by a subgroup of members of the National and Regional Strategies Work Group as part of the Federal Advisory Committee Act (FACA) Subcommittee process. It is not an EPA document. This document has not been reviewed by the NRS Work Group and is subject to further work group discussion. Interested people should forward their comments to a member of the National and Regional Strategies Work Group or the Transportation Conformity Subgroup.

Transportation Conformity

Date: June 3, 1997

Contact: Betsy Bartlett, NYSDEC, (518) 457-2823, fax (518) 457-0794 and Bob Wyman, Latham & Watkins, (213) 485-1234, fax (213) 891-8763

Status: Draft #3. This draft incorporates comments submitted by the Federal Highway Administration on May 6, 1997 and reflects the discussions on May 15 and June 3 of the Transportation Conformity Subgroup and May 22 of the National and Regional Strategies Work Group.

Introduction

This paper discusses how and where transportation conformity should apply in areas that potentially violate or potentially contribute to a violation of the new/revised standards for ozone and particulate matter. The scope of the paper is limited to the issues that are unique to the application of transportation conformity to the presumably larger areas, and in some cases more rural areas, which are likely to be subject to additional emissions control requirements to attain the new/revised NAAQS for ozone and particulate matter.

Two issues are recognized but are beyond the scope of the issue paper. The first is a legal issue: Is there a legal constraint that would restrict transportation conformity to areas of violation, precluding application to AOIs or some portions of AOIs? This legal issue will be addressed in a different form. The second issue is a conformity issue, but it is not unique to application of conformity after promulgation of new/revised NAAQS: How can the time horizons for air quality planning and transportation planning be made to coincide? The difference in planning horizons—10-years for SIPs and 20-years for transportation plans—is noted but options for reconciling the difference are not developed.

Another group which is operating independently of the Implementation FACA Subcommittee, the Mobile Sources Technical Review Sub-Committee, is addressing several issues that arise in any application of transportation conformity or mobile source control strategy development. To avoid duplication and keep abreast of relevant work, these efforts are being coordinated with the other Subcommittee.

Transportation conformity is not the only arena in which multistate interactions could be significant during preparation of regional implementation plans and subsequent state implementation plans after promulgation of the new/revised NAAQS. Preparation of regional plans and planning institutions are addressed in these other issue papers: "Regional Air Management Partnerships and Areas of Influence" and "Institutional Mechanism for Development and Implementation of Regional Strategies."

The discussion of transportation conformity in this issue paper also overlaps somewhat with the Implementation FACA Subcommittee's discussion of "progress," rewards for early planning and implementation, and preparation of emissions inventories. Progress, in particular the requirements that apply prior to SIP approval, is discussed in the "Progress During SIP Development" issue paper. The "Rewards and Sanctions" issue paper briefly mentions transportation conformity in the discussion of how planning bodies can be encouraged to plan and implement plans early. The issue paper on air quality modeling and emissions inventories, "The Modeling Process and Emissions Inventories: Their Availability, Evaluation, Use, and Limitations" is also germane.

Background

What is transportation conformity?

Clean Air Act section 176(c) requires that the overall air quality impact of road construction and other transportation-related activities must be determined before such activities may take place. Specifically, the U.S. Department of Transportation (DOT) may not fund, approve, or support highway and transit activities unless it is demonstrated that they will not cause new violations, worsen existing violations, or delay timely attainment.

Transportation conformity regulations

EPA promulgated the transportation conformity rule on November 24, 1993, and it has been amended twice since. EPA is expecting a comprehensive set of amendments to be finalized this summer. The transportation conformity rule establishes the process by which DOT and metropolitan planning organizations (MPOs) determine the conformity of transportation plans, programs, and projects. Individual states are required to adopt conformity SIPs, which are for the most part verbatim copies of the federal rule. Although some states have adopted conformity SIPs, many states are waiting for EPA's amendments to be final before promulgating their own regulations.

Transportation vs. general conformity

EPA also published in November 1993 the "general conformity" rule, which governs federal actions other than highway and transit, such as airports and military bases. The transportation conformity issue paper does not discuss general conformity issues because there are substantial differences in both the issues and the audience. For example, only federal agencies are responsible for complying with general conformity. In contrast, transportation conformity is the responsibility of DOT, the states, and MPOs. Whereas state and local transportation agencies are intimately involved in the transportation conformity process, they are not always involved in the general conformity process. The interested parties for general conformity determinations depend on the project in question and may vary widely, due to the wide variety of actions subject to general conformity. In addition, because projects are not typically part of a comprehensive planning process in the way that highway and transit projects are, the general conformity rule's requirements are significantly different from those in the transportation conformity rule.

