Rural Conformity:

A Survey of Practice

Requested by:

American Association of State Highway 

and Transportation Officials (AASHTO)

Standing Committee on Planning

	

Prepared by:

ICF Consulting

9300 Lee Highway

Fairfax, Virginia 22031

In association with:

Sarah J. Siwek & Associates

The information contained in this report was prepared as part of NCHRP
Project 08-36, Task 28, National Cooperative Highway Research Program,
Transportation Research Board.  



Acknowledgement

This study was requested by the American Association of State Highway
and Transportation Officials (AASHTO), and conducted as part of National
Cooperative Highway Research Program (NCHRP) Project 08-36.  The NCHRP
is supported by annual voluntary contributions from the state
Departments of Transportation. Project 08-36 is intended to fund quick
response studies on behalf of the AASHTO Standing Committee on Planning.
 The report was prepared by ICF Consulting, with assistance from Sarah
J. Siwek and Associates.  The work was guided by a task group chaired by
Calvin Legget, North Carolina Department of Transportation which
included Cecilia Ho, Federal Highway Administration; David Hyder, North
Carolina Department of Transportation; Meg Patulski, U.S. Environmental
Protection Agency; and Lynn Soporowski, Kentucky Transportation Cabinet.
 In addition, Angela Spickard from the US Environmental Protection
Agency also provided extensive feedback on the methodology and draft
report.  Appendix B lists the many practitioners who provided the
substance of this report by describing their experiences with the rural
transportation conformity process.  The project was managed by Ronald D.
McCready, NCHRP Senior Program Officer.  

Disclaimer

The opinions and conclusions expressed or implied are those of the
research agency that performed the research and are not necessarily
those of the Transportation Research Board or its sponsors. This report
has not been reviewed or accepted by the Transportation Research Board's
Executive Committee or the Governing Board of the National Research
Council.  

Table of Contents

  TOC \o "1-2" \h \z    HYPERLINK \l "_Toc56334350"  1	Introduction	 
PAGEREF _Toc56334350 \h  1  

  HYPERLINK \l "_Toc56334351"  1.1	Background	  PAGEREF _Toc56334351 \h 
1  

  HYPERLINK \l "_Toc56334352"  1.2	Study Purpose	  PAGEREF _Toc56334352
\h  1  

  HYPERLINK \l "_Toc56334353"  1.3	Research Approach	  PAGEREF
_Toc56334353 \h  2  

  HYPERLINK \l "_Toc56334354"  1.4	Report Organization	  PAGEREF
_Toc56334354 \h  3  

  HYPERLINK \l "_Toc56334355"  2	An Overview of Transportation
Conformity Requirements and Isolated Rural Areas	  PAGEREF _Toc56334355
\h  4  

  HYPERLINK \l "_Toc56334356"  2.1	Types of Rural Areas	  PAGEREF
_Toc56334356 \h  4  

  HYPERLINK \l "_Toc56334357"  2.2	What Is Transportation Conformity?	 
PAGEREF _Toc56334357 \h  5  

  HYPERLINK \l "_Toc56334358"  2.3	Transportation Planning and
Conformity Requirements in Metropolitan Areas	  PAGEREF _Toc56334358 \h 
6  

  HYPERLINK \l "_Toc56334359"  2.4	Conformity Requirements for Donut
Areas	  PAGEREF _Toc56334359 \h  7  

  HYPERLINK \l "_Toc56334360"  2.5	Conformity Requirements for Isolated
Rural Areas	  PAGEREF _Toc56334360 \h  7  

  HYPERLINK \l "_Toc56334361"  3	State of the Practice	  PAGEREF
_Toc56334361 \h  15  

  HYPERLINK \l "_Toc56334362"  3.1	Frequency of Conformity Analysis	 
PAGEREF _Toc56334362 \h  15  

  HYPERLINK \l "_Toc56334363"  3.2	Role of State DOT and Local Agencies	
 PAGEREF _Toc56334363 \h  18  

  HYPERLINK \l "_Toc56334364"  3.3	Outcomes	  PAGEREF _Toc56334364 \h 
19  

  HYPERLINK \l "_Toc56334365"  3.4	Issues Encountered in the Conformity
Process	  PAGEREF _Toc56334365 \h  22  

  HYPERLINK \l "_Toc56334366"  3.5	Preparations for New Standards	 
PAGEREF _Toc56334366 \h  25  

  HYPERLINK \l "_Toc56334367"  4	Lessons Learned	  PAGEREF _Toc56334367
\h  27  

  HYPERLINK \l "_Toc56334368"  4.1	Transportation Staff Need to be
Involved in Development of the SIP	  PAGEREF _Toc56334368 \h  27  

  HYPERLINK \l "_Toc56334369"  4.2	Build Trust Between DOT and Air
Agency Staff	  PAGEREF _Toc56334369 \h  27  

  HYPERLINK \l "_Toc56334370"  4.3	Be Aware of Data Limitations and
Improvements to Address Them	  PAGEREF _Toc56334370 \h  28  

  HYPERLINK \l "_Toc56334371"  4.4	Build Institutional Memory and
Expertise	  PAGEREF _Toc56334371 \h  30  

  HYPERLINK \l "_Toc56334372"  4.5	Conclusion	  PAGEREF _Toc56334372 \h 
31  

  HYPERLINK \l "_Toc56334373"  5	Resources / References	  PAGEREF
_Toc56334373 \h  32  

  HYPERLINK \l "_Toc56334374"  Appendix A: Interview Guide	  PAGEREF
_Toc56334374 \h  34  

  HYPERLINK \l "_Toc56334375"  Appendix B: Contact Information	  PAGEREF
_Toc56334375 \h  36  

 

Introduction

Background 

The Clean Air Act (CAA) of 1990 requires that transportation plans,
programs and projects not cause or contribute to violations of the
health based air quality standards.  This requirement is met through the
transportation conformity process, which helps ensure that
transportation activities are consistent with, or are in
“conformity,” with regional air quality plans in air quality
nonattainment and maintenance areas.  

	

Although air quality is often thought of as primarily a concern for
urban areas, a number of rural locations are designated as nonattainment
or maintenance areas. Furthermore, EPA has promulgated a new eight-hour
ozone standard and fine particulate matter (PM-2.5) standard that are
expected to result in additional rural areas being designated as
nonattainment areas. These rural areas will be subject to the conformity
process for the first time, and thus will need to understand the
technical and procedural requirements.

The conformity process is critically important to transportation
agencies because a conformity determination must be made before
advancing Federally funded or approved transportation projects.  The
conformity process is complex, however, and many state and local
transportation agencies in rural areas have limited experience on
conformity requirements and how to meet them.  

A rural area is defined as an area with an urbanized population of less
than 50,000. Federal metropolitan transportation planning requirements
do not apply to these areas. This study focuses on isolated
nonattainment and maintenance rural areas (isolated rural areas), which
are rural areas not located within a metropolitan nonattainment or
maintenance area. These areas are different from so-called “donut”
areas, which are areas located inside a metropolitan nonattainment or
maintenance area boundary but outside the metropolitan planning boundary
(i.e., outside a Metropolitan Planning Organization’s boundary).
Isolated rural areas face different conformity requirements from
metropolitan areas and typically have limited access to resources and
technical tools.  

Study Purpose

The purpose of this report is to provide practical information to help
transportation staff better understand the conformity requirements in
isolated rural areas and the actions that need to be taken to meet them.


The objectives are threefold:

Describe the conformity requirements for isolated rural areas, and how
these differ from requirements in metropolitan areas and “donut”
areas;

Describe the experience of isolated rural areas with the conformity
process, including challenges faced, based on a limited set of
interviews with transportation and air quality staff in these regions;
and 

Highlight state of the practice and lessons learned from these
experiences.

Research Approach 

This study builds on a number of previous efforts to address air quality
issues in rural areas and the conformity process in general. The
research approach involved, first, a review of relevant documents, case
studies, and guidance on the conformity process, particularly as it
relates to isolated rural areas. This information was used to develop a
background guide on the conformity process focused on isolated rural
areas.

The research team then conducted a series of interviews with
transportation and environmental agency staff in seven states containing
isolated rural areas. The interviews were designed to collect
information both on existing experience with conformity in isolated
rural areas and actions being undertaken to prepare for conformity in
anticipated new isolated rural nonattainment areas under the eight-hour
ozone or fine particulate matter standards. 

The following seven states were selected for this study:

Colorado

Kentucky

Maine

Oregon

Ohio

Pennsylvania

South Carolina.

These states were selected using the following criteria:

Each state contains one or more existing isolated rural nonattainment or
maintenance areas for ozone, carbon monoxide, or particulate matter;
some areas also anticipate new isolated rural nonattainment areas under
the eight-hour ozone and/or PM-2.5 standards.

Each of the states has conducted at least one conformity analysis within
the past five years or is undertaking substantial efforts to prepare for
new rural nonattainment areas; this was an important criteria since many
isolated rural areas have not undertaken a conformity analysis in recent
years, according to a recent survey by FHWA. 

The states represent a geographic diversity in terms of regions of the
U.S., including all four AASHTO regions and six different EPA regions.

The research team began the interview process with state department of
transportation (DOT) staff because state DOTs typically take the lead in
conformity for isolated rural areas. State DOT staff also could describe
experience with more than one isolated rural area. Following the state
DOT interviews, the research team interviewed staff from the state air
quality agency in each of the selected states. In some cases, the
research team also interviewed staff from a regional EPA or FHWA
division office to supplement the interviews. 

Report Organization

This report contains the following sections:

Section 1: Introduction

This section describes the motivation and purpose of this report, as
well as the study approach.

Section 2: A Guide to Conformity Requirements for Isolated Rural Areas

This section defines what is meant by an isolated rural area, and
includes a summary of the conformity requirements for isolated rural
areas and how they differ from requirements of metropolitan areas. It is
intended to provide a simple description of what state and local
transportation practitioners in isolated rural areas need to know about
conformity requirements. 

Section 3: State of the Practice 

This section highlights findings from interviews conducted in seven
states, in terms of their experience with conformity in isolated rural
areas, practices used, and activities to prepare for potential new
nonattainment areas. These findings should help to inform existing and
new isolated rural areas about what to expect with the conformity
process. 

Section 4: Lessons Learned

This section summarizes key lessons to be taken from the experience of
the seven states. It highlights practices that were characterized as
particularly successful and provides recommendations.  

Section 5: Resources and References

This section provides information on resources that transportation staff
should be aware of to help prepare for conformity evaluations in
isolated rural areas. 

An Overview of Transportation Conformity Requirements and Isolated
Rural Areas  

Regulations governing transportation conformity are found in Title 40 of
the Code of Federal Regulations (40 CFR Parts 51 and 93). The specific
requirements for isolated rural areas are described in 40 CFR
§93.109(g). Given the unique issues associated with isolated rural
areas, the different requirements for these areas compared to
metropolitan areas, and the complexity of federal regulations,
transportation practitioners who are new to the conformity arena may
need assistance to decipher the requirements in these areas. Many states
have a small number of isolated rural non-attainment and maintenance
areas, and thus, have not had to conduct conformity analyses in isolated
rural areas often, or on a regular cycle.

