Transportation Conformity Under the Clean Air Act

Congressional research reportMay 21, 2015

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Transportation Conformity Under the Clean

Air Act

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May 21, 2015

Congressional Research Service

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R44050

Transportation Conformity Under the Clean Air Act

Summary

Under the Clean Air Act, areas that have not attained one or more of the six National Ambient Air

Quality Standards (currently more than 100 areas with a combined population of 143 million)

must develop State Implementation Plans (SIPs) providing for implementation, maintenance, and

enforcement of the NAAQS. The act requires that, in these areas, federal agencies not engage in,

approve, permit, or provide financial support for activities that do not “conform” to the area’s SIP.

Although a wide range of federal funding and programs is subject to conformity, it is

transportation planning (and ultimately highway funding) that is most commonly affected. Before

a new transportation plan or transportation improvement program (TIP) can be approved by the

Federal Highway Administration or Federal Transit Administration or a new non-exempt project

can receive federal funding in a nonattainment area, a regional emissions analysis must generally

demonstrate that the projected emissions from the entire transportation system, including the new

projects, are consistent with the emissions ceilings established in the SIP. While some express

concern at the potential impact of these conformity determinations in delaying or altering new

highway projects, others note that the process simply obligates the federal government to support

rather than undermine the legally adopted state plans for achieving air quality.

In the late 1990s and early 2000s, there were numerous lapses of conformity: 63 areas, in 29

states and Puerto Rico, had lapses between 1997 and 2003. In 2005, however, Congress amended

the Clean Air Act to provide a 12-month grace period to demonstrate compliance following an

area’s designation as nonattainment before conformity will lapse. Since 2007, only seven areas

have experienced a conformity lapse, despite the imposition of more stringent ambient air quality

standards for both ozone and particulate matter. All but one of the lapses since 2007 were

resolved within a year.

As Congress considers reauthorization of surface transportation programs this year, questions

have again been raised regarding the impact of conformity requirements, and whether the

Environmental Protection Agency’s (EPA’s) current proposal to strengthen the ambient air quality

standard for ozone will affect the number of areas required to make conformity determinations.

Particular concern has been expressed for rural areas that may never have been classified

nonattainment for an air quality standard before. The number of areas ultimately affected will

depend on numerous factors, including the level at which EPA sets the final ozone standard and

trends in emissions and weather in the period before EPA designates any new nonattainment

areas. Although these factors introduce elements of uncertainty in future projections, most rural

areas are unlikely to be designated nonattainment for the ozone standard, because they do not

have ozone monitors in place. In the few rural areas that have been designated nonattainment,

conformity needs only to be determined if there is a non-exempt transportation project that

depends on federal funding or approval—a rare occurrence. In addition, EPA’s conformity

regulations provide exceptions for areas with insignificant motor vehicle emissions, which may

facilitate the demonstration of conformity in any rural areas that will be designated

nonattainment.

This report explains the statutory conformity requirements, reviews the recent history of their

implementation, and examines how conformity requirements might affect areas designated

nonattainment for a revised ozone air quality standard.

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Transportation Conformity Under the Clean Air Act

Contents

Conformity: The Basics ................................................................................................................... 1

Transportation Conformity .............................................................................................................. 2

Projects That Can Advance During a Lapse .............................................................................. 3

Determining Conformity in a Rural Area ........................................................................................ 4

Experience of Areas That Fail to Meet Conformity Deadlines ........................................................ 4

Grace Periods............................................................................................................................. 4

Conformity Lapses .................................................................................................................... 5

Effect of a Lapse ........................................................................................................................ 7

Pre-1999 Conformity Lapses ..................................................................................................... 8

Atlanta ....................................................................................................................................... 8

Conformity’s Growing Reach? ........................................................................................................ 9

EPA’s 2015 Ozone NAAQS ........................................................................................................... 11

Legislation ..................................................................................................................................... 13

Tables

Table 1. Nonattainment Areas that Failed to Obtain a Conformity Determination by the

Applicable Deadline, 2007-2014 .................................................................................................. 5

Table 2. Nonattainment Areas That Experienced a Conformity Lapse, 2007-2014 ........................ 7

Table 3. Projected vs. Actual Counties Exceeding the 2008 Ozone NAAQS................................ 11

Contacts

Author Contact Information........................................................................................................... 13

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Transportation Conformity Under the Clean Air Act

his report explains the Clean Air Act requirement that federal departments and agencies

demonstrate that their activities—including projects that they fund—“conform” to state

plans for achieving air quality standards. The report explains the statutory requirements,

reviews the recent history of their implementation, and examines how conformity requirements

might affect areas designated “nonattainment” for a revised ozone air quality standard. The

Environmental Protection Agency (EPA) proposed such a revision in December 2014, and is

under court order to finalize its review by October 1, 2015.