Some projects subject to general conformity involve highway or transit access that requires Federal Highway Administration/ Federal Transit Administration (FHWA/FTA) funding or approval (e.g., airport access roads). Those highway/transit projects that require FHWA/FTA funding or approval, or are sponsored by an agency that routinely receives FHWA/FTA funding, are subject to the transportation conformity rule. In addition, part of the general conformity requirements can be satisfied if the project is included in a transportation plan or program that has been found to conform under the transportation conformity rule.

How does transportation conformity work?

According to the Clean Air Act, transportation conformity applies in nonattainment and maintenance areas. Emissions from highway and transit activities must be consistent with the SIP's emissions estimates. The SIP establishes a "motor vehicle emissions budget," which represents the maximum motor vehicle emissions that would still enable an area to show reasonable further progress, attainment, or maintenance. Transportation investments may not be made unless the resulting emissions will be within the budget. If motor vehicle emissions are predicted to exceed the budget, either the SIP or the transportation plan must be modified before transportation projects can proceed.

Purposes of transportation conformity

In addition to this "budget test," the Clean Air Act outlines other elements of the conformity process. Taken together, the purposes of conformity can be summarized to include the following: (1) reinforce SIP goals and ensure that SIP motor vehicle emission targets for attainment and maintenance are met; (2) ensure that transportation plans, programs, and projects contribute to emission reduction strategies included in SIPs; (3) ensure timely implementation of transportation control measures in approved SIPs; (4) provide a process by which transportation and air quality planning agencies consider long-term impacts from transportation plans, programs, and projects; and (5) provide a forum for interagency and public debate regarding the air quality impacts of proposed transportation investments and how air quality and mobility goals should be reconciled.

An important aspect of conformity is the use of common planning tools, models, and databases by both transportation and air quality planners. Currently, nonattainment and maintenance area boundaries are approximately the same as the metropolitan planning area boundary. Thus, the SIP budget and the transportation planning process address roughly the same area with the same working assumptions.

Experiences with conformity to date

According to a February 1997 report by the National Governors' Association that was based on interviews with fourteen states, state experiences with the conformity process have been mixed. Conformity has enhanced the working relationships and communication among state and local air and transportation planners. In addition, some states have found conformity to be effective because it has been a catalyst for changing the transportation planning culture; it is a long-term process for ensuring transportation plans are consistent with air quality plans; and it has complemented state growth management and land-use policies. However, states believe the conformity process is too complex. Some states view conformity as an administrative exercise, believing that modifications to transportation systems have a minimal impact on air emissions and that the conformity process places too much emphasis on modeling and quantitative results.

After the conformity regulations were finalized in November 1993, EPA and DOT began working with states and other conformity stakeholders to address their concerns. This has resulted in several amendments to the conformity regulations, and the comprehensive amendments to streamline and add flexibility to the conformity process are expected to be finalized soon. EPA and DOT are working with Harvard University to conduct an objective assessment of the conformity process after the rule has been amended. A final report will be available in approximately 2000 (before conformity would be applying to areas impacted by the new/revised standards).

In addition, EPA and DOT have proposed a conformity pilot program that would allow areas to test innovative methods that streamline the conformity process. Under the pilot program, up to six areas would have additional flexibility to develop alternative conformity procedures. EPA and DOT are currently accepting applications for the pilot program, and the rule providing for the pilot program will be finalized this year.

What does the Interim Implementation Policy say about conformity?

The proposed Interim Implementation Policy states that transportation conformity determinations would not have to consider the new NAAQS until SIPs addressing the NAAQS are approved by EPA. Because existing SIPs will remain in place, conformity in existing nonattainment and maintenance areas would continue to be demonstrated using existing SIP budgets.

Issue 1. Where should transportation conformity apply?

Areas of violation (AOVs); areas of influence (AOIs); both AOVs and AOIs; or in existing nonattainment and maintenance areas only? Where should transportation conformity apply given the purposes of conformity and the planning requirements for AOIs and AOVs?

The full determination of applicability is complex, requiring resolution of several constituent issues. The first and most basic part involves the sufficiency of just air quality considerations in determining where transportation conformity applies. The second part involves specifically where transportation conformity applies if it does not apply throughout an AOI. The third part involves whether transportation conformity applies to preliminary or final AOIs. The last part involves whether and to what extent the transportation conformity process could vary by location.