This section is intended to help transportation and other agencies
understand the conformity requirements for isolated rural areas. It is
designed to provide a simple and concise summary of the key
requirements. It defines isolated rural areas and describes how the
conformity process differs between isolated rural areas, metropolitan
areas, and “donut” areas. This section draws from federal guidance
on the conformity process, including Transportation Conformity: A Basic
Guide for State and Local Officials and the Transportation Conformity
Reference Guide. Readers are urged to consult these resources, and other
references listed in Section 5 for more detailed information. 

Types of Rural Areas 

The U.S. DOT (FHWA/FTA) defines a rural area as an area having an
urbanized population of less than 50,000.  U.S. DOT’s metropolitan
planning requirements including those related to the development of
transportation plans and Transportation Improvement Programs (TIPs), do
not apply in these areas.

For conformity purposes, nonattainment and maintenance areas that are
rural fit into one of two categories: 

An isolated rural area is a rural area that is not located within or
adjacent to a metropolitan nonattainment or maintenance area; 

A “donut” area is a rural area that is located inside a metropolitan
nonattainment or maintenance area boundary, but is outside the
metropolitan transportation planning boundary. 

Exhibit 1 provides a visual diagram of the geographic differences
between these two types of areas. 

Exhibit 1: Difference between Isolated Rural Area and Donut Area

Although both types of rural areas may be similar in character, isolated
rural areas and donut areas are very different when it comes to
conformity analysis. An isolated rural area is not part of the emissions
analysis or transportation demand modeling analysis of any Metropolitan
Planning Organization’s (MPO) transportation plan or TIP. On the other
hand, donut area projects must be incorporated into the metropolitan
area’s regional emissions analyses and generally must follow the more
standardized metropolitan area process.

What Is Transportation Conformity?

Transportation conformity is a way to ensure that transportation plans,
programs, and projects that receive Federal funding and approval are
consistent with Federal air quality goals. It ensures that these
transportation activities do not worsen air quality or interfere with
the “purpose” of the State Implementation Plan (SIP), which is to
meet the national ambient air quality standards (NAAQS) set by the U.S.
Environmental Protection Agency (EPA). Meeting these standards often
requires emission reductions from on-road mobile sources.

According to the Clean Air Act (CAA), transportation plans, programs,
and projects cannot:

Cause new violations of the Federal air quality standards; 

Increase the frequency or severity of existing violations of the
standards; or 

Delay timely attainment of the standards. 

The CAA requires that transportation plans, programs, and projects in
nonattainment or maintenance areas that are funded or approved by the
Federal Highway Administration (FHWA) or Federal Transit Agency (FTA) be
in conformity with the SIP through the process described in the
transportation conformity regulation.  This requirement also applies to
projects that are not federally funded if they have regional
significance.

The foundation upon which a transportation conformity determination is
based is the motor vehicle emissions budget contained in an approved SIP
or a SIP budget that has been found adequate by EPA. It is this budget
which establishes the ceiling on aggregate emissions allowed from
transportation sources. The regional emissions analysis is the major
analytical element of the conformity process. A regional emissions
analysis must show that the emissions resulting from the planned
transportation system will not exceed the budget for specific analysis
years. 

In areas where budgets are not required, emission reduction tests are
used. There are two such tests: 

“Less than baseline” test - shows that emissions are less than the
baseline year emissions.

“Build/no build” test - shows that emissions from implementing the
plan (the action/build scenario) are less than if the plan were not
implemented (the baseline/no build scenario).  

Transportation Planning and Conformity Requirements in Metropolitan
Areas

Under U.S. DOT’s planning regulations, Metropolitan Planning
Organizations (MPOs) must have transportation plans in place that
present a 20-year perspective on transportation investments for their
region. The MPO must also have a transportation improvement program
(TIP), which is a multi-year prioritized list of projects (covering at
least 3 years) including all projects that require funding or approval
by FHWA or FTA.  The transportation plan must be updated every three
years in nonattainment and maintenance areas and the TIP every two
years. The Clean Air Act section 176(c) and conformity rule requires
conformity to be demonstrated not less frequently than every three
years.  

In general, the conformity process involves three components:

Plan Conformity - The transportation plan must be shown to conform to
the SIP, based on a regional emissions analysis for the plan;

TIP Conformity – The TIP must be shown to be consistent with the
transportation plan and SIP before it can be approved, based on a
regional emissions analysis; and

Project Conformity - FHWA/FTA projects must be found to conform before
they are adopted, accepted, approved, or funded. This means that
transportation projects must conform to the following criteria: 1) they
must come from a conforming transportation plan and TIP; 2) the design
concept and scope of the project that was in place at the time of the
conformity finding must be maintained through implementation; and 3) the
project design concept and scope must be sufficiently defined to
determine emissions at the time of the conformity determination. 

Regions that are designated as carbon monoxide (CO) or particulate
matter (PM-10) nonattainment or maintenance areas must also show that
new localized violations of those pollutants will not result from
project implementation. Certain types of projects are exempt from
conformity requirements (e.g. safety, landscaping, and other projects
with neutral or minimal emissions impacts).

While conformity determination is required at least every three years,
certain events, such as SIP revisions that establish or revise a
transportation-related emissions budget, or add or delete transportation
control measures (TCMs) also trigger new conformity determinations. 
Conformity analyses must also be conducted for each new project unless
it is an exempt project.

Within the conformity process, the regional emissions analysis should
reflect emissions of all travel, including all FHWA/FTA projects.
Modeling must also include all regionally significant projects,
regardless of project funding source. Projects that are not regionally
significant are not required to be modeled, but vehicle miles traveled
(VMT) from such projects must be estimated in accordance with reasonable
professional practice. Certain types of projects are exempt from
conformity, such as safety projects, maintenance activities,
rehabilitation of transit vehicles, and bicycle and pedestrian
facilities, as long as they do not have potential adverse impacts on
emissions. 

The regional emissions analysis must estimate total projected emissions
for a number of different future years. Per §93.118(d)(2) of the
transportation conformity rule, analysis years must include:

Any years in the time frame of the transportation plan, provided they
are no more than 10-years apart;

The attainment year (if it is within the time frame of the
transportation plan); and

The last year of the transportation plan (at least 20 years in the
future).

Conformity Requirements for Donut Areas

A donut area is a geographic area that falls within the boundary of a
nonattainment or maintenance area that contains a metropolitan area, but
falls outside of the metropolitan planning area boundary. Emissions in
donut areas must be included in the metropolitan area regional emissions
analysis for the Plan and TIP. As a result, in most cases transportation
emissions in donut areas must be analyzed and documented on the same
schedule as the conformity analysis for the MPO area. In some cases, the
State DOT takes the lead in analyzing emissions in donut areas, in
coordination with the MPO. The process for addressing the donut areas is
subject to agreement through the interagency consultation process.  

Conformity Requirements for Isolated Rural Areas

An isolated rural nonattainment or maintenance area does not contain and
is not part of any metropolitan planning area.  Isolated rural areas do
not have metropolitan transportation plans or TIPs and do not have
projects that are part of the emissions analysis of any MPO’s
metropolitan transportation plan or TIP.  Projects in such areas are
instead included only in statewide transportation improvement programs
and in some cases in the statewide transportation plan.

As in other areas, the conformity process is intended to ensure that
transportation projects conform to the SIP.   However, isolated rural
areas do not have a federally required metropolitan transportation plans
or TIPs.  As a result, the conformity frequency requirements for plans
and TIPs (including the three-year conformity update requirement) do not
apply.  

Federal transportation projects in isolated rural areas must be
consistent with the Statewide Transportation Plan and incorporated into
the Statewide Transportation Improvement Program (STIP) prior to any
federal approval. A regional conformity analysis must be conducted,
therefore, only when a project sponsor seeks FHWA or FTA approval or
funding for a regionally significant, non-exempt project, or if there is
a change in the design concept or scope of a regionally significant
project that was in place at the time of the conformity finding. In
addition, conformity must be redetermined for any FHWA/FTA project if
three years have elapsed since the most recent major step to advance the
project occurred.  Major steps are defined as the following: NEPA
process completion; start of final design; acquisition of a significant
portion of the right-of-way; or approval of the plans, specifications
and estimates.

Overview of Isolated Rural Area Requirements /Differences from
Metropolitan Areas

In general, the conformity requirements for isolated rural areas are
similar to metropolitan nonattainment or maintenance areas except that:

frequency requirements for updating conformity in metropolitan areas do
not apply, and

some flexibility is available to isolated areas for the years after the
attainment date or the last year of the maintenance plan.

The state DOT often plays a key role in determining conformity in
isolated rural areas.  This is because isolated rural areas ordinarily
do not have transportation planning agencies or regional modeling
capabilities. The state DOT usually performs the analytical work
necessary to make a conformity determination in such areas, in
conjunction with the state environmental agency and local or county
transportation agencies. 

Exhibit 2 contains a flowchart that shows the general process and
conformity requirements for isolated rural areas. The steps in this
process are described below.

Exhibit 2: Conformity Process in Isolated Rural Areas

Regional Emissions Analysis

A regional emissions analysis is required that includes travel from the
entire transportation system, including all Federal projects, and all
regionally significant non-Federal projects in the isolated rural
nonattainment or maintenance area. If there is no new regionally
significant non-exempt project requiring Federal approval, no conformity
analysis is required for that area. 

Projects in isolated rural areas must be included in a statewide
transportation improvement program (STIP) prior to any Federal action to
fund the project. Any Federally funded project must also meet National
Environmental Policy Act (NEPA) requirements.

The required regional emissions analysis tests for isolated rural areas
depend on whether the area has an emissions budget or not. If an area
has an approved budget or an emissions budget found adequate by EPA, the
emissions budget test must be used. If the area does not have an
adequate emissions budget, emission reduction tests are used; the
specific test that must be used depends on the area’s classification.
In addition, for the period after the attainment date or the end of the
attainment or maintenance period, isolated rural areas have flexibility
in the regional emissions analysis tests for those “out-years”
whereas other areas do not have this flexibility. The requirements are
shown below in Exhibit 3. 

Exhibit 3: Regional Emissions Analysis Tests Required for Isolated Rural
Areas

Type of Area	Analysis for years during time frame 

of last adequate SIP	

Analysis for years after time frame of last adequate SIP

	

No Emissions Budget	

Adequate Emissions Budget

	The following areas, which are required to submit a control strategy
SIP containing an emissions budget: 

Moderate or above ozone areas 

Moderate CO areas with design value greater than 12.7 ppm 

Serious CO areas	

If no adequate or approved budget is submitted, a regional emissions
analysis must be performed that meets the following emissions reduction
tests: 

build/no-build and less-than 1990	

Conduct regional emissions analysis meeting emissions budget test (as
long as the budget has been found adequate or approved by EPA). 

	

Projects must satisfy one of the following: 

1) Regional emissions analysis meeting emissions budget test;

2) Build/no-build and less than 1990 test including NOx in ozone areas,
or

3) Air quality model as used in last adequate or approved SIP



Rural PM10 areas (which are required to submit a control strategy SIP
containing an emissions budget)

Any rural NOx area.	If there is noadequate or approved budget, a
regional emissions analysis must be performed that meets the 

build/no-build or no-greater-than-1990 tests

Projects must satisfy one of the following: 

1) Regional emissions analysis meeting emissions budget test;

2) Build/no-build or no-greater-than 1990 test including NOx in ozone
areas, or

3) air quality model as used in last adequate or approved SIP



Areas not required to submit a control strategy SIP containing an
emissions budget:

Rural transport ozone area

Marginal and below ozone area

Incomplete data ozone area

Moderate CO area with design value of 12.7 ppm or less

Unclassified CO area



	Source: Based on Exhibit 37 of the Federal Highway Administration
Transportation Conformity Reference Guide. Revised July 31, 2001. 