Conformity: The Basics

Transportation conformity, which is required by Section 176(c) of the Clean Air Act (CAA), was

established by Congress as a means of insuring that federal actions, including the provision of

federal funds for transportation projects, not undermine air quality in areas that have not attained

national ambient air quality standards (NAAQS) and in areas that were nonattainment, but have

been redesignated as maintenance areas under CAA Section 175A. By potentially withholding

federal funds for non-conforming projects, conformity serves as an important stimulus for state

and local governments to assess potential air quality impacts of projects and, if necessary, modify

them to assure that they not interfere with progress toward or maintenance of clean air.

Under Section 176(c), departments and agencies of the federal government are prohibited from

engaging in, supporting or providing financial assistance for, licensing, permitting, or approving

any activity that does not conform to a State Implementation Plan (SIP) after such a plan has been

submitted and approved. SIPs are a key element in achieving CAA standards. Under the act,

depending on the NAAQS and the classification of the nonattainment area,1 states are required to

develop SIPs within 18 months to four years of EPA’s designation of an area as nonattainment.

In general, in areas that have not attained one or more of the six NAAQS2 established by EPA

(currently more than 100 areas with a combined population of 143 million3) the state must

develop a SIP providing for implementation, maintenance, and enforcement of the NAAQS. In

most cases, a SIP contains an inventory of existing emissions, projections of future emissions

(generally including a motor vehicle emissions budget), and an identification of measures that

will be taken to reduce the emissions in order to reach attainment by the statutory deadline.4

Deadlines vary, depending on the severity of the pollution, but generally a nonattainment area

must demonstrate that it is making annual emission reductions sufficient to reach attainment. (For

a more extended discussion of the requirements for nonattainment areas, see CRS Report

RL30853, Clean Air Act: A Summary of the Act and Its Major Requirements.)

“Classification” refers to the severity of the pollution: the ozone NAAQS, for example, classifies areas in one of five

categories (Marginal, Moderate, Serious, Severe, or Extreme) depending on the ozone concentrations monitored over a

three-year period.

The standards are for ozone, particulate matter, carbon monoxide, nitrogen dioxide, sulfur dioxide, and lead.

For a listing, see U.S. EPA, Green Book, Summary Nonattainment Area Population Exposure Report,

http://www.epa.gov/airquality/greenbook/popexp.html. Data as of January 30, 2015.

An important exception to this general rule, contained in CAA Section 182(a)(4), is that Marginal ozone

nonattainment areas (i.e., the nonattainment areas with monitored ozone concentrations closest to achieving the

standard) do not need to demonstrate that the SIP will attain the standard by the applicable attainment date, provided

that the SIP meets statutory requirements for an inventory of emissions, the imposition of Reasonably Available

Control Technology on stationary sources of emissions, requires permits for new or modified major stationary sources,

and implements statutory requirements for emissions offsets.

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Once an area has attained the NAAQS, it can be redesignated as a “maintenance” area if it revises

its SIP to demonstrate how it will maintain compliance over a 20-year period. Conformity

requirements apply to both nonattainment and maintenance areas.5

The act contains seven pages of detail regarding what constitutes a conforming project, and the

requirements are further elaborated in the Code of Federal Regulations at 40 C.F.R. Part 93. In

general, conformity to a SIP means that a proposed project or program “will not produce new air

quality violations, worsen existing violations, or delay timely attainment of the national ambient

air quality standards or delay interim milestones.”6

Transportation Conformity

Although a wide range of federal funding and programs is subject to conformity, it is

transportation planning (and ultimately highway funding) that is most commonly affected.

Transportation makes a substantial contribution to ambient concentrations of four of the six

NAAQS pollutants: ozone, carbon monoxide, nitrogen dioxide, and particulate matter.7 Before a

new transportation plan or transportation improvement program (TIP) can be approved by the

Federal Highway Administration or Federal Transit Administration or a new non-exempt project

can receive federal funding, a regional emissions analysis must generally demonstrate that the

emissions of these pollutants or their precursors8 projected from the entire transportation system,

including the new projects, are consistent with the emissions ceilings established in the SIP.9

Conformity must be demonstrated for the period ending on either the final year of the area’s long

range transportation plan, or at the election of the metropolitan planning organization (MPO),

after consultation with the air pollution control agency, the longest of:

•

the first 10 years of the transportation plan;

•

the latest year in the SIP that contains a motor vehicle emissions budget; or

•

the year after completion of a regionally significant project.10

The number of counties required to demonstrate conformity because they are in maintenance areas can be substantial.

There are not yet any such areas for the 2008 ozone standard (nonattainment areas themselves were designated less

than three years ago), but for the preceding (1997) ozone NAAQS, 249 counties with 64 million people were

designated as maintenance areas, in addition to the 186 counties with 101 million people that are still classified

nonattainment.

U.S. EPA, “Transportation Conformity Rule Amendments: Flexibility and Streamlining,” Final Rule, 62 Federal

40 C.F.R. 93.102(b)(1) limits the applicability of transportation conformity requirements to these four NAAQS

pollutants.

Both ozone and particulate matter form in the atmosphere as the result of chemical reactions involving precursor

emissions: ozone, for example, forms when volatile organic compounds and nitrogen oxides react in the presence of

sunlight. Precursor pollutants are identified in 40 C.F.R. 93.102(b)(2).