A full resolution of the issue of where transportation conformity should apply requires judgments as to whether transportation conformity should apply everywhere in an AOI or only in portions of an AOI, selecting the portions according to criteria which have been developed by one or more federal and state agencies. One option is to apply transportation conformity everywhere in an AOI in recognition of the AOI as the geographical area containing anthropogenic and natural sources which contribute to at least one AOV.

The two most general options are: 1) transportation conformity should apply in any place within an AOI where mobile source emissions potentially affect attainment or maintenance of one or more NAAQS in an AOV or some other area, and 2) transportation conformity should apply in any place where transportation decisions will have an impact on air quality and a meaningful choice can be made between transportation alternatives. In both options, transportation conformity should apply to an AOV only if the AOV is in an AOI, and the AOV contains mobile sources.

The first option reflects the perspective that attaches primary importance to air quality linkages. The second option reflects the perspective that attaches coequal importance to air quality linkages and the potential leverage of the transportation conformity process over transportation planning.

If transportation conformity is to apply only to portions of an AOI, criteria are necessary to help guide decisions about the boundaries of the specific places where it applies. For example, transportation conformity could apply only to certain metropolitan areas, certain counties, or to areas whose SIPs contain local controls to reduce motor vehicle emissions. It could apply when a place's attainment or maintenance depends upon motor vehicle emissions being kept within a certain level (no matter what that level is). Conformity could apply if growth in a place's motor vehicle emissions would threaten an area's attainment or maintenance. The conformity process could be limited to areas where motor vehicle emissions are contributing to the violation, and which have specific transportation commitments included in the SIP/RIP to control mobile source emissions.

Areas of influence come in two versions, preliminary and final. The decision must be made as to whether transportation conformity should apply only to a final AOI (control region).

Transportation conformity could vary depending on where it is being applied. Thus transportation conformity could partially apply in some areas. Provision for a process to consider long-term impacts from transportation investments, of a forum for interagency and public debate, and perhaps of other functions could perhaps be achieved without applying transportation conformity's emissions analysis requirements. For example, VMT tracking, periodic emission projections, and interagency and public participation requirements (whether specifically tied to approval of short- and long-run transportation plans or individual projects) may provide some of the benefits of conformity without applying the entire, existing conformity process.

Where it makes sense to apply conformity in part depends upon the planning requirements for AOIs and AOVs. If the SIPs (or equivalent) do not have motor vehicle emissions projections and emission reduction targets that would serve as motor vehicle emissions budgets for conformity purposes, it may not make sense to apply conformity.

Who should make the decisions about where transportation conformity applies?

The options cover the range of federal and state agencies that are involved in air quality management and transportation planning: federal government; Regional Air Management Partnerships (RAMPs); AOI-level planning bodies; state government; either state government, RAMP, or AOI-level planning body. Option selection entails making choices about whether the decisions about applicability should be guided by national criteria, and the significance of geographical consistency if these decisions are made in a decentralized manner.

The specific options are the following:

EPA decides where transportation conformity applies,

state air agencies decide in consultation with EPA, local air authorities, and transportation agencies based on general criteria,

RAMPs, AOI-level planning bodies, or states decide, adhering to federally established criteria,

RAMPS or AOI-level planning bodies decide, adhering to national criteria developed by EPA in consultation with the U.S. Department of Transportation,

states decide in consultation with metropolitan planning organizations (MPOs), US DOT, and EPA,

states and local regulatory authorities decide, and

the agencies that are currently involved in the interagency consultation processes, following guidelines set by the Federal agencies.

If consistency and EPA's statutory authority to decide are important, centralization of decision making is preferred. The argument in favor of greatest decentralization—letting state and local regulatory agencies decide whether transportation conformity is necessary—stresses the ultimate responsibility of these agencies for compliance with air quality standards, and their role in determining the strategies to utilize and sources to control.

Should decisions about where transportation conformity applies be made separately for ozone and PM-2.5 areas?

The positions on this issue are connected to the previous issue dealing with who makes decisions. Therefore, the centralized-decentralized spectrum that appears in the discussion of who decides where transportation conformity applies has a parallel in the two positions on the desirability of separate application to ozone and PM-2.5 areas. One position is that the decisions should be separate, and it is presumed that the decisions will be made separately because of the differing characteristics of the pollutants and sources of emissions. The second position is that decisions about where transportation conformity applies should not be made separately for ozone and PM-2.5 areas.