	

Regional Emissions Analysis Tests for Periods Before Attainment Date or
End of Maintenance Period

For analysis years before the attainment date or end of the maintenance
period, the tests that must be applied depend on the classification of
the area and whether it has an adequate emissions budget.

Tests for Areas Required to Submit SIPs

Areas that are required to submit control strategy SIPs are:  moderate
and above ozone areas; CO areas classified as serious or as moderate
with a design value of greater than 12.7 ppm; and PM-10 areas. In
addition, other areas can choose to voluntarily submit a motor vehicle
emissions budget.

As shown in Exhibit 3 above, isolated rural areas that have SIPs in
place with adequate or approved motor vehicle emissions budgets must
meet the budget test for the period of the SIP or maintenance plan. This
means that emissions from on-road mobile sources cannot exceed the
budget for specific analysis years including the attainment year or, in
a maintenance area, the last year of the maintenance plan. If there is
no adequate or approved emissions budget, the regional emissions
analysis must use both the build/no-build and the less-than-1990 tests,
with the exception of PM-10 areas, which may use either the build/no
build or the no-greater-than-1990 test. 

Tests for Areas Not Required to Submit SIPs 

Areas that are not required to submit control strategy SIPs include the
following:

Rural transport ozone nonattainment areas,

Marginal ozone areas,

Submarginal ozone areas,

Incomplete data ozone areas,

Moderate CO areas with a design value of 12.7 ppm or less, and

Not classified CO areas.

In order to demonstrate conformity, projects located in one of the above
areas that is an isolated rural nonattainment or maintenance area must
meet one of the emission reduction tests in 40 CFR 93.119 for all
applicable pollutants or pollutant precursors (including NOx in ozone
areas) within the nonattainment area.  

The emissions reduction test that is applied can be either the
build/no-build test or the no-greater-than-1990 emissions level test.
The emissions budget test is not applied in the above areas unless the
State voluntarily submits an attainment demonstration and accompanying
motor vehicle emissions budget(s) or maintenance plan. In such a case,
the budget test replaces the above emissions reduction test once the EPA
finds the budget adequate for conformity purposes. 

Regional Emissions Analysis Tests Beyond the Attainment Year or Last
Year of Maintenance Plan

For the years beyond the attainment year or last year of the maintenance
plan, an isolated rural area can choose among three tests:

 

Budget test - The area can use the budget test to demonstrate that
on-road mobile source emissions, including those from all regionally
significant projects, will not exceed the motor vehicle emissions budget
for the attainment year or the end year of the maintenance plan, 

Emission reduction test(s) - The area can use the emissions reduction
tests that apply to that classification of nonattainment area to
demonstrate conformity for the years beyond the attainment date or end
year of the maintenance plan. As shown in Exhibit 3: 

For moderate or above ozone areas, moderate CO areas with design value
greater than 12.7 ppm, and serious CO areas, both the build/no-build and
the less-than-1990 tests are required; 

For other areas, either the build/no-build or no-greater-than-1990 test
is required, or,

Air quality modeling - The area can demonstrate through air quality
modeling used in the attainment SIP or maintenance plan that the project
in combination with all other regionally significant projects expected
in the area in the time frame of the statewide transportation plan, will
not:

Cause or contribute to any new violation of any standard in any areas; 

Increase the frequency or severity of any existing violation of any
standard in any area; or,

Delay timely attainment of any standard or any required interim
emissions reductions or other milestones in any area. 

In choosing which option to use for regional emissions analysis beyond
the attainment date or end date of the maintenance plan, the state DOT
must use the interagency consultation process established in accordance
with the conformity rule. 

Exhibit 4 provides an example of how an isolated rural area may conduct
a regional emissions analysis using different tests for different
analysis years.

Exhibit 4: Example of Regional Emissions Analysis – Ozone Maintenance
Area

Regional Analysis Without a Travel Demand Model

If there is no network-based travel demand model in the isolated rural
area, estimates of vehicle miles traveled (VMT) based on FHWA’s
Highway Performance Monitoring System (HPMS) or locally-approved traffic
counts will need to be developed for vehicle travel in the area.  These
data can then be used to generate regional emissions estimates for each
analysis year, which in turn will be used to perform the required motor
vehicle emissions budget or emissions reduction tests.

Project Level (Hot Spot) Emissions Analysis

Project level analysis is required in CO and PM-10 nonattainment and
maintenance areas.

In rural CO nonattainment or maintenance areas, projects that require
Federal approval or funding must also meet the CO hot spot tests as
required under the conformity rule (40 CFR 93.116 and 93.123). In CO
nonattainment areas, it must be shown that the project will improve air
quality and in CO maintenance areas, it must be shown that the project
will not create new violations. For CO nonattainment areas, quantitative
analysis is required for certain projects such as those that are listed
in the SIP as having the worst level of service (LOS) in the
nonattainment area.  For all other projects, a qualitative analysis is
required.

For PM-10 nonattainment areas, qualitative analysis is required to
ensure that new PM-10 hotspots are not created and that projects will
not delay progress toward attainment; in PM-10 maintenance areas,
qualitative analysis is required to show that the project will not
create new violations. The projects to be analyzed and analysis tools to
be used are subject to agreement through the interagency consultation
process.

General Requirements

As with metropolitan areas, some general requirements apply for all
conformity analyses. Some of the key requirements are highlighted below.

Latest Planning Assumptions

As part of the regional emissions analysis, the latest planning
assumptions requirements apply.  This means that the latest demographic
information (e.g., population, employment, land use) and travel
information (e.g., vehicle classification, age and turnover of fleet,
vehicle miles traveled) must be used in the regional emissions analysis.

Latest Emissions Model

The latest EPA-approved emissions model must be used in estimating
emissions in isolated rural nonattainment and maintenance areas.  In
isolated rural areas, the model is ordinarily run by either the state
DOT or the state environmental agency because isolated rural areas
rarely have the resources to conduct emissions analysis. 

Interagency Consultation

The interagency consultation process that applies to metropolitan areas
also applies to isolated rural areas. The state DOT or rural area agency
should initiate the process and ensure that key assumptions are agreed
to.  In isolated rural areas, the lead is likely to be taken by the
state DOT but interagency consultation also includes the state
environmental agency, local public works departments, local transit
agencies, and other local agencies as appropriate.

Timely Implementation of TCMs 

In all cases, projects that are not from a plan or TIP (such as those
projects implemented in isolated rural areas) must not interfere with
the implementation of any transportation control measures in a State
Implementation Plan (SIP). 

State of the Practice

This section summarizes experiences with transportation conformity in
isolated rural areas, drawn from interviews with the following seven
states:  Colorado, Kentucky, Maine, Oregon, Ohio, Pennsylvania, and
South Carolina. Given the small sample of states, the results cannot
necessarily be extrapolated to the nation as a whole. However, the
findings do provide an indication of the ways in which conformity
analysis has been undertaken in isolated rural areas, the types of
issues encountered, and the perceived ramifications for transportation
and air quality. This section also reports on what types of actions
states are taking to prepare for new nonattainment areas that will be
designated under the eight-hour ozone and fine particulate matter
standards. This information, in turn, is designed to help practitioners
better understand the current state of the practice in isolated rural
areas and actions that can be taken to prepare areas for conducting
transportation conformity analyses.

The key lessons learned from these experiences and recommendations are
summarized in Section 4 of this report.

This section is divided into the five sub-sections, which address the
following questions:  

Frequency of Conformity Analysis

How often were conformity analyses conducted?

Role of State DOT and Local Agencies

Who was involved?

Outcomes 

How many areas had a problem meeting conformity?

What types of effects has conformity had on transportation decisions?

Issues Encountered in the Conformity Process

What types of issues or challenges arose, and how were these resolved?

How has interagency consultation worked?

What data and tools were used for emissions analysis?

Preparation for New Standards

How are the new eight-hour ozone and fine particulate matter standards
expected to affect the number of isolated rural areas subject to
transportation conformity? 

And what is being done to prepare for the new standards?

Frequency of Conformity Analysis 

Isolated rural areas are required to conduct conformity analyses only
when there is a new non-exempt project or if there are significant
changes to the scope or timing of a non-exempt project. Many of the
areas interviewed for this research stated that there have been few
projects in isolated rural areas, and consequently few conformity
analyses have been conducted. 

Exhibit 5 summarizes the isolated rural areas and conformity analyses
that have been conducted for the seven states interviewed for this
study. 

Exhibit 5: Conformity Analyses Conducted 

State	Number, Location, and Current Designation of Isolated Rural Areas:
Conformity Analyses Conducted

Colorado 	Six (6) areas:

Aspen - PM-10 maintenance 

Canon City – PM-10 maintenance 

Lamar – PM-10 maintenance

Pagosa Springs – PM-10 maintenance 

Steamboat Springs – PM-10 maintenance

Telluride – PM-10 maintenance 	Only one conformity analysis has ever
been conducted - Entrance to Aspen project on State Highway 82
(1995/96).

Kentucky	Two (2) areas:

Paducah (Marshall Co. and Part of Livingston Co.)– ozone maintenance

Edmonson County – ozone maintenance

	Conformity analyses have been conducted in both of the isolated rural
areas in the state within the past five years: Edmonson in 1999; Paducah
failed to determine conformity in 1998, but eventually was able to make
a conformity determination in 2002 after revising its motor vehicle
emissions budget in the SIP. 

Maine	Three (3) areas:

Hancock and Waldo Co. – ozone maintenance

Knox and Lincoln Co. – moderate for ozone 

Presque Isle – PM-10 maintenance (exempt from regional emissions
analysis requirements because mobile sources are insignificant)

	No significant projects requiring a conformity determination have been
initiated within past five years but rural conformity analyses are
conducted on a routine basis as part of the STIP cycle. 



Ohio	Four (4) areas:

Clinton Co. –ozone maintenance

Columbiana Co. –ozone maintenance

Jefferson Co. – PM-10 maintenance (exempt from regional emissions
analysis requirements because mobile sources are insignificant)

Preble Co. – ozone maintenance	Conformity analyses have been conducted
in Clinton (about 1999/2000) and Columbiana (not within past five
years).   

Oregon	Five (5) areas:

LeGrande (Union Co.) – moderate PM-10 

Lakeview (Lake Co.) – moderate for PM-10

Oakridge (Lane Co.) – moderate for PM-10 (exempt from regional
emissions analysis requirements because mobile sources are
insignificant)

Klamath Falls (Klamath Co.) – maintenance for CO, moderate for PM-10
(EPA redesignation and maintenance plan approval pending)

Grants Pass (Josephine Co.) – maintenance for CO, moderate for PM-10
(EPA redesignation and maintenance plan approval pending) 

	Conformity analyses have been conducted in Lakeview, Klamath Falls, and
Grants Pass.  

Pennsyl-vania	Eleven (11) areas:

Crawford Co. – ozone incomplete data 

Franklin Co. – ozone incomplete data 

Juniata Co. – ozone incomplete data 

Lawrence Co – ozone incomplete data 

Northumberland Co. – ozone incomplete data 

Pike Co. - ozone incomplete data 

Schuylkill Co. – ozone incomplete 

Snyder Co. – ozone incomplete data 

Susquehanna Co – ozone incomplete data

Warren Co. – ozone incomplete data 

Wayne Co. – ozone incomplete data 

	Rural conformity analyses are conducted on a routine basis as part of
the STIP cycle. In generally, isolated rural areas each had between two
and five projects over of the past 4 years.