CAA Section 176(c)(2)(A). As described below, in “Determining Conformity in a Rural Area,” if the SIP

demonstrates that regional motor vehicle emissions are an insignificant contributor to the area’s air quality problem, the

area is not required to conduct a regional motor vehicle emissions analysis to demonstrate conformity.

The authority to shorten the conformity horizon, as described in these three bullets, was added by Section 6011(c) of

P.L. 109-59 in 2005, but no MPO has elected to use it.

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Conducting this analysis can involve federal, state, regional, and local transportation and

environmental planners. Ultimately, the Federal Highway Administration and Federal Transit

Administration make conformity determinations for the transportation plan, TIP, and/or project.

The conformity determinations are based on the most recent estimates of emissions, population,

employment, travel, and traffic congestion provided by a variety of agencies. Combining these

data, the MPO or state DOT must estimate vehicle miles traveled and emissions, generally by

using an approved EPA mobile source emissions model. These models are periodically updated to

reflect the current mix of vehicles and their emission characteristics.

To reflect the changing nature of both economic and environmental inputs, both the statute and

the regulations require that a nonattainment area’s long-range Transportation Plan and its TIP

demonstrate conformity at least every four years.11 The statute and regulations also require that

MPOs re-determine conformity of transportation plans and programs not later than two years

after approval of a new State Implementation Plan or motor vehicle emissions budget.12 In

practice, many urban areas obtain a new determination that their TIP conforms on an annual

basis.

Projects That Can Advance During a Lapse

In the absence of conformity, the regulations provide that a limited set of exempt projects can go

forward.13 The list includes 20 categories of highway safety projects, rehabilitation and

reconstruction of transit facilities, purchase of replacement buses and rail cars, noise attenuation

projects, and pedestrian and bicycle facilities. It does not include most new transit or highway

projects, however. EPA’s Office of Transportation and Air Quality (OTAQ) defined the exempt

projects as those that are “air quality neutral”—that is, they neither improve nor degrade air

quality.

In addition to projects that are exempt by regulation, projects that were already approved and

funded in the previous TIP may continue to be funded during a conformity lapse, provided that

approval is not sought for a new phase of the project. Phases of a project include, among others,

determination of environmental impacts under the National Environmental Policy Act, right-ofway acquisition, final design, and construction. Activities within each of those phases can

continue for projects that were found to conform in the previous TIP.

Transportation Control Measures (TCMs) listed in an approved State Implementation Plan are

also allowed to proceed during a conformity lapse. These projects can include programs for

improved public transit, construction of HOV (high occupancy vehicle) lanes, traffic flow

improvement programs, fringe parking, idling reduction programs, and pedestrian facilities.14

CAA Section 176(c)(4)(D)(ii); 40 C.F.R. 93.104(b)(3).

CAA Section 176(c)(2)(E); 40 C.F.R. 93.104(e).

The kinds of projects that are exempt are listed in 40 CFR 93.126.

A full list of TCMs is provided in Section 108 of the Clean Air Act.

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Determining Conformity in a Rural Area

In general, the statute and regulations assume that projects requiring a conformity determination

will be located in urban or suburban areas, because most nonattainment areas have an urban or

suburban core. But there are some nonattainment areas that are not urban or suburban. These

areas would only need to demonstrate conformity if they had a non-exempt project that required

federal funding or approval—a rare occurrence. Unlike areas with MPOs, they are not required to

demonstrate conformity every four years.

For the few rural areas that may have a federally funded project, EPA has developed separate

procedures in 40 C.F.R. 93.109(f) that may deal with conformity. The section, which addresses

“areas with insignificant motor vehicle emissions,” states:

... an area is not required to satisfy a regional emissions analysis ... for a given

pollutant/precursor and NAAQS, if EPA finds through the adequacy or approval process that

a SIP demonstrates that regional motor vehicle emissions are an insignificant contributor to

the air quality problem for that pollutant/precursor and NAAQS. The SIP would have to

demonstrate that it would be unreasonable to expect that such an area would experience

enough motor vehicle emissions growth in that pollutant/precursor for a NAAQS violation to

occur. Such a finding would be based on a number of factors, including the percentage of

motor vehicle emissions in the context of the total SIP inventory, the current state of air

quality as determined by monitoring data for that NAAQS, the absence of SIP motor vehicle

control measures, and historical trends and future projections of the growth of motor vehicle

emissions.

Most rural areas are unlikely to need to demonstrate conformity: the absence of monitoring data

will mean that EPA cannot designate a rural area nonattainment in most cases. A nonattainment

designation is based on the availability of three years of quality-controlled data from EPAcertified monitors. Approximately 814 U.S. counties (26% of the total) had ozone monitors

reporting data to EPA in 2013; 2330 counties (74%), generally in less-populated areas, had no

ozone monitoring.15 As a result, the majority of the nation’s counties are termed “unclassifiable”

by EPA, and are not subject to conformity.