Issue 2. How should transportation conformity be implemented if it is applied to areas that are much larger than metropolitan areas?

It is important to provide context for the five constituent issues relating to emission budget allocation and other matters into which this general issue may be separated. First, this implementation issue overlaps with the first issue: thus one option is to leave implementation entirely up to state and local regulatory agencies. This option is consistent with the view that state and local regulatory agencies also should decide where transportation conformity applies.

Second, depending on the extent to which one sees application of transportation conformity to rural or other nonmetropolitan areas as a departure from current applications, the need for new institutional arrangements and analytical tools will appear large or small. For example, in a state with rural nonattainment areas, where transportation conformity already applies, the same tools that enable SIPs to be developed (everything from "back-of-the-envelope" tools to travel demand modeling) can be applied to making rural transportation conformity determinations.

The implications of applying transportation conformity to a large area depend on how the responsibility for determining conformity is divided up among jurisdictions. Transportation conformity could apply in a large area but still be determined by individual states and metropolitan areas using subregional emission budgets. Alternatively, a central decision group and new institutional arrangements may be necessary if multiple states and metropolitan areas are to collectively determine conformity.

How should SIP budgets be allocated?

SIP budgets should be allocated on a subregional basis, just as the present conformity rule allows. Areas can and do establish subregional emissions budgets under the existing conformity process. Separate emissions budgets are established for different counties or planning areas within a nonattainment area. Similarly, if transportation conformity is applied to areas larger than a metropolitan area, emission budgets could be established for each metropolitan area, county, etc. provided the SIP (or equivalent) disaggregates emission projections to the appropriate level. In any particular area, either the institution that is responsible for regional air quality management or the states should determine the details of developing subregional emissions budgets.

It may not be necessary to have budgets in rural areas, but if such budget is included in the SIP, it should be allocated among different emissions sources by each state through the interagency process. For areas of violation which encompass larger than single state areas, some regional mechanism should be set up to establish a budget allocation process per pollutant.

Would the metropolitan transportation planning process still be the most appropriate focus of transportation conformity?

The metropolitan transportation planning process could still be the appropriate focus of transportation conformity within metropolitan areas. Statewide transportation plans and statewide transportation improvement programs (STIPs) could be used as the focus of transportation conformity for rural and nonmetropolitan areas, as they are under the existing transportation conformity process. If an entire state were subject to transportation conformity, the statewide planning process would almost certainly be an appropriate focus of conformity. For a combined AOI/AOV, there might be a parent group (all state departments of transportation and air quality agencies) which takes the various transportation improvement programs and projects and combines them.

If areas of violation cover relatively the same geographic boundaries as current metropolitan areas, the metropolitan planning process may be the conduit for carrying out the technical analyses for those areas having project specific long-range plans. If AOV's are substantially larger than current metropolitan boundaries, then the planning process is not the appropriate focus for conformity.

If transportation conformity is applied in rural areas, in view of limitations on analytical tools (travel demand models and MOBILE model), how could it be applied?

Presumably, transportation conformity determinations (if required) in rural areas would use similar data and tools as the SIP. Under the existing transportation conformity process, rural areas have almost maximum flexibility in their regional emissions analysis techniques. Therefore, rural areas should be able to perform emissions analyses at the level of detail and sensitivity appropriate to the available data. If it is not possible to determine the emissions impacts of transportation investments in rural areas, perhaps transportation conformity should not apply.

It may be helpful to provide guidance to rural areas to assist with choice of emissions analysis techniques, including a shortened test for demonstrating conformity. Options for the latter include a crude build/no build comparison, transit availability, car pool options, rail availability, and land use.

One approach to transportation conformity would be to allow states/regions to develop self-certification processes through which Federal Agencies would provide technical assistance and certification reviews. At a minimum, this concept should be tested within rural areas or areas of influence. Another approach to conformity in rural areas would be to compare transportation plans to SIPs/RIPs to ensure transportation commitments included in the SIP or RIP are met. It may also be appropriate to establish di minimis levels for emissions in rural areas.

Demonstration of conformity for rural areas or areas that go beyond the metropolitan planning boundaries may have to be based on less rigorous, more qualitative goals or performance measures. It would be inappropriate for conformity to drive rural areas into an overly prescriptive planning process.

In view of the multiple political jurisdictions that are likely to be covered by areas of influence, how should interagency consultation and conflict resolution for transportation conformity be structured?

If subregional emissions budgets are established and these subregions can determine conformity relatively independently, the problem of multiple political jurisdictions may not be overwhelming. If each state has its own SIP, each state would have its own emissions budgets, and conformity determinations would not necessarily routinely require multistate interactions.