South Carolina	One (1) area:

Cherokee Co.– ozone maintenance	One conformity determination has been
made.  Regional conformity analysis included four projects in Cherokee
County, generally associated with widening I-85 and approach routes.



As shown in the table above, the states we interviewed each contain from
one to six isolated rural non-attainment areas, with the exception of
Pennsylvania, which has eleven ozone areas, classified as incomplete
data areas. Most states have had only a handful of regionally
significant non-exempt projects requiring conformity determinations. For
example, within the six isolated rural PM-10 areas in Colorado, only one
conformity analysis has ever been conducted. Within the four isolated
rural areas (three for ozone, one for PM-10) in Ohio, only one
conformity analysis has been conducted within the past five years.  In
Oregon, conformity analyses have been conducted in three of five
isolated rural areas. PennDOT staff estimated that there were an average
of two to five non-exempt projects in each area over the past four
years.  This somewhat higher frequency of non-exempt projects may be due
to the fact that each of Pennsylvania’s isolated rural maintenance and
non-attainment areas encompasses an entire county, while other states
isolated rural areas tend to be smaller.

Two of the sample states – Pennsylvania and Maine – conduct
conformity analyses for areas on a routine basis as part of their STIP
cycle, despite the fact that conformity analyses in isolated rural areas
are only required when there are regionally significant non-exempt
projects. In the case of Pennsylvania, the state DOT indicated that even
where no new significant projects have been added, other changes might
cause emissions calculations to change (e.g., fleet mix, registration
data, etc.).  The state DOT chooses to conduct conformity analyses to
incorporate such new data even when no new projects are planned for a
given area; however, the conformity regulation does not require a new
analysis and determination in these cases.  In the case of Maine, the
state DOT staff indicated that they believed analyses were required at
least every three years, and so went through the process of conducting
an analysis regularly.  

Some states such as Oregon and Pennsylvania expect even fewer rural
conformity determinations in the future.  This is partly because these
states expect to continue current trends that have shifted funds toward
system preservation and safety enhancement activities and away from
activities involving new infrastructure development and capacity
expansion.  This shift may be most significant in slower growth states,
but in some cases it represents a more general shift in investment
priorities.  More immediately, over the next several years many states
foresee budget shortfalls that may preclude regionally significant
transportation projects in rural areas.  

Role of State DOT and Local Agencies

Within all the states we interviewed, the State DOT played the lead role
in conducting conformity analyses for isolated rural areas. In some
cases, local agencies did not play any substantive role in the
conformity process. In none of the cases did local agencies conduct the
technical work for the regional emissions analysis. They also typically
did not participate in interagency consultation activities, and in some
cases probably had no idea that conformity analyses were being
conducted, according to state DOT staff.  

Of the seven states, Colorado, Oregon, and Pennsylvania indicated that
local governments played a role in the conformity process. The level of
involvement and role in the process differed:

In Colorado, the local governments in the City of Aspen / Pitkin County
worked with Colorado DOT and the Colorado Air Pollution Control Division
to provide input on control measures as part of a conformity analysis in
the Aspen area. While the state agencies work with local agencies
throughout the Colorado, the Aspen area is known for a high level of
local involvement, and works more closely with CDOT than most rural
communities in the state. It is also somewhat unique in terms of air
pollution controls, since paid parking in Aspen is a legally enforceable
control measure in the SIP. 

Oregon had a relatively high degree of local involvement in Grants Pass,
Lakeview, and Klamath Falls.  In Oregon, a number of local and regional
air pollution organizations had been formed to deal with air quality
concerns. Oregon DOT involved these organizations in the conformity
process. Since local residents trusted these organizations, these groups
turned out to be a valuable means of communicating with public
constituencies.

Pennsylvania involves Local Development Districts (LDDs) in the
conformity meetings at the early stages to discuss schedules and ensure
that all regionally significant projects have been identified.  Once the
data and report are assembled, they are sent to the LDD approval body. 
The approved report comes back to PennDOT, which assembles all the
pieces for the statewide conformity document.  Each LDD has a technical
committee and an approval body that endorses the report.

There are a number of reasons why state DOT staff members play the key
role in conformity for rural areas. Most state DOT staff indicated that
local transportation agencies and governments have limited understanding
of the conformity requirements and lack the technical expertise to
undertake such analysis. Moreover, most projects in isolated rural areas
are state highway projects; as such, the state DOT includes the projects
in the STIP and conducts environmental assessments. Moreover, the state
DOT is in a better position to handle interagency consultation involving
the state air agency, FHWA, FTA, and EPA. 

Many state DOTs felt that local officials typically only take an
interest in conformity at the point where a desired project is
threatened.  In two specific cases where local agencies and officials
actually were involved, it occurred as a result of project delays. In
Oregon’s Grants Pass area, local officials became involved because
problems meeting conformity caused delay for a downtown street
improvement project.  In Paducah, Kentucky, local officials involved
themselves once they learned that a highway project was stopped because
of challenges in satisfying conformity requirements.

Outcomes 

Meeting Conformity: Problems Encountered and Solutions 

The seven states interviewed had a wide range of experience in terms of
ease of meeting conformity requirements. Many of the states interviewed
expressed that they had not encountered any significant problems in
meeting the emissions budget or emissions reduction tests in isolated
rural areas. However, there have been a number of cases where a state
was not able to initially demonstrate conformity for a project, causing
project delays. Moreover, there were procedural difficulties, stemming
from limited experience with conformity, which hindered the ease of
demonstrating conformity in some cases. 

Exhibit 6 provides a summary of outcomes of conformity analyses that
have been conducted.

Exhibit 6: Outcomes of Conformity Analyses

State	Conformity Analyses Conducted	Outcomes

Colorado 	Aspen - Entrance to Aspen project on State Highway 82.  
Initial project was not able to meet build-no build test. Conformity
process influenced design of project: added busway/light-rail component.
[However, project is on hold due to other issues].

Kentucky	Edmonson 

Paducah 	Paducah – failed to determine conformity in 1998. Eventually
was able to make a conformity determination in 2002 after revising its
motor vehicle emissions budget in the SIP.

Maine	Rural conformity analyses are conducted on a routine basis as part
of the STIP cycle. 

	No significant projects. Problem has been identifying projects to
conduct build/no build test.

Ohio	Clinton 

Columbiana   	No problems meeting conformity have been encountered.

Oregon	Lakeview

Klamath Falls

Grants Pass	Grants Pass – Experienced difficulty in demonstrating
conformity; however, the project was delayed long enough that fleet
turnover, as reflected in an upgraded MOBILE model, allowed the area to
demonstrate conformity.

Pennsyl-vania	Conformity analyses are conducted for the eleven isolated
rural counties during each two-year STIP cycle. There have been two to
five projects in isolated rural areas in over the past two STIP cycles. 
	No projects have been delayed, but project components have been
modified in order to demonstrate conformity. Conformity demonstration
was challenging with the build/no-build test but there have been no
problems meeting conformity using the “less than 1990” test.  

South Carolina	Cherokee County	Conformity analysis for project was
initiated in 1995 but only completed in 2000, due to a variety of
technical and procedural issues, not issues associated with meeting the
emissions budget. 



To a large degree, state DOT staff indicated that federal or state
actions have been successful in reducing emissions. These actions have
enabled areas to demonstrate conformity, particularly in terms of
meeting the “less than 1990” test. For example, in Pennsylvania,
where isolated rural areas do not have an emissions budget (as ozone
incomplete data areas), the state has been able to show conformity using
the “less than 1990” test. In the future, new federal requirements
are expected to help many isolated rural areas reduce emissions further.


In states in the sample with emissions budgets, there were generally few
problems meeting the emissions budget limits. For example, Ohio and
South Carolina indicated that they have never had problems staying
within their emissions budgets. 

Only one state in the sample – Kentucky - indicated that it had faced
a problem meeting conformity that was severe enough to require a
revision to the SIP emissions budget. In Paducah, Kentucky, a project on
U.S. Route 68 was included in the STIP, but was not able to meet the
emissions budget test. The emissions budget for the isolated rural area
did not allow for travel growth over time, and the Kentucky
Transportation Cabinet (KYTC) could identify no feasible means to meet
the test, despite several attempts, including developing vehicle speeds
for roadway classifications and investigating whether the hot and cold
start fractions were appropriate. KYTC made the case to the Kentucky
Division for Air Quality (DAQ) that revising the SIP motor vehicle
emissions budget was necessary because the inventory on which the budget
was developed was outdated and had underestimated future growth. The
process of convincing the DAQ of the need for a SIP revision was
difficult, as the DAQ was hesitant to undergo the potentially complex
process involving reexamination of emissions contributions from all
sources. Ultimately, the SIP was revised to increase the emissions
budget. However, the affected segment of the project was delayed from
early 2000 until the resolution of the conformity issue in late spring
2002.

In two other cases, states initially had a problem meeting conformity
that caused project delay, but these were resolved without requiring a
revision of the SIP. In Oregon, a highway project in the Grants Pass
carbon monoxide nonattainment area was not able to meet conformity
initially, and the project was delayed as a result. However, the area
was later able to meet conformity without any project changes due in
part to vehicle fleet turnover, which resulted in lower emissions for
the current year. In addition, new modeling techniques that were
implemented in the transition from MOBILE4 to MOBILE5 lead to lower
emissions estimates and helped to meet conformity. In Colorado, the
Entrance to Aspen project on State Highway 82 did not meet conformity
with the initial project design. However, by adding a busway/light rail
component, the state was able to demonstrate conformity.

In addition to these challenges satisfying regional emissions analysis
tests, several states experienced problems meeting conformity due to
procedural issues. Many of these problems stemmed from lack of
familiarity with the conformity process in isolated rural areas, and the
“learning curve” involved in understanding conformity requirements.
For instance:  

In Maine, it appears that there have been misunderstandings in regard to
the frequency requirements for conformity analysis in isolated rural
areas. The DOT goes through the conformity process for all nonattainment
areas, including isolated rural areas, every two years when they update
the STIP. Because it has isolated rural areas that are moderate for
ozone, but with no emissions budget, these areas must meet BOTH the
less-than-1990 test AND the build/no-build test. Maine DOT staff
indicated that they have no problems meeting the less-than-1990 test,
but have had problems meeting the build/no-build test when there are no
projects in an isolated rural area. As a result, the DOT has tried to
identify projects for these isolated rural areas, even when no project
would otherwise have been planned, in order to pass the build/no build
test. It appears that this problem would not exist if conformity
analyses were only conducted when there are new non-exempt projects. 

In Pennsylvania, PennDOT had problems when it began conducting
conformity analyses using the build/no-build test in isolated rural
areas. The “less than 1990” test is easier to meet because Federal
and state emissions reduction measures that have reduced motor vehicle
emissions. After it was recognized that the isolated rural areas could
use either test, due to their status as ozone incomplete data areas
(without a budget), the state has used the “less than 1990” test,
and has experienced no problems meeting conformity in isolated rural
areas.