Experience of Areas That Fail to Meet Conformity

Deadlines

Nonattainment areas that have not demonstrated conformity by the applicable deadline fall into

one of two groups: those in a grace period, and those in a conformity lapse.

Grace Periods

In the 2005 surface transportation law,16 Congress amended Section 176(c) of the Clean Air Act

to provide that areas that do not make a conformity determination for a transportation plan or TIP

Office of Air Quality Planning and Standards, U.S. EPA, personal communication, May 1, 2015.

The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU), P.L.

109-59.

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by the applicable deadline are given a 12-month grace period to demonstrate compliance before

conformity will lapse.17 As shown in Table 1, since 2007, 34 areas in 18 states have used this

grace period. As a result of this, as well as cooperation between air quality and transportation

planners, all but seven areas in six states (Table 2) have been able to demonstrate conformity

without incurring a lapse.

Conformity Lapses

The experience of areas in the last decade was a marked change from the experience of areas

prior to the 2005 amendments. From 1997 to 2003, 63 areas in 29 states and Puerto Rico18 had

experienced a lapse, according to EPA. With a few notable exceptions,19 these areas were either

medium-size cities or they were suburban areas near some of the nation’s largest cities.

Table 1. Nonattainment Areas that Failed to Obtain a Conformity Determination by

the Applicable Deadline, 2007-2014

(The following 34 areas triggered a 12-month grace period under the provisions of CAA Section

176(c)(9).)

Nonattainment/

Maintenance Area(s)

Affected

Pollutant

Start Date of Lapse

Grace Period

Length of Lapse

Grace Period

New Castle County, DE/Cecil

County, MD

1997 ozone

4/16/2007

1 month

Christen County, KY

1997 ozone

7/7/2007

3 months

Montgomery, TN

1997 ozone

7/1/2007

7 months

Knoxville, TN

PM2.5

7/1/2007

5 months

Chattanooga, TN

PM2.5

7/1/2007

7 months

Great Falls, MT

3/22/08

12 months

Southern Portion of NJ MPO

1997 ozone

5/24/08

4 months

Memphis, TN

1997 ozone

3/23/08

1 week

Missoula, MT

PM10

6/7/08

1 year

Triad Area, NC

PM2.5

10/1/08

5 months

PM2.5 and 1997 ozone

8/1/08

1 month

1997 ozone

2/1/08

1 month

Steubenville-Wierton, OH-WV

Weeling, WV-OH

Section 176(c)(9).

Alabama, Alaska, California, Colorado, Connecticut, Delaware, Georgia, Idaho, Indiana, Kansas, Kentucky,

Louisiana, Michigan, Missouri, Montana, Nevada, New Hampshire, New Jersey, New Mexico, New York, North

Carolina, Ohio, Puerto Rico, Rhode Island, Tennessee, Texas, Utah, Washington, West Virginia, and Wisconsin. Since

1993, areas in 35 states have experienced a lapse: the 29 listed above, plus Maine, Massachusetts, Minnesota, Oregon,

Pennsylvania, and Virginia.

The Los Angeles area was out of conformity for two months in 1998, Houston for five months in 1999-2000, and the

Bay Area of California for two short stretches in 2002 and 2003. None of the other top 15 cities in population

experienced a conformity lapse. At the other end of the spectrum, about 15 relatively small cities, such as Great Falls,

MT, and Ashland, KY, experienced lapses.

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Nonattainment/

Maintenance Area(s)

Affected

Pollutant

Start Date of Lapse

Grace Period

Length of Lapse

Grace Period

Parkersburgh-Marietta, WV-OH

1997 ozone

2/1/2008

1 month

3/22/2008

1 year

Philadelphia-Wilmington-Atlantic

City, PA-NJ-MD-DE

1997 ozone

4/15/2009

2 weeks

Terre Haute, IN

1997 ozone

6/1/2009

4 weeks

Parkersburgh-Marietta, WV-OH

1997 ozone

2/1/2009

2 months

Fort Wayne, IN

1997 ozone

5/15/2009

3 weeks

Muncie, IN

1997 ozone

6/13/2009

1 month

Reno, NV

PM10

4/8/2009

3 months

Charlotte-Gastonia-Rock Hill,

NC-SC

1997 ozone

5/3/2009

1 year

Clarksville-Hopkinsville, TN-KY

1997 ozone

7/28/2009

9 months

6/29/2009

1 year

Louisville, KY-Southern IN MPO

1997 ozone

12/8/2009

11 months

Sussex County, DE

(WILAMPCO)

1997 ozone

2/17/2010

1 month

PM10

3/1/2010

9 months

St. Louis, MO

1997 ozone

6/29/2011

2 months

Birmingham, AL

1997 ozone

11/1/2011

1.5 months

Beaumont, TX

1997 ozone

9/25/2011

1 year

Yakima, WA

PM10

6/1/2011

10 months

Wheeling, WV

PM and 1997 ozone

3/20/2012

3.5 months

Evansville, IN

PM2.5

11/30/2012

1 year

Great Falls, MT

4/23/2013

1 year

1997 ozone

6/16/2013

1 year

Great Falls, MT

Billings, MT

Yuma, AZ

Huntington-Ashland, KY

Source: U.S. EPA, Office of Transportation and Air Quality, April 2015.