There are currently many nonattainment areas in the country that cross state boundaries or MPO boundaries, so discussion of interagency consultation and conflict resolution could be informed by examining how these areas address these issues. The Clean Air Act Amendments of 1990 in section 7504 address nonattainment area planning, including multistate planning in the case of interstate nonattainment areas, and the existing conformity rules contain a section on consultation and conflict resolution. Interagency coordination is expanded on and clarified by the individual states. There are specific procedures for consultation between agencies and a final level of resolution by the governor. If one anticipates that representatives from AOVs will have opinions which differ from the representatives from AOIs, then a central decision group will be needed for each AOI.

One option is to apply the existing structure for interagency coordination to interstate transportation conformity, and to require EPA approval of final conformity determinations. Another option is to require states and other stakeholders to develop processes for consultation and conflict resolution. The latter could involve a new institutional arrangement to make transportation conformity determinations for interstate situations.

A third option applies to areas that affect multistate jurisdictions: the highest ranking officials of the organizational structure that parallels how emission inventories are structured and budgets allocated should be called in to handle dispute resolution. Federal agency officials could serve as facilitators. Similar considerations will have to be given in the SIP development process.

What role should tribes have in the transportation conformity process after promulgation of the new/revised NAAQS?

Issue 3. When should transportation conformity be required for the new/revised standards?

The answer to this question depends in part upon how one views the purpose of transportation conformity. If one views transportation conformity as a process to ensure that a SIP's emissions reductions are achieved, it may not make sense to require conformity before the SIP has determined what the motor vehicle emissions reductions should be. Seen in this way, conformity does not itself achieve emissions reductions, and therefore is not an appropriate mechanism for achieving progress during SIP development. However, if one views transportation conformity's purpose as preventing growth in motor vehicle emissions that would complicate attainment of the standards, one could argue that it is appropriate to apply conformity before SIPs are approved in order to prevent or limit growth in motor vehicle emissions.

One option is not to require transportation conformity before SIPs are approved.

If conformity is to be applied before SIPs are approved, two implementation issues must be resolved. Timing is one issue. The other issue is the nature of the conformity test.

The timing issue refers to setting the date for starting the transportation conformity requirement during SIP development. The options are:

date of preparation of an emission inventory which shows that mobile sources are a significant contributor to an identified or projected air quality problem,

date of RAMP creation,

date of final AOI designation,

date of regionally integrated plan (RIP) preparation,

date of control-strategy SIP submittal, and

date of SIP approval.

The timing of transportation conformity during SIP development must be coordinated with the timing of the other activities on which transportation conformity is dependent: decisions about where transportation conformity applies, definition of AOVs and AOIs, and creation of institutional arrangements for one or more functions—regional air quality planning, interagency coordination, and conflict resolution.

Fundamentally, demonstration of conformity requires a comparison of emissions under different scenarios. The options for the interim test are:

build/no-build test,

freeze motor vehicle emissions at the level of some prior year (e.g., year of designation or year in which an emissions inventory indicates that mobile sources are a significant contributor), and

require a specific percentage reduction from a specified baseline.

When a control-strategy SIP is submitted to EPA with proposed emissions budgets, the budget test could constitute an additional criterion for demonstrating conformity. Upon EPA approval, the interim test would be dropped.

There are practical difficulties associated with applying conformity before RIPs or SIPs have been submitted because these plans will help inform what type of data should be used, how sophisticated the transportation modeling needs to be, how responsibility for determining conformity should be allocated among political jurisdictions, etc. In addition, because conformity depends upon interagency consultation, it could be difficult to apply conformity before institutional mechanisms such as RAMPs have been established.

Another practical difficulty which may arise stems from uncertainties in emissions inventories, in particular, PM-2.5 emission factors and estimates of rural emissions. One position is that estimates of PM-2.5 emissions and rural emissions are inadequate for the purposes of transportation conformity. The PM-2.5 emission factors are critical in the modeling of mobile source emissions. Uncertainty in these factors will impact not only the demonstration of transportation conformity but also the development of the SIP against which conformity must be demonstrated. It is critical that accurate emissions factors be developed. Lack of estimates of rural emissions will also significantly affect both the SIP development and the transportation conformity process. Uncertainties in emissions factors make it impossible to develop the SIP and make the conformity determination.