In South Carolina, it took about a five-year timeframe, 1995 to 2000, in
order to demonstrate conformity for a project to widen I-85 in Cherokee
County, largely due to limited information on conformity requirements
and procedural issues involving the state air agency. The DOT submitted
an EIS for the project in 1998, and was informed by the FHWA regional
office that a conformity analysis needed to be completed before the EIS
could be accepted. The conformity process was basically unknown by staff
at the state level – both within the state DOT and air agency.
Cherokee County is the only nonattainment/maintenance area in the state,
so a conformity analysis had never been previously conducted, and there
was a substantial learning curve in terms of addressing all of the
conformity requirements. First, the SIP had to be revised to incorporate
updated mobile emissions factors.  And the mobile source budget had to
be increased.  While staff succeeded in demonstrating that the isolated
rural area would be under the new emissions budget, the SIP still needed
to be updated since it had been developed initially using an earlier
version of the MOBILE model. There were also some issues associated with
different interpretations of the regulations by the EPA regional office
and FHWA, which caused delay. 

Issues Encountered in the Conformity Process 

Time and Resources Involved in Comparison to Effects on Air Quality 

Although state DOT staff recognized the intent of the conformity
process, a number of state DOTs expressed concern that the conformity
process in isolated rural areas can take significant time and resources,
without producing meaningful air quality benefits.

In many isolated rural ozone areas, transportation sources play a small
role in contributing to air quality problems. For example, in Paducah,
KY, and Cherokee County, SC much of the ozone problem was due to
transport from other areas. Some state DOT staff questioned whether
isolated rural areas had significantly different air quality from
surrounding areas.  In one case, the DOT staff felt that their
designation as a nonattainment area, which prompts conformity
requirements, had more to do with the presence of an air quality monitor
than anything else. In another case, the DOT explained that an area
reached attainment because of three consecutive years of good weather.

Moreover, the amount of time invested in rural conformity processes can
be very large relative to the small amount of mobile source emissions
associated with the project.  In the case of Paducah, the U.S. 68
project, which was delayed as a result of conformity problems, involved
a 15- to 17-mile section of highway, including a replacement bridge over
Kentucky Lake; only about 2,000 feet of the project was located within
the ozone maintenance area, but required considerable effort and
resources to address. As noted earlier, in Grants Pass, Oregon, a
project was delayed because it was not able to meet conformity
initially; however, the area was later able to demonstrate conformity
with exactly the same project because of vehicle fleet turnover and
changes in the methodology applied within the emissions models. After a
period of delay, the analysis found that the project no longer had a
meaningful effect on air quality. Due to these issues, a number of
agencies felt that rural conformity requirements should provide greater
flexibility to address situations where required staff time and
resources would be disproportionate to the air quality benefits possible
through mobile source reductions.

On the other hand, most state DOTs and air agencies felt that the
transportation conformity process was an important motivator to increase
interaction and coordination between the air agencies and the DOTs. 
Such interactions almost never took place before conformity was
required. In this regard, the process has been a success.  Pennsylvania
DOT, for example, noted that the rural conformity process has had an
effect on the mix of projects they select. There is now a greater focus
on projects that improve traffic safety in rural areas, and there is
less likelihood of new “megaprojects” that can seriously impact a
rural area’s ability to achieve conformity. Conformity has also
increased attention to signal coordination in rural areas as a
mitigation strategy. Within a number of states, DOT staff expressed that
air quality concerns are rarely a priority for public officials in rural
areas and it is challenging to persuade public officials to take these
concerns seriously at an early stage in the planning process. Therefore,
by raising the possibility of stopping projects, the conformity process
forces a serious consideration of these issues.

In some cases, experience with conformity in isolated rural areas has
also informed efforts to reduce emissions in other parts of the state.
For example, high PM-10 concentrations registered in Triple Creek,
Colorado threatened to bring this area into nonattainment. Based on
Colorado’s experience with nonattainment and maintenance areas,
Colorado DOT (CDOT) examined road-sanding practices, which had been
identified previously as a key problem in rural PM-10 nonattainment
areas.  A review of road sanding practices found that between CDOT and
local road crews, the roads were being significantly over-sanded.  As a
result, the state and local agencies coordinated to reduce sanding.
CDOT’s six engineering regions each have regional environmental
managers and maintenance superintendents that are now aware of potential
PM-10 problems and are cooperative in the effort to manage these
impacts. 

Feasibility of Reducing On-Road Emissions in Isolated Rural Areas 

Transportation agencies in some states expressed concern about the
feasibility of reducing emissions from motor vehicles in isolated rural
areas. Traditional TCMs to reduce the demand for vehicle travel have
limited application in most rural areas. Population densities are not
high enough to support transit, ridesharing, bicycling, or other demand
management measures. As a result, options available to state DOTs to
reduce emissions are severely constrained. In Paducah, Kentucky, for
example, state DOT staff felt that there were few viable opportunities
to reduce emissions of ozone precursors by an amount sufficient to meet
the emissions budget.

On the other hand, there were some cases in which isolated rural areas
had opportunities to reduce on-road emissions. For example Aspen,
Colorado was able to demonstrate reduced emissions by adding a transit
component. Although Aspen, Colorado has only about 6,000 residents, the
population expands dramatically when all the workers who live down
valley come into town and tourists add to traffic volumes. The plan to
widen State Route 82 into Aspen would not meet conformity solely as a
road widening project. However, the inclusion of a busway or light-rail
component reduced the predicted VMT and mitigated community concerns
about traffic. With the redesign, the project was able to meet
conformity. 

In the case of isolated rural PM-10 areas, road dust is often a major
source of emissions, and there are opportunities to reduce fugitive dust
from rural transportation including paving commonly used dirt roads and
switching from sand to chemical road de-icers. In Colorado and Oregon,
where much of the PM-10 problem was due to road dust, DOTs have
successfully reduced emissions using these strategies. These experiences
suggest that there are cases – such as in resort-type areas and PM-10
areas – where there are reasonable opportunities to reduce motor
vehicle emissions.

Role of Interagency Consultation 

The interagency consultation process is the formal coordinating
mechanism among transportation and air agency staffs.  Although some
states have experienced problems in the past, interview subjects
generally felt that their procedures for interagency consultation were
working effectively, and emphasized the importance of coordination.  In
many cases, states characterized their coordination with the air agency
as being very effective. Several practitioners, however, noted that
establishing an interagency consultation agreement takes significant
time, preparation, development of professional trust, and legal
expertise, and so significant time should be allotted for this aspect of
the process.  

The actual mechanism of the interagency consultation process, in terms
of number of meetings, appeared to vary considerably among states. Some
states found it valuable to hold regular meetings between the State DOT,
the State air agency, EPA, FHWA, and FTA while others felt that this
exchange worked best if meetings were held on an as-needed basis.  In
most cases, states hold an initial kick-off meeting when a conformity
cycle is beginning in order to discuss schedules, data, methodology, and
subsequent communications protocol.  Rural areas are discussed during
these meetings as needed.  

Data and Technical Analysis Methods

In isolated rural areas, network-based travel demand modeling is not
generally available, nor is it required by the transportation conformity
regulation. Rural areas typically rely on the Highway Performance
Monitoring System (HPMS) for VMT estimates, and MOBILE defaults for
fleet mix and other factors, since these are often the only sources of
data available for use in regional emissions analysis. A number of
states, however, noted that HPMS and the MOBILE defaults have
significant limitations for analyzing emissions in rural areas. 

The interviewees who expressed the most concern about the quality of
HPMS data generally were those that had experienced some problems
meeting conformity. These areas in particular had explored a number of
improvements to better estimate VMT and speed at a local level.

Limitations of HPMS for VMT Projections 

Several states noted the inadequacy of HPMS data for county level VMT
forecasts.  HPMS was not designed for use in county-level analysis.
Rather, it was designed as a statewide tool and is used nationally as an
indicator of road use and performance. As a result, VMT projections may
be very inaccurate for a rural county.  In the case of Paducah, KY,
motor vehicle emissions budgets that were developed based on HPMS data
significantly underestimated VMT growth, and updated VMT estimates
showed substantially higher VMT than assumed in the baseline. In
response, Kentucky has undertaken a number of modeling improvements to
better estimate VMT at the county level. Maine, Pennsylvania, and Ohio
also have developed or maintain road management systems that provide
detail beyond what is available from HPMS. 

Limitations of MOBILE Defaults for Rural Areas

Several states noted that defaults used within the MOBILE model (used to
generate emissions factors) do not always accurately reflect
“real-world” conditions in rural areas. In particular, the defaults
for the share of VMT on different types of roadways within the MOBILE
model can be inaccurate for rural areas.  For example, according to
staff at the Kentucky Transportation Cabinet, the MOBILE default values
indicate that 8% of interstate VMT is on ramps, which is generally
accurate for urban areas.  However, in Kentucky’s rural areas, the
ramps carry only about 1.5% of VMT. Several states also explained that
vehicle mix default data used in MOBILE are often inaccurate for rural
areas, and that in fact, the vehicle mix can vary substantially between
rural areas within a single state. In response, a number of states have
undertaken efforts to develop improved vehicle mix data for rural areas,
which is particularly important if heavy-duty vehicles comprise a large
portion of the vehicle travel.

The types of methodologies that states have used are described further
in Section 4 on Lessons Learned.

Preparations for New Standards

States are at different stages with regard to their preparation for the
8-hour ozone and PM-2.5 standards.  This situation was evolving during
the course of this research project. At the time that interviews for
this report were conducted many state DOTs were still uncertain about
the number of isolated rural non-attainment areas that might be
designated under new 8-hour ozone and PM-2.5 standards.  Some of this
uncertainty was associated with how specific nonattainment boundaries
would be drawn relative to new MPO boundaries.  Several states such as
Kentucky, South Carolina, and North Carolina are taking measures to
prepare for new standards, by training staff on new models, educating
rural officials about conformity and its potential impacts, and in some
cases establishing early action compacts.  Other states are waiting for
requirements and designations to be complete before investing in staff
preparations and/or education campaigns.  Some of the preparatory
actions being undertaken by sample states are described below:

Educating the Public and Local Officials about New Standards

The Kentucky Transportation Cabinet implemented a “Road Show”
awareness tour for the 8-hour ozone standard.  The purpose was to meet
with a wide range of local officials to discuss the forthcoming changes,
the benefits of good air quality, and the importance of being involved
in the process.  The state expects to see the rewards of this education
effort when new areas are designated nonattainment under the 8-hour
standard.  The purpose is to familiarize local officials with the air
quality requirements so they will better understand the implications of
not meeting conformity and focus more on cooperatively working through
the necessary steps, rather than being frustrated with the process.

Establishing New Interagency Agreements 

South Carolina has been particularly aggressive in pulling together
various counties and state agencies for a Memorandum of Agreement (MOA)
that defines agency relationships for the purpose of conformity.  The
concept is to include all MPOs, all potentially violating counties, and
all pollutants within an MOA, in order to prevent delay if it is
determined that some additional region or pollutant must later be
included in the conformity analysis. Getting buy-in from the necessary
authorities and preparing the legal documents for this process can take
longer than expected, and these MOAs are particularly important for
rural areas where it may be difficult to predict where new violations
occur.

Regional Information Sharing

Several states have increased their involvement with regional
organizations that function to share professional practices.  In
particular, state agencies mentioned Northeast States for Coordinated
Air Use Management (NESCAUM), the Midwest Regional Planning
Organization, and the Lake Michigan Air Directors Consortium (LADCO). 
These organizations include experienced modelers and emissions experts
that are able to assist one another when challenging issues arise.  The
state of Ohio specifically attributes its readiness to work with new
emissions models and conformity requirements to the support provided by
such organizations.  