Notes: PM = particulate matter; PM10 = PM that is 10 microns or smaller in diameter; PM2.5 = PM that is 2.5

microns or smaller in diameter; CO = carbon monoxide.

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Table 2. Nonattainment Areas That Experienced a Conformity Lapse, 2007-2014

Nonattainment/

Maintenance Area(s)

Affected

Pollutant

Start Date of Lapse

Length of Lapse

Great Falls, MT

3/22/2009

1 month

Billings, MT

6/20/2010

1 day

Beaumont, TX

1997 ozone

9/25/2012

2 years, 5 months

Pinal County, AZ

PM10

7/2/2013

6 months

Evansville, IN

PM2.5

11/30/2013

6 months

Reading, PA (Berk County)

2008 ozone

7/20/2013

5 months

Huntington-Ashland, KY

1997 ozone

6/16/2014

10 months

Source: U.S. EPA, Office of Transportation and Air Quality, April 2015.

Notes: PM = particulate matter; PM10 = PM that is 10 microns or smaller in diameter; PM2.5 = PM that is 2.5

microns or smaller in diameter; CO = carbon monoxide.

Effect of a Lapse

Both before and after the addition of grace periods, most of the lapsed areas have returned to

conformity quickly. Since 2007, only two areas (Huntington-Ashland, KY, and Beaumont, TX)

have been in a lapse for more than six months. In the 1997-2003 period, of the 63 areas that

experienced a lapse, 40 conformed within six months.

Of the areas that lapsed for more than a year, few were major urban areas. The Government

Accountability Office (GAO), citing EPA conformity program managers, reported that “most of

these areas did not have pending new projects and, therefore, were not under time pressures to

resolve their lapse.”20

None of the lapsed areas actually lost transportation funding. DOT does not reduce the amount of

funding a state receives, but without a conforming TIP, only exempt projects, TCMs, and project

phases approved and begun in an earlier conforming TIP may be funded. Ultimately, when an

area develops a new conforming TIP, the projects in that TIP will become eligible to receive

funds.

Aside from the observations noted above, it is difficult to generalize about the experiences of

these areas. Each has, or had, its own special set of circumstances leading to the conformity lapse,

and the transportation agencies and EPA responded in numerous, often unique ways. Many of the

areas were allowed to demonstrate conformity by adopting additional emission reduction

measures, by using a newer approved emissions model, by updating data used in the models, or

by modifying the list of projects included in their TIP. In a 2003 survey, GAO found that, over the

U.S. GAO, Environmental Protection: Federal Planning Requirements for Transportation and Air Quality

Protection Could Potentially Be More Efficient and Better Linked, Report GAO-03-581, April 2003, p. 14. Hereinafter

referred to as “GAO Report.”

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previous six years, only five metropolitan areas had to change transportation plans in order to

resolve a conformity lapse.21

Pre-1999 Conformity Lapses

In general, until a March 1999 court decision,22 state and federal transportation agencies followed

a less stringent interpretation of the act’s requirements that allowed numerous projects to be

funded and to continue through design and construction on the grounds that they had been

approved and thus “grandfathered” prior to the lapse. In March 1999, however, the U.S. Court of

Appeals for the D.C. Circuit struck down the grandfather clause. Since then, EPA and DOT have

implemented more stringent requirements, through revised regulations.23

Atlanta

Atlanta is generally considered the “poster-child” for the most extreme effects of a lapse in

conformity. Atlanta was classified as a Serious ozone nonattainment area under the one-hour

ozone standard that EPA promulgated in 1979.24 While it had implemented numerous controls to

reduce emissions and improve air quality, it continued to exceed the 1979 ozone standard as of

the late 1990s.

The Atlanta area is considered a prime example of sprawl development. In a 2001 report, the

Atlanta Regional Commission (ARC), the federally designated MPO, found that, among 66 urban

areas with populations greater than 500,000, Atlanta ranked 4th in land area, but 56th in population

density. In large measure because of this sprawl, the Atlanta area also ranked 4th in the nation in

vehicle miles traveled per capita.25 Vehicle emissions were, therefore, major contributors to the

area’s ozone nonattainment.

At the time of the D.C. Circuit’s March 1999 conformity decision, the Atlanta metropolitan area

was already in the second year of a conformity lapse. (The lapse began January 17, 1998, and

lasted until July 26, 2000.) Initially, U.S. DOT had allowed the continued funding of numerous

highway projects in Atlanta, despite the lapse in conformity, on the grounds that they were

grandfathered. In January 1999, the Sierra Club and two local environmental groups filed suit,

however, challenging 61 of the grandfathered projects, contending that they should not have been

allowed to proceed except as part of a conforming TIP.26 In light of the D.C. Circuit opinion, the

GAO Report, p. 4.

Environmental Defense Fund v. EPA, 167 F.3d 641 (D.C. Cir. 1999).