The other position is that the uncertainties are not especially significant. As with any data used for planning purposes, we must make do with what we have. The PM-2.5 emission factors and estimates of rural emissions are the same data that we will use for developing SIPs; if these data are sufficient for SIP development, they are sufficient for the purposes of transportation conformity. Although the uncertainties in the PM-2.5 emission factors will cause some inaccuracies, it is important to start the process. An iterative process which seeks continuing data improvement should make the findings increasingly accurate. In the meantime, sharing common forecasting methods should move air quality and transportation plans in a common and good direction.

If transportation conformity does not apply until SIPs have been approved, remaining uncertainties about PM-2.5 would not significantly interfere with application of transportation conformity. Transportation conformity must demonstrate consistency with the SIP, and consistency can be tested even if the emission factors in the SIP are subject to uncertainty.

Areas that have never developed emission inventories not only need time to develop an inventory, but also to roll the inventory process into the transportation planning process. Experienced areas have worked out many bugs in integrating transportation and air quality planning and should be given enough time to transition to a new approach in a logical sequence within the transportation planning process rather than making an abrupt switch. Doing air quality out-of-step with the transportation planning process weakens the credibility of transportation conformity as something other than an arbitrary numbers game. Enough time must be allowed for all of the sequential steps in the process to happen sequentially. In some areas, experience with parallel tracking shows that tracks often don't merge effectively at the end. The transition to a new transportation conformity process should be as smooth as possible.

Issue 4. Should the scope of transportation conformity be expanded to facilitate more comprehensive intermodal planning, e.g, interplay between rail and truck transportation?

One option is not to expand the scope of transportation conformity to facilitate more comprehensive intermodal planning. Intermodal planning has nothing to do with transportation conformity and there is no way to connect them. Conformity does not lend itself to these considerations.

The other option is to facilitate as much as possible comprehensive intermodal planning, in particular, planning multimodal transportation systems which reduce air pollutant emissions. Comprehensive intermodal planning has several prerequisites. 1) U.S. DOT must integrate planning for these modes with roadway and transit planning. 2) Tools must be available to perform technical analyses. 3) MPOs must have effective authority over emissions from nonroad sources, and they must be held accountable for compliance with transportation control measures (TCMs) applying to nonroad sources.

Issue 5. Should transportation conformity relate to reasonable progress requirements under a regional haze rule?

Definition of Terms

Area of Violation (AOV) The AOV is the area which is determined to be violating the NAAQS. Class I areas will be treated in the same manner as AOV's for the purposes of defining AOI's and developing plans. Contrary to the current nonattainment designation process, an AOV is not necessarily assumed to be responsible for the observed violation. Thus, designation of an AOV does not carry with it automatic control requirements for the designated area, as is currently the case for a nonattainment area. However, the initial presumption is that the AOV will be a part of the preliminary AOI and final AOI. This presumption can be rebutted only upon a clear and convincing demonstration that anthropogenic sources in the AOV are not contributing to the violations being experienced. (Process for making the demonstration to be defined later).

Area of Influence (AOI) An AOI is a geographical area containing anthropogenic and natural sources which contribute to Areas of Violation (AOV). The identification of AOIs is divided into two phases:

Phase 1 - Preliminary AOI The Preliminary AOI is the area which contains an adequate array of sources to prepare a Regionally Integrated Plan (RIP). Inclusion within a Preliminary AOI does not mean that a location will necessarily be subject to regulation.

Phase 2 - Final AOI The Final AOI is the area in which regulatory control of emissions will be needed to bring an AOV back into attainment and ensure maintenance of the standards. The Final AOI is synonymous with a control region.

Regionally Integrated Plan (RIP) This has been referred to as a "spatially integrated plan (SPIP)" in earlier versions of the FACA Regional Partnerships/AOI issue paper. A RIP is prepared for a preliminary AOI. A RIP will define:

•	the Final AOI/control region,

•	in general terms, what level of control should be applied in the various portions of the AOI,

•	where transportation conformity should apply,

•	the structure and type of market-based incentives programs (where appropriate)

•	New Source control recommendations, and

•	other elements as appropriate.

The RIP is a set of recommendations to EPA and is to serve as the basis upon which EPA can develop SIP and TIP calls to the individual states and tribes. The RIP is not enforceable on its face. The RIP may also contain recommendations to EPA for action at the national or subnational level.

State Implementation Plan (SIP) A State implementation plan is a plan submitted by individual States to reduce emissions consistently with the regionally integrated plan. It contains specific measures and identifies mechanisms by which the measures are enforceable by that State.