Early Action Compacts

A number of states have entered into Early Action Compacts (EACs), which
were designed to defer nonattainment designations under the 8-hour ozone
standard in response to early actions to reduce emissions. Areas that
have Early Action Compacts will not be required to conduct
transportation conformity analyses under the 8-hour ozone standard so
long as they continue to meet the required milestones. Nevertheless,
several states are currently considering some variation of the
conformity process in Early Action Compact areas, calling it, 
“conformity without the red tape.”  This could have a significant
impact on the EAC areas because one of the principal reasons some areas
agreed to EACs was to get relief from conformity requirements. 

Efforts to Minimize Attainment Area Boundaries 

Several states are working with the U.S. EPA in an effort to minimize
the size of new ozone non-attainment areas.  Pennsylvania and Maine have
been particularly focused on this goal.  In many cases, an entire county
has been designated as an isolated rural area, when monitored data and
travel conditions imply that only a portion of the county has an air
quality problem.  Having countywide designations in these conditions may
create a situation where conformity is required for projects that may
have little or no relationship to the area where standards are being
violated. This is largely the case in nonattainment areas that receive
transported pollution from upwind areas. Nevertheless, because of the
regional nature of ozone, some argue for larger ozone nonattainment
areas.   

Air Agencies Encouraging Mobile Source Budget Restraint

Anticipating the challenges of meeting the new 8-hour ozone and PM-2.5
standards, a number of state air agencies have become more restrictive
in providing safety buffers for mobile source emissions budgets. These
air agencies believe that a large buffer may deter the state DOT from
exploring the full range of options for minimizing mobile source
emissions in rural areas, which may be necessary to meet the new
standards.  Where previously the state air agencies might consider only
the emissions reduction needs from other sources when allowing for
mobile source buffers, they now work to establish a compromise with
state DOTs that accommodates anticipated growth in VMT, but also
acknowledge potential for some mobile source reductions.

 Lessons Learned 

Based on the experience of states in conducting conformity analyses in
isolated rural areas and preparing for potential new nonattainment
areas, a few key lessons can be derived from this experience. This
section summarizes our synthesis of these lessons for practitioners, and
recommendations for areas that may soon be facing new isolated rural
nonattainment areas.

Transportation Staff Need to be Involved in Development of the SIP

One of the key lessons coming out of the interviews in this study is the
importance of having state DOT staff actively involved in and aware of
SIP development activities. In most isolated rural areas, with the
exception of PM-10 areas, there are few options for reducing vehicle
emissions in isolated rural areas.  As a result, having an attainable
emissions budget is critical to meeting conformity requirements for
those rural areas that have budgets. 

The importance of the State DOT working closely with the state air
agency to establish an emissions budget for motor vehicles that allows
for traffic growth cannot be overemphasized. Failure to provide for
adequate growth in VMT created a problem in meeting conformity in
Paducah, KY, which ultimately required the state to undertake a
time-consuming revision of the SIP budget. When the state DOT initially
provided VMT projections to the air agency, it did not clearly
understand how the projections would be used and the severe implications
of these projections for the emissions budget.

Moreover, DOTs should work with air agencies to ensure that the
emissions budget includes some safety buffer, if an emissions surplus
exists, to account for changes in methodologies and data that may occur
over time.  In many rural areas, the majority of travel occurs on very
few major facilities.  A rural project subject to conformity would
typically addresses capacity on one or more of these major facilities.
Since rural areas have low population and VMT, a small underestimate in
VMT forecasts for such facilities can lead to large percentage changes
in the overall VMT for the area, which in turn can create a problem
meeting the emissions budget.  Consequently, reasonable safety buffers
in mobile source emissions budgets should consider the potential for
increases in VMT, which may account for a small amount of pollution but
make an area unable to meet a budget. 

Most agencies described good coordination and flexibility on this
matter. Several states – in particular Maine and Ohio – described
cases where the DOT requested a safety buffer for mobile source
emissions in the SIP. While the air agencies did not provide all of the
requested mobile source budget increase, in both cases the agencies came
to an informed agreement following a discussion about the constraints
and other factors related to the SIP budget.  

Build Trust Between DOT and Air Agency Staff

Most states pointed to the importance of maintaining some type of
consistent contact and cooperative ethic between transportation and air
agencies. This is important both for resolving conformity problems as
they arise and more importantly to prevent problems from occurring in
the first place. Across the sample states, cooperation and trust were
achieved in a number of ways.

The exchange of professional staff between agencies is one factor that
seemed to enhance interagency communication. In several of the sample
states, practitioners had experience working in both the transportation
and the air agency.  This condition improved interagency understanding
and cooperation.  As such, agencies might consider a short-term exchange
program for staff members that play a role in transportation conformity.

In some cases, for example, South Carolina, both the DOT and air agency
have significant experience operating the MOBILE models. This appears to
have the effect of building a common vocabulary and mutual understanding
of analysis challenges and priorities that work in favor of effective
interagency relations. In other cases, regular meetings among
interagency staff helped to build relationships and facilitate good
working partnerships.

Some air agency staff noted that relationships as well as project
planning might be improved if air agencies were more involved in the
project selection process. For example, staff at one air agency felt
that they should have a larger role in the selection of CMAQ projects.
This had historically been the case, but at some point the State DOT
took complete responsibility for this task.  Since these projects are
expected to reduce emissions, it could be helpful to take into account
air agency perspective and expertise.  On the other hand, many states
noted that air agencies have very limited resources, and that the state
DOT takes on many responsibilities related to emissions modeling and
training staff on the MOBILE model, which are within the responsibility
of the air agency.

Be Aware of Data Limitations and Improvements to Address Them

Although the development of local data for factors such as speeds and
vehicle mix data is not required in isolated rural areas, staff involved
in the conformity process should be aware of the limitations of using
HPMS data and MOBILE model defaults alone to generate emissions
estimates in isolated rural areas. As noted in Section 3, there are
weaknesses to these methods. A number of states have developed
methodologies or data systems to improve forecasting in rural areas, and
these provide guidance on the types of activities that states can
undertake to improve their emissions estimates.  State and local
agencies involved in the conformity process for isolated rural areas
should decide through the interagency consultation process whether
improvements in data and methodologies justify the costs of making such
improvements.  Several of these methods are discussed below.

VMT Forecasts

Since isolated rural areas typically do not have a travel demand model,
improvements in VMT forecasts can be made by separately estimating
local-VMT and through-VMT.  Most of the sample states in this study used
such a methodology. Local-VMT refers to travel by residents of the
county, which generally increases in proportion to the population. 
Local-VMT is projected using per-capita VMT estimates along with
population projections.  An important factor in these projections is the
growth rate in per capita VMT. Through-VMT refers to vehicles passing
through the county, which generally increases in proportion to
inter-county or even interstate travel. 

In most rural counties, inter-county travel tends to increase faster
than local travel, so strictly population based VMT growth rates would
usually underestimate VMT.  Where interstates are present in rural
counties, it is wise to assess interstate VMT growth rates
independently.  For example, Kentucky found that VMT growth rates were
nearly double in rural counties that had an Interstate compared to rural
counties without an interstate. South Carolina has documented its
methodology for VMT growth projections in rural areas, which may be
useful to other practitioners (listed in Section 5 of this document). 

Vehicle Fleet Mix and Roadway Distributions

MOBILE model defaults may not always accurately reflect “real-world”
conditions in rural areas and may not always assign the appropriate
factors for vehicle fleet mix and VMT by roadway type. State DOTs may
have a better source of data to develop these factors, since they should
have access to relatively current and geographically specific vehicle
mix data from the state motor vehicle department.  With heavy-duty
vehicles comprising an important portion of emissions, accurate
identification of this component of the vehicle mix is vital.  Ohio DOT
makes use of their Statewide Economic Census Vehicle Inventory and Use
Survey.  This forms a critical component of their vehicle mix data since
it presents the best source of geographic-specific heavy-duty vehicle
information.  Although most states do not have as detailed a heavy-duty
vehicle inventory as Ohio, the national Vehicle Inventory and Use survey
can be helpful where a rural county includes an important truck
corridor. Information about the survey is available through the Census
Bureau. 

Speed Estimation

Vehicle emissions predicted by MOBILE are sensitive to vehicle speed
inputs.  Consequently, accurate speed estimates should be a priority for
regional emissions analysis.  Speeds have been traditionally estimated
based on posted speeds, or derived using methods described in the
Highway Capacity Manual (HCM).  These HCM methods use hourly traffic
volumes and capacities by roadway functional classification. While such
approaches provide reasonable estimates of speeds, speed studies could
also be conducted in order to collect field data, which would be better
than published default values or posted speed limits. A number of states
have undertaken efforts to correct generic speed categories with more
extensive local field data. These efforts need not be resource
intensive. For example, about 40 hours of staff time were required in
South Carolina for data collection and analysis for a speed study on a
sample of urban, suburban and rural highways in Cherokee County.
Research by the South Carolina DOT found that in rural areas, improved
estimates of free-flow mean speeds were much more important than
improved estimates of congested speeds, and that applying a speed-flow
formula to estimate “congested” speeds complicates the analysis with
minimal change in predicted mean speed on many road classifications
since most rural areas have limited congestion.   

Several resources are available to assist with speed estimation and
other procedures.  A good explanation focusing on rural applications can
be found in a report titled Development of On-Road Mobile Source
Emission Inventories for Rural Counties.  Rural speed estimation is also
covered in the National Highway Institute course titled, Estimating
Regional Mobile Source Emissions. Several states have had success in
using equations described in NCHRP Report 387, Planning Techniques to
Estimate Speeds and Service Volumes for Planning Applications.  

Local Government Data

In some cases, data to help develop improved VMT, speed, and fleet
characterization estimates may be available from local governments. 
Both Oregon and Colorado rely heavily on local agencies for lane-miles,
speed, and VMT data.   The availability of such data is probably related
to the level of transportation planning that occurs in rural areas.  In
the case of Oregon, all counties with population above 25,000 are
required to develop Transportation Systems Plans that necessitate
collecting such data.  In Colorado, Regional Planning Commissions
prepare 25-year long range plans for all non-MPO areas. State DOTs
should be aware of the extent to which rural transportation planning
agencies may provide better data before using defaults. 

Statewide Travel Demand Forecasting Model

States may also wish to consider developing a statewide travel
forecasting model. More advanced VMT forecasting techniques also take
into account current and anticipated economic trends and anticipated
changes in population age distribution for a range of household
characteristics.  Maine DOT incorporates these factors into their
statewide travel demand forecasting model, which produces different VMT
growth rates by county.   Ohio DOT is currently developing a statewide
model that it believes will allow for more efficient and more accurate
mobile source emissions estimates for conformity. 

Build Institutional Memory and Expertise

States agencies should prepare for the future by becoming familiar with
the conformity regulations and flexibility available for isolated rural
areas.  The interviews for this research revealed that considerable
effort was required in most of the seven sample states to understand how
to undertake conformity analysis in isolated rural areas. In some cases,
practitioners had difficulties understanding what types of tests needed
to be conducted and when analyses needed to be conducted. Therefore,
clearly understanding the conformity requirements, and flexibility
available to isolated rural areas, is important, particularly in states
with few existing nonattainment areas. As noted in Section 3, some
states are actively preparing for potential new nonattainment areas by
undertaking educational and outreach efforts and developing memoranda of
agreement.