A chronological listing and links to EPA conformity rules can be found at http://www.epa.gov/otaq/stateresources/

transconf/conf-regs-c.htm.

In the 1990 Clean Air Act Amendments (P.L. 101-549), Congress required that ozone nonattainment areas be

classified as Marginal, Moderate, Serious, Severe, or Extreme, depending on the degree to which monitored ozone

concentrations exceeded the ozone standard. For a more extended discussion of the categorization scheme, see CRS

Report RL30853, Clean Air Act: A Summary of the Act and Its Major Requirements, by (name redacted) and

(name redacted), pp. 4-7.

Data are from Atlanta Regional Commission, Highlighting Regional Progress: 2001 Annual Report, p. 5,

http://www.atlreg.com/aboutus/AnnualReport2001.pdf.

Georgians for Transportation Alternatives v. Shackelford, No. 99-CIV-0160 (N.D. Ga., filed Jan. 22, 1999).

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parties reached a settlement agreement in June 1999, under which many of the grandfathered

projects were halted, but 17 were allowed to go forward.

The heart of the Atlanta settlement was a new Interim Transportation Improvement Program (or

ITIP). When conformity lapsed in January 1998, ARC had developed and received approval for

an ITIP, which included the various grandfathered projects. In light of the litigation and D.C.

Circuit decision, ARC developed a second (and ultimately a third) ITIP that the state and federal

transportation departments, and EPA, as well as the environmental groups that had filed suit

agreed could go forward during the lapse of conformity.

Because they followed the D.C. Circuit decision and were themselves the product of settlement

negotiations in a separate suit, the second and third Atlanta ITIPs are the best examples of what is

allowed during a conformity lapse. These ITIPs, according to ARC, included only three kinds of

projects: projects that were exempt under 40 CFR 93.126 (discussed above, on page 3);

Transportation Control Measures; and a small group of projects that had received necessary

approvals or funding and were allowed to continue to the completion of the phase that they were

in.27 In all, about $700 million in projects that would have expanded highway capacity were

stopped.

Ultimately, in July 2000, ARC received approval for a new Transportation Improvement Program.

The new program de-emphasized new highway capacity. Instead, 40% of its funds were dedicated

to transit, 10% to bicycle and pedestrian facilities, 21% to safety measures and bridge and

intersection improvements, and 26% to highway capacity.28

Besides the new TIP, an important result of Atlanta’s conformity lapse was the development of

the Georgia Regional Transportation Authority, whose Board included the heads of six state

agencies as well as nine members appointed by the Governor. The authority was widely credited

with improving coordination among transportation, planning, and environmental officials.

Thus, although conformity requirements disrupted Atlanta’s transportation planning, they appear

to have served their intended function, forcing transportation and environmental officials to

confer regarding the environmental impacts of transportation programs before and during major

planning, design, and construction decision points and reorienting the area’s transportation

planning to a more multi-modal approach than the previous one, which relied heavily on new

highway capacity. Not all parties were happy with these results, of course, but it would be hard to

argue that the revisions violated the intent of the conformity requirements.

Conformity’s Growing Reach?

When CRS wrote on transportation conformity in 2004, the report29 stated that the impact of

conformity requirements might be expected to grow in the next few years for several reasons.

First, the growth of emissions from sport utility vehicles and other light trucks and greater than

Personal communication, Chris Chovan, Atlanta Regional Commission, August 2002.

See “DOT, EPA Clear Atlanta Transportation Plan, Freeing $700 Million in U.S. Highway Money,” Daily

Environment Report, July 27, 2000, p. A-14.

CRS Report RL32106, Transportation Conformity Under the Clean Air Act: In Need of Reform?, by (name red

acted).

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Transportation Conformity Under the Clean Air Act

expected increases in vehicle miles traveled appeared to be making it more difficult to

demonstrate conformity. Second, recent court decisions (noted above) had tightened the

conformity rules, making it more difficult to grandfather new projects. And third, the

implementation of more stringent air quality standards for ozone and particulate matter (PM) in

2004 would mean that additional areas would be subject to conformity, many for the first time.

Thus, the report concluded, numerous metropolitan areas would face a temporary suspension of

highway and transit funds unless they imposed sharp reductions in vehicle, industrial, or other

emissions. CRS was not alone in this expectation: about one-third of local transportation planners

responding to a GAO survey expected to have difficulty demonstrating conformity in the future.30

Instead, in the time period since then, for a variety of reasons, conformity appears to have been a

routine matter in most areas. What happened? A combination of higher fuel cost and the

economic recession led to a reduction in vehicle miles traveled and a smaller share of new vehicle

sales in the SUV and light truck categories. New emission control requirements for motor

vehicles, power plants, and other sources also kicked in, substantially reducing emissions of

ozone-forming compounds.31

Air quality data from before and after the promulgation of EPA’s 2008 ozone NAAQS show the

effect of these factors (see Table 3). In July 2007, when EPA proposed lowering the ozone

NAAQS from what was effectively 84 parts per billion (ppb)32 to 75 ppb, the agency identified

398 counties33 with monitoring data exceeding the proposed standard, based on the most recent

three years of data (2003-2005).34 The Regulatory Impact Analysis that accompanied the final

standard in March 2008, using data for 2004-2006, identified 345 counties exceeding the 75 ppb

NAAQS. By May 2012, when the nonattainment areas were actually designated, the number of

counties in nonattainment had fallen to 232, based mostly on data for 2008-2010.35

GAO Report, previously cited, p. 4.

Tighter vehicle emission and fuel standards for light duty vehicles (“Tier 2” standards) were phased in from 2004 to

2009. Emission and fuel standards for highway diesel trucks were phased in beginning in 2006. Power plants were

subject to the Clean Air Interstate Rule, which reduced NOx emissions, beginning in 2010.

The standard, prior to 2008 was 0.08 parts per million. Because of rounding conventions, areas with concentrations

of 84 ppb or less were considered to be in attainment.

See http://www.epa.gov/groundlevelozone/pdfs/20070621_maps.pdf. With a few exceptions (notably in Wyoming

and western Colorado), a map of the 398 counties looks remarkably similar to the December 2014 map of counties that

currently exceed the proposed December 2014 revision of the ozone NAAQS. Compare to Figure 2 in CRS Report

R43092, Ozone Air Quality Standards: EPA’s 2015 Revision, by (name redacted) .

Compliance with the ozone NAAQS is based on the average of the fourth highest monitored concentration in each

year, averaged over the most recent three-year period.

U.S. EPA, “Nonattainment Designations for the 2008 Ozone Standards—Counties by State, April 30, 2012 and May

31, 2012,” at http://www.epa.gov/groundlevelozone/designations/2008standards/final/finaldes.htm. The list is

comprised of 192 full counties and 40 partial counties.

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Table 3. Projected vs. Actual Counties Exceeding the 2008 Ozone NAAQS

Date

Event

Monitored Perioda

Number of Counties

with Monitors

Exceeding the

Proposed or Final

75ppb Standard

July 2007

proposal of 75 ppb NAAQSb

2003-2005

398

March 2008

promulgation of 75 ppb NAAQS

2004-2006

345

May 2012

designation of nonattainment areas

2008-2010c

232

Source: U.S. EPA.

Attainment determination is based on the average of the annual 4th highest monitored eight-hour ozone

concentration for the most recent three-year period.

EPA proposed to set the primary NAAQS somewhere in the range of 70 to 75 ppb. The number of

counties exceeding a 70 ppb standard as of July 2007 was 533.

Some area designations were based on 2009-2011 data.

As EPA stated in 2012, in the materials accompanying the formal designations:

Air quality continues to improve across the nation as a result of successful federal, state and

local pollution reduction efforts. EPA designated 113 areas as not meeting the 1997 ozone

standards set at 84 parts per billion. Less than half that number are not meeting the 2008

standards. In addition, many of the areas designated today cover a smaller geographic area

than the previous standards.... Only three areas in two states (California and Wyoming) have

not been nonattainment for previous ozone standards. Wyoming is the only state that has not

previously had an area designated nonattainment for ozone.36

EPA’s 2015 Ozone NAAQS

EPA is currently considering a more stringent NAAQS for ozone again: a revised NAAQS was

proposed in December 2014, and EPA is under court order to make a final decision by October 1,

2015.37 During the public comment period on the proposed rule, concerns regarding the extent of

ozone nonattainment and thus the burden of demonstrating conformity have been raised, much as

they were when EPA proposed previous NAAQS revisions.38 In the support documents that

accompanied the December 2014 proposal, EPA identified 358 counties currently exceeding a

proposed 70 ppb standard, using data for 2011-2013—or 558 counties if the NAAQS is set at 65

ppb.39

U.S. EPA, “National Air Quality Standards for Ozone, Final Designations—Questions and Answers,” at

http://www.epa.gov/airquality/ozonepollution/designations/2008standards/final/qandafinal.htm. The 113 areas

designated nonattainment contained all or parts of 474 counties.

For information on the proposed standard, see CRS Report R43092, Ozone Air Quality Standards: EPA’s 2015

Revision.

See, for example, National Association of Manufacturers, “Understanding Ground-Level Ozone Policies,” February

2015, at http://www.nam.org/Newsroom/Multimedia/Understanding-Ground-Level-Ozone-Policies/.

The list of counties is at http://www.epa.gov/air/ozonepollution/pdfs/20141126-20112013datatable.pdf.

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Because of continuing air quality improvements, the number of counties with monitors exceeding

the standard is almost certain to decline before the nonattainment areas are formally designated.