Moreover, given that conformity analyses take place infrequently in
isolated rural areas, it is important to have mechanisms to build
institutional memory and expertise. Several State DOTs emphasized the
importance of being meticulous in documenting interagency agreements. 
They emphasized that agreements on seemingly minor issues may turn out
to be critical, and that everything should be in writing.  This serves
not only for legal cover, but also for institutional memory.  Staff
turnover can be particularly problematic because of the infrequency of
rural conformity determinations. This became evident even in discussing
projects for this research.  A number of staff did not have conformity
determination reports available, and in many cases, the person that
worked on the document was no longer at the agency. In this way,
documentation is therefore perhaps more important in isolated rural
areas than in metropolitan areas.  

Conclusion

Conformity requirements are complex and significant preparation time is
needed to develop the expertise, tools, and interagency relationships
that facilitate an efficient and effective process. In most cases, the
state DOT is in the best position to lead conformity analysis, rather
than rural counties. In our review of seven states’ experience with
conformity in isolated rural areas, several state DOTs encountered
significant technical and procedural challenges in conducting these
analyses, while others had relatively few difficulties. In general, the
difficulties did not relate to problems in reducing emissions in
nonattainment areas. They typically stemmed from limited familiarity
with the conformity requirements and limited coordination between
transportation and air agencies. 

States agreed that good relationships between state DOTs, state air
agencies, and federal partners are paramount to a successful process. In
most cases, rural areas produce small levels of transportation related
emissions and have very few opportunities to reduce motor vehicle
emissions. As a result, it is extremely important for state DOTs and air
agencies to work together to develop an emissions budget in the SIP that
is attainable by accounting for potential future VMT growth and
potential changes in calculation methodologies. Coordination early on in
the SIP development process will help to avoid potential problems in the
future. There are also a number of steps that states can take to prepare
for conformity in rural areas that do not have transportation models,
including data collection to improve estimates of VMT and speeds in
rural areas, developing interagency agreements, and educating public
officials about conformity and air quality issues. 

Resources / References

This section includes a list of useful resources that practitioners may
wish to review in order to gain a better understanding of conformity
requirements and methodologies for regional emissions analysis. It also
includes recent research, including case studies, on the conformity
process in rural and metropolitan areas.

Legislation/Requirements, Guidance, and Training

Conformity Requirements: Title 40 of the Code of Federal Regulations (40
CFR Parts 51 and 93) <  HYPERLINK
"http://www.access.gpo.gov/nara/cfr/waisidx_99/40cfr93_99.html" 
http://www.access.gpo.gov/nara/cfr/waisidx_99/40cfr93_99.html >

Transportation Conformity: A Basic Guide for State and Local Officials,
U.S. Federal Highway Administration, Revised June 19, 2000.  < 
HYPERLINK "http://www.fhwa.dot.gov/environment/conformity/con_bas.htm" 
http://www.fhwa.dot.gov/environment/conformity/con_bas.htm >

Transportation Conformity Reference Guide. Federal Highway
Administration (last updated July, 2001) <  HYPERLINK
"http://www.fhwa.dot.gov/environment/conformity/ref_guid/index.htm" 
http://www.fhwa.dot.gov/environment/conformity/ref_guid/index.htm > 

Clean Air Act (42 USC 7401-7671q) <  HYPERLINK
"http://www.epa.gov/oar/caa/contents.html" 
http://www.epa.gov/oar/caa/contents.html >

SIP Requirements <  HYPERLINK "http://www.epa.gov/oar/caa/contents.html"
 http://www.epa.gov/oar/caa/contents.html >

National Transit Institute (NTI) Course on Introduction to
Transportation/Air Quality Conformity

<  HYPERLINK "http://www.ntionline.com"  http://www.ntionline.com >

National Highway Institute (NHI) Course on Estimating Regional Mobile
Source Emissions

<  HYPERLINK "http://www.nhi.fhwa.dot.gov"  http://www.nhi.fhwa.dot.gov
>

Other FHWA/EPA Conformity Resources, including Transportation Conformity
Community of Practice

<  HYPERLINK "http://www.fhwa.dot.gov/environment/conform.htm" 
http://www.fhwa.dot.gov/environment/conform.htm >

Methodologies

Development of On-Road Mobile Source Emission Inventories for Rural
Counties, G. B. Dresser, D. G. Perkinson, Texas Transportation
Institute, May 2001. <  HYPERLINK
"http://www.epa.gov/ttn/chief/conference/ei10/index.html#ses-6" 
http://www.epa.gov/ttn/chief/conference/ei10/index.html#ses-6 >

Highway Speed Estimation for MOBILE6 by Bob Bostrom and Jesse Mayes,
Kentucky Transportation Cabinet.

Planning Techniques to Estimate Speeds and Service Volumes for Planning
Applications, National Cooperative Highway Research Report Program
Report 387, Transportation Research Board, Dowling, R.; Kittelson, W;
Zegeer, J.; Skabardonis, A, 1997.

Vehicle Miles of Travel Projections and Speed Estimates for Rural
Nonattainment and Maintenance Areas, John Gardner, South Carolina
Department of Transportation, presented at Southern Transportation and
Air Quality Summit, October 2001, Atlanta, Ga.

Research

Exhausting Options: Assessing SIP-Conformity Interactions, Winston
Harrington, Arnold Howitt, Alan J. Krupnick, Jonathan Makler, Peter
Nelson, and Sarah J. Siwek, Resources for the Future, January 2003.
<http://www.fhwa.dot.gov/environment/conformity/con_res.htm>

Linking Transportation and Air Quality Planning: Implementation of the
Transportation Conformity Regulations in 15 Nonattainment Areas. Arnold
M. Howitt and Elizabeth M. Moore, Prepared for U.S. Environmental
Protection Agency (EPA 420-R-99-011), March 1999. <  HYPERLINK
"http://www.epa.gov/otaq/transp/conform/fullrpt.pdf" 
http://www.epa.gov/otaq/transp/conform/fullrpt.pdf >

Regulating Transportation in New Nonattainment Areas Under the 8-hour
Ozone Standard, Jonathan Makler and Arnold M. Howitt, Transportation
Research Board Annual Meeting, January 2003. <http://www.ksg.  HYPERLINK
"http://www.ksg.harvard.edu/taubmancenter/research/trenv.html"  harvard
.edu/taubmancenter/research/trenv.html>

Transportation/Air Quality Issues in Rural Areas, prepared by Dye
Management for the Federal Highway Administration, June 2003.

Appendix A: Interview Guide

Introductory Questions: 

Can you briefly summarize the situation in your state regarding existing
rural nonattainment or maintenance areas?  

Can you summarize the changes in attainment status that you anticipate
for rural areas once the new 8-hour ozone and PM 2.5 requirements have
taken effect? 

Interview Questions for Existing Nonattainment / Maintenance Areas:

Describe your experience with rural transportation conformity.

How many conformity analyses have been conducted over the past 5 years?

What was the role of the State DOT, the regional FHWA and EPA offices,
the air quality planning agency, rural counties, and other agencies?

[For those who have been involved in conformity analysis]  Have you
experienced difficulties in demonstrating conformity that resulted in
the area not being able to implement/approve a new transportation
project?  If yes, for how long was this project delayed? 

What have state and local agencies done to resolve any transportation
planning, air quality planning, or conformity challenges related to
specific projects?

For particular rural isolated areas:

What federal actions/measures (e.g., federal vehicle emissions controls;
fleet turnover) are helping the area attain or maintain the air quality
standard(s)? 

What are the projected population and VMT growth rates in this isolated
rural area?

Describe the technical issues involved in establishing conformity in
isolated rural areas?

How did you prepare the necessary baseline data and projections for the
conformity analysis?

What were the sources for VMT, speed, lane-miles, and emissions data?
Which agency provided such information?  At what scale was it available?
 What data was easily obtained, what data was difficult to obtain, and
why?

What methods are available to estimate regional emissions in rural
areas?

Do you have the ability to assess localized impacts for CO and PM?  How?

How did you define projects that were still under development well
enough to determine emissions?

Describe the interagency consultation process. How did interagency
coordination occur? Which agency took the lead in interagency
consultation?

What opportunities or processes are in place to encourage coordination
between state transportation officials, local transportation officials,
and air quality officials?

How often did you meet with state environmental agencies, FHWA and EPA
division staff?

What agencies are involved in the approval process for conformity plans
in rural areas?

How do you currently engage with the SIP process?  

What was the nature of your participation in development of the last
SIP?  What, if any, are the barriers to your involvement? How did
conformity change the role of the State DOT or local government in SIP
planning?

What information is available to decision-makers in determining the most
practical distribution of emissions reduction targets?

What is currently known about the sources of criteria pollutants that
are responsible for nonattainment?  Is the role of on-road mobile
sources well understood?  If not, are there efforts underway to gather
this information?

Did the conformity process change ways that you do air quality and
long-term transportation planning in rural areas?

Describe how members of the public and other stakeholders were involved
in the process.

If you were to provide guidance to other rural areas that will need to
address conformity due to the new ozone and PM2.5 standards, what kind
of advice or recommendations would you give them?

Interview Questions for Expected New Nonattainment Areas:

What are you currently doing to prepare for nonattainment status in
rural areas?

Do you have any training in doing conformity?  

What are your technical capabilities in transportation and emissions
planning and modeling?

Have you defined what the role of the state DOT, air agency, and/or
local planning agency will have when conformity applies?

Who will be the lead agency for project conformity determinations and
analyses?

What is the current role of the State DOT?

What is the current role of the State air agency? 

Have you discussed what VMT, speed, and emissions data will be used in
the event that a project requires NEPA approval and a conformity
determination?

Based on existing information, what are the primary sources of pollution
in your area? 

How many projects have you approved in the last 5 years? 

Do you anticipate having any projects that require NEPA approvals in the
next 5 years?

What additional assistance would be most valuable in helping you prepare
to meet conformity requirements?  Have you heard of any steps in the
state that sound like they are good examples of preparatory measures
(e.g., training, data compilation, agency coordination and agreements)?

Appendix B: Contact Information 

This section will include a list of people that were interviewed for
this study. 

State	Contacts

Colorado 

		Jerry Piffer, 

Environmental Programs

Colorado DOT

Mike Silverstein

Colorado Air Pollution Control District

Department of Public Health and Environment



Kentucky	Lynn Soporowski

Division of Multimodal Programs

Kentucky Transportation Cabinet

Jesse Mayes

Division of Multimodal Programs

Kentucky Transportation Cabinet

Charles Schaub

Division of Multimodal Programs

Kentucky Transportation Cabinet

Barry House

Division of Multimodal Programs

Kentucky Transportation Cabinet

John Gowins

Program Planning and Administration Branch

Kentucky Division for Air Quality



Maine	Lori Brann

Bureau of Planning

Maine DOT

Duane Scott

Bureau of Planning

Maine DOT

Melissa Morrill

Air Bureau

Maine Department of Environmental Protection

Donald Cooke (brief questions)

Region 1

U.S. EPA 



North Carolina*	David Hyder

Office of Human Environment

North Carolina DOT

Edward Dancausse

Program Planning and Development

FHWA, North Carolina Division



Ohio	Dave Moore

Office of Urban and Corridor Planning

Ohio DOT

Bill Spires

Division of Air Pollution Control

Ohio Environmental Protections Agency



Oregon	Vince Carrow

Environmental Services

Oregon DOT

David Nordberg

Air Quality Division

Oregon Department of Environmental Quality

David Collier

Air Quality Division

Oregon Department of Environmental Quality

Ralph Johnston

Lane Regional Air Pollution Authority



Pennsylvania	Michael Baker

Air Quality Section

Pennsylvania DOT

Arleen Shulman

Mobile Sources Division

Pennsylvania Department of Environmental Protection



South Carolina	John Gardner

Office of Planning

South Carolina DOT

Henry Phillips

Bureau of Air Quality

South Carolina Department of Health and Environmental Control

Mike Roberts

Resource Center

FHWA





*Note: Interviews were conducted in North Carolina as a test of the
interview protocol. Findings were not highlighted in this report because
North Carolina does not contain any isolated rural areas; it does,
however, contain a number of rural donut areas.