At the earliest, designation of nonattainment areas will occur in late 2017.40

•

By that time, new (Tier 3) standards for motor vehicles and their fuels will have

taken effect. In promulgating Tier 3 last year, EPA estimated that Tier 3 alone

would reduce ozone-forming emissions of NOx from motor vehicles by 10% in

2018.41

•

Beginning in 2015, power plants are required to reduce ozone-forming NOx

emissions, as a result of implementation of the Cross-State Air Pollution Rule

(CSAPR).42

•

The oil and gas industry, whose emissions of NOx doubled and whose VOC

emissions increased fivefold between 2005 and 2013,43 are now subject to New

Source Performance Standards that will reduce their emissions of ozone-forming

volatile organic compounds (VOCs).44

•

Standards for stationary engines used for irrigation pumps and backup power

supplies, which went into effect in 2013, will reduce emissions of both VOCs and

NOx.45

These and other emission standards are likely to reduce the number of counties with ambient

concentrations above the proposed new ozone standard (as compared to the list based on 20112013 monitoring data that was included in the support documents for EPA’s proposed rule). In

areas that will be formally designated nonattainment, the emission standards cited above will

facilitate the demonstration of conformity.

EPA’s analysis projects the effects of these standards on ozone nonattainment areas. The agency’s

modeling shows only nine counties outside of California exceeding a 70 ppb ozone NAAQS in

2025, without any emission control measures additional to those already promulgated. A 65 ppb

standard imposes a somewhat greater burden, but in that case, too, the modeling shows most areas

The Clean Air Act, in Section 107(d)(1)(B), requires the EPA Administrator to designate nonattainment areas within

two years of promulgating a NAAQS revision, with the possibility of up to a one-year extension in case of insufficient

information. Thus, if there is no extension, designation of ozone nonattainment areas would be due by October 1, 2017.

Following promulgation, the designations must be published in the Federal Register, with an effective date anywhere

from 30 to 120 days after publication occurs. This would bring the effective date to late 2017 or early 2018. In practice,

the process often takes longer. Following the 2008 ozone NAQS revision, EPA took four years to designate

nonattainment areas, as the result of a decision to reconsider the revised NAAQS. Following the 1997 revision, because

of legal challenges, the process took seven years.

U.S. EPA, Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards Final

Rule, Regulatory Impact Analysis, p. ES-7, at http://www.epa.gov/otaq/documents/tier3/420r14005.pdf.

Because of a stay issued by the D.C. Circuit Court of Appeals, the original CSAPR implementation dates were

delayed from 2012 and 2014, to 2015 and 2017. See http://www.gpo.gov/fdsys/pkg/FR-2014-12-03/pdf/201428286.pdf. CSAPR will reduce NOx emissions by nearly 200,000 tons annually, when fully implemented in 2017. See

http://www.epa.gov/crossstaterule/pdfs/CSAPRPresentation.pdf.

U.S. EPA, National Emissions Inventory (NEI) Air Pollutant Emissions Trend Data, at http://www.epa.gov/ttn/chief/

trends/.

See CRS Report R42986, An Overview of Air Quality Issues in Natural Gas Systems, by (name redacted)

See http://www.epa.gov/ttn/oarpg/t3/fact_sheets/rice_neshap_fr_fs081010.pdf and http://www.epa.gov/ttn/oarpg/t3/

fact_sheets/rice_neshap_fs_021710.pdf.

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Transportation Conformity Under the Clean Air Act

reaching attainment without additional controls.46 This would seem to imply that EPA expects

most areas would not have difficulty demonstrating conformity despite a more stringent ozone

standard.

Legislation

If Congress were to consider legislation to amend the transportation conformity requirements, the

most likely vehicle for doing so would be legislation reauthorizing the surface transportation

program. Funding expires at the end of May 2015. As of this writing (mid-May), reauthorization

legislation had not begun to move, although there has been much talk of a temporary extension of

funding. It is generally thought that any short-term extension would not include policy provisions.

It is unclear, at this time, when Congress may consider broader reauthorization legislation.

The following bills have been introduced that would have indirect effects on conformity

determinations for ozone nonattainment areas by modifying the dimensions of nonattainment

areas or preventing or delaying EPA’s proposed strengthening of the ozone NAAQS:

•

H.R. 1044 would require each state to revise the boundaries of ozone and carbon

monoxide nonattainment areas that include entire metropolitan or consolidated

metropolitan statistical areas, to exclude counties that are not in violation of the

NAAQS, as determined by air quality monitoring;

•

H.R. 1327 / S. 640 would delay the review and revision of the ozone NAAQS for

three years and require future reviews at 10-year rather than 5-year intervals;

•

H.R. 1388 / S. 751 would prohibit a more stringent standard until at least 85% of

the counties in nonattainment areas as of July 2, 2014, attained the current

standard, and would require EPA to consider feasibility and cost in setting an

ozone NAAQS, among other provisions; and

•

H.R. 2111 would provide that no funds made available under any act may be

used by EPA to implement any ozone standard promulgated after its date of

enactment.

Author Contact Information

(name redacted)

Specialist in Environmental Policy

/redacted/@crs.loc.gov, 7-....

See U.S. EPA, “Counties Projected to Violate the Primary Ground‐level Ozone Standard, Model projections for

2025,” at http://www.epa.gov/air/ozonepollution/pdfs/20141126-2025datatable.pdf.

Congressional Research Service

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