 A nonattainment area is a region that does not meet (or that
contributes to ambient air quality in a nearby area that does not meet)
the national ambient air quality standard (NAAQS) for any of the six
criteria pollutants. The area must take specified actions within a
certain time frame to reduce emissions and attain the standard. A
maintenance area is a region previously designated as nonattainment, and
subsequently redesignated to attainment.

 Dye Management. Transportation/Air Quality Issues in Rural Areas.
Prepared for Federal Highway Administration, June 2003.

 23 CFR 450 Part 613, 58 FR 58040, Oct. 28, 1993.

 In addition, compliance with the planning requirements of Title 23 and
49 U.S.C. is integral to making a conformity determination. These
requirements include demonstration of a fiscally constrained plan and
TIP.

 1990 is the baseline year for existing nonattainment and maintenance
areas. A “less than 1990” test is used for moderate and above ozone
nonattainment areas that are subject to the reasonable further progress 

requirements of CAA section 182(b)(1), in moderate CO areas with design
value greater than 12.7 ppm, and in serious CO nonattainment areas. A 
“no greater than” (less than or equal to) 1990 test is used for
other areas. For newly designated areas, 2002 has been proposed as the
baseline. 

 The “build/no build” test is referred to as the
“baseline/action” test in 40 CFR 93.119.  The term build/no build is
used through this report.

 23 USC 134 and 135 codified in 23 CFR 450.

 This is the same analysis as the plan analysis.

 Regionally significant project is defined as a transportation project
(other than an exempt project) that is on a facility which serves
regional transportation needs (such as access to and from the area
outside of the region, major activity centers in the region, major
planned developments such as new retail malls, sports complexes, etc.,
or transportation terminals as well as most terminals themselves) and
would normally be included in the modeling of a metropolitan area's
transportation network, including, at a minimum, all principal arterial
highways and all fixed guideway transit facilities that offer an
alternative to regional highway travel. See 40 CFR 93.101 (Definitions).

 See 40 CFR 93.126 (Exempt projects), 40 CFR 93.127 (Projects exempt
from regional emissions analyses) and 40 CFR 93.128 (Traffic signal
synchronization projects).

 The requirement that donut area emissions be included in the regional
emissions analysis conducted by the associated MPO may not be applicable
where there are sub-area emissions budgets for the donut area.

 Metropolitan planning areas are designated under 23 U.S.C. 134 and 49
U.S.C. 5303.

 Requirements for metropolitan plans and TIPs are described under 23
U.S.C. 134 and 49 U.S.C. 5303 and 5304.

 These frequency requirements are described in 40 CFR 93.104.

 The attainment date is the date by which an area is required to meet
air quality standards.

 This table, and other parts of the report occasionally refer to areas
that are required to submit SIPs. Technically speaking, it is the State
that is required to submit the SIP.

 FHWA’s PM10 qualitative analysis guidance can be found at:  
HYPERLINK "http://www.fhwa.dot.gov/environment/conformity/hspotmem.htm" 
http://www.fhwa.dot.gov/environment/conformity/hspotmem.htm  

 The current EPA-approved emissions model is MOBILE6 in all states
except California.

 Although donut areas were not the focus of our study, we also found
that State DOTs played a lead role in conformity analyses in rural donut
areas in North Carolina, Ohio, Kentucky, and Pennsylvania. This was
somewhat surprising since the conformity requirements stipulate that
regionally significant projects in donut areas must be incorporated into
the MPO’s regional emissions analysis. In these cases, through the
interagency consultation process, it was agreed that the State DOT would
analyze emissions associated with the projects outside the MPO boundary
and combine these results with the MPO analysis. 

 A local agency, in this context, refers to any government agency whose
jurisdiction is below the state level.   This is not intended to include
local branches of state agencies such as DOT district or regional
offices.

 Pennsylvania has six regional planning and development organizations in
rural areas.  These are known as local development districts (LDDs). 
LDDs were initiated through the state DOT’s rural transportation
planning program in FY 1992-93 to complement the ongoing metropolitan
activities.  Each LDD has a technical committee that reviews conformity
plans, and an approval body that receives a recommendation from the
technical committee.  LDDs also assist the state DOT with long-range
planning, Congestion Management System planning, and collection of
Highway Performance Monitoring System data, and assist in advancing
projects through needs assessments, environmental studies and public
involvement.

 Note the approved emissions models predict the fleet mix for future
years, so although the vehicle fleet might be modernizing while a
project is delayed; this would not generally affect future year
emissions projections.  However, the project delay and concurrent fleet
modernization could help when an area is not meeting the budget for the
current year.

 A South Carolina assessment of rural communities, for example, found
that Tier II and low sulfur fuel standards are likely to eliminate many
ozone and PM violations in the longer-term (sometime after 2007).  The
greatest concern is the near-term during which increasing VMT and the
new ozone and PM-2.5 standards will create new violations before Tier II
and low sulfur fuel standards have their full, mitigating effect.

 In addition, there may be questions about EPA’s legal authority to
defer nonattainment designations, which is central to the point of EACs.
 This has not been litigated thus far; however, some professionals
anticipate that there may be litigation over this matter.

   HYPERLINK "http://help.econ.census.gov/econhelp/vius/vius_FAQS.html" 
http://help.econ.census.gov/econhelp/vius/vius_FAQS.html 

 Sensitivity Analysis of MOBILE6 Motor Vehicle Emission Factor Model,
Tianjia Tang, Mike Roberts, and Cecilia Ho, Federal Highway
Administration Resource Center, Atlanta. <  HYPERLINK
"http://www.fhwa.dot.gov/resourcecenter/teamaq_pubs.htm" 
www.fhwa.dot.gov/resourcecenter/teamaq_pubs.htm >

 A more complete summary of speed estimation techniques has been
developed by the Kentucky Transportation Cabinet Office of Multimodal
Planning <  HYPERLINK "http://www.kytc.state.ky.us/Multimodal/doc/" 
www.kytc.state.ky.us/Multimodal/doc/ > under “Summary of Travel Model
Speed Estimation.”

 Vehicle Miles of Travel Projections and Speed Estimates for Rural
Nonattainment and Maintenance Areas, John Gardner, AICP, South Carolina
Department of Transportation.

 G. B. Dresser, D. G. Perkinson, Texas Transportation Institute.
Development of On-Road Mobile Source Emission Inventories for Rural
Counties. Available at <  HYPERLINK
"http://www.epa.gov/ttn/chief/conference/ei10/index.html#ses-6" 
www.epa.gov/ttn/chief/conference/ei10/index.html#ses-6 >, listed as 

 <  HYPERLINK
"http://tmip.fhwa.dot.gov/clearinghouse/docs/newsletters/jan03_issue15.s
tm#nhi_course" 
http://tmip.fhwa.dot.gov/clearinghouse/docs/newsletters/jan03_issue15.st
m#nhi_course >

 Dowling, R.; Kittelson, W; Zegeer, J.; Skabardonis, A.; National
Cooperative Highway Research Report Program Report 387: Planning
Techniques to Estimate Speeds and Service Volumes for Planning
Applications; Transportation Research Board, 1997.

 Maine’s VMT, speed forecasting approaches are effectively summarized
in section five of the Maine DOT 2002 - 2004 STIP Conformity Analysis,
August 2001.  Available on-line at <  HYPERLINK
"http://www.maine.gov/mdot/planning/air_qual/ca_docs.htm" 
http://www.maine.gov/mdot/planning/air_qual/ca_docs.htm >

 PAGE   6 

NCHRP 8-36(28)		ICF Consulting

Rural Conformity: A Survey of Practice	Final Report – October 31, 2003

 PAGE   38 

Difference in Frequency of Conformity Analysis

In Metropolitan Areas:

Conformity determinations must be made at least every three years

In Isolated Rural Areas:

Conformity determinations must be made only prior to FHWA or FTA
approval of a non-exempt project.

Situation:

An isolated rural area has been redesignated to maintenance from its
original classification as a marginal ozone nonattainment area.  The
rural area has a maintenance plan for ozone, with an end year of 2007.
The maintenance plan includes an emissions budget for NOX and VOC
emissions for 2007. A non-exempt project has been included in the STIP
within the maintenance area, requiring a conformity determination in
2003.

Regional Emissions Analysis Years:

A regional emissions analysis must be conducted for the following years:

2007 – end year of maintenance plan; 

2015 – interim analysis year

2023 – analysis year 20 years in the future

Regional Emissions Analysis Tests:

For the 2007 analysis, the budget test is required because there is an
adequate budget.

For the 2015 and 2023 analyses, a choice of tests can be made:

Budget test using 2007 budget, OR

Build/no build test OR no-greater-than-1990 test, OR

Air dispersion or other air quality modeling used in the attainment
demonstration or maintenance plan and agreed to through the interagency
consultation process. 

Conformity analyses are conducted infrequently in most isolated rural
areas.

State DOTs tend to play the lead in conducting conformity analyses in
isolated rural areas; local agencies have played a role in only some
areas.

In many isolated rural areas, meeting conformity has not been a problem,
largely due to federal or state emission reduction measures.  In several
cases, however, states faced project delays and procedural difficulties;
many of these related to lack of familiarity with conformity
requirements. 

State DOT staff expressed concern that conformity in isolated rural
areas takes a disproportionate amount of time and resources compared to
its actual effects on air quality. On the other hand, the transportation
conformity process has motivated increased coordination between air
agencies and DOTs and has fostered an awareness of the air quality
effects of different types of projects.

In isolated rural ozone areas, there are limited options for reducing
project-related emissions.  However, there are some opportunities,
particularly in PM-10 areas and resort areas. 

The interagency consultation process appears to be working effectively,
but in many cases took significant time and preparation to develop the
process.

Simple sketch planning methods, using HPMS data and MOBILE default
values, are commonly used for conformity analyses in rural areas.
However, there are significant limitations to these sources, and a
number of states have developed more refined methods, partly in response
to potential conformity problems.  

It is critically important for State DOTs to be involved in the
development of SIPs and the motor vehicle emissions budget in rural
areas.

It is important to build trust between state DOT and air agency staff in
order to have an effective and collaborative process.

Staff should be aware of the limitations of HPMS data and MOBILE default
values for use in isolated rural areas, and consider methods to develop
more accurate emissions estimates where appropriate.

It is important to build institutional memory and expertise in order to
reduce the potential for increased effort and delay in meeting
conformity.  

