Report to Congressional Requesters

United States General Accounting Office 

GAO 

April 2003 ENVIRONMENTAL 

PROTECTION 

Federal Planning 

Requirements for 

Transportation and 

Air Quality Protection 

Could Potentially Be 

More Efficient and 

Better Linked 

GAO-03-581 
Since 1997, 56 of the 159 transportation planning areas with air quality problems 

failed to demonstrate conformity by a required deadline at least once, according 

to federal agency data, but only five areas had to change their transportation 

plans as a result. About half of the areas failed because of resource, 

administrative, or technical problems, such as a lack of time and staff, and 

resolved the problem in 6 months or less. About one-third of the 253 

transportation planners responding to our survey said they anticipate having 

trouble demonstrating conformity in the future, especially in meeting the more 

stringent limits on two pollutants resulting from vehicle emissions—ozone and 

fine particulate matter. 

A majority of transportation planners who had trouble demonstrating 

conformity or failed to do so by a deadline said that the required frequency of 

demonstrations robs them of time and resources to solve other issues, such as 

growing congestion. The planners support extending the current 3-year time 

frame between required updates of the 20-year plan, which could also result in 

less frequent conformity demonstrations. Under this change, areas would still 

demonstrate conformity of their TIP every 2 years, and could still update and 

demonstrate conformity on their long-term plans more frequently than required, 

such as to add new projects or shift funds. These factors could help to ensure 

that the change would not have a significant impact on the conformity process’ 

role to protect air quality. 

 

Transportation planners also noted the difference between their frequent plan 

updates, which must use the latest emissions model and data (such as the types 

of vehicles on the road and the number of miles they travel), and air quality 

plans, with their associated emissions budgets, which are not required to be 

updated with the current model or data. The transportation planners said this 

creates conflicts and can result in ineffective changes to an area’s transportation 

plans. Any proposal to require that air quality plans be regularly updated, 

however, needs to weigh the benefits against the fact that such updates are 

difficult and costly. 

Length of Conformity Lapses, 1997-2002 

To protect the public from harmful 

emissions, transportation planners 

in areas with poor air must show 

that their plans will not make it 

worse. Every time they update their 

transportation improvement 

program (TIP) and their 20-year 

plan—every 2 and 3 years 

respectively—federal laws and 

regulations require that they ensure 

the emissions from their plans will 

not exceed the mobile source 

emissions budget. This is known as 

“demonstrating conformity.” Areas 

that fail to do so generally cannot 

spend federal funds on new 

projects until they resolve the 

problem. The Committee asked 

GAO to determine (1) how many 

areas have failed, why, and what 

corrective actions they took, and 

(2) what issues transportation 

planners had with the conformity 

process and what solutions are 

possible. 

To help improve the conformity 

process, GAO recommends that the 

relevant federal agencies (1) 

consider extending the 3-year time 

frame between required 

transportation plan updates and 

asking the Congress to amend the 

Clean Air Act to change the 

conformity rules to match, and (2) 

assess the advantages and 

disadvantages of statutorily 

requiring that the emissions 

budgets in air quality plans be 

regularly updated with new travel 

data and emissions models. DOT 

and EPA generally agreed with 

these recommendations. 

www.gao.gov/cgi-bin/getrpt?GAO-03-581.

To view the full report, including the scope 

and methodology, click on the link above. 

For more information, contact John 

Stephenson at (202) 512-3841. 

Highlights of GAO-03-581, a report to 

Congressional Requesters 

April 2003

ENVIRONMENTAL PROTECTION 

Federal Planning Requirements for 

Transportation and Air Quality Protection 

Could Potentially Be More Efficient and 

Better Linked 
Page i GAO-03-581 Environmental Protection 

Letter 1

Results in Brief 3

Background 6

Few Areas Have Needed to Change Transportation Plans to 

Resolve a Conformity Lapse, but More May Need to Do So in the 

Future to Meet New Standards 13

Frequency of Demonstrating Conformity and Inconsistent 

Requirements for Updating Transportation and Air Quality Plans 

Cause Problems 21

Conclusions 27

Recommendations for Executive Action 28

Agency Comments and Our Evaluation 29

Appendix I Objectives, Scope, and Methodology 31 

Appendix II Survey of Local Transportation Planners 35 

Appendix III Survey of State Air Quality Planners 54 

Figures 

Figure 1: Counties in Nonattainment or Maintenance Status for at 

Least One Criteria Pollutant 8

Figure 2: Process for Forecasting Future Travel Demand 10

Figure 3: Length of Conformity Lapses, 1997-2002 14

Figure 4: Primary Causes of Conformity Lapses, 1997-2002 15

Figure 5: Primary Solutions to Conformity Lapses, 1997-2002 17

Figure 6: Counties Expected to Violate the New Ozone Standard 

for the First Time 19

Contents 

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Page 1 GAO-03-581 Environmental Protection 

April 28, 2003 

The Honorable James M. Jeffords 

Ranking Minority Member, 

Committee on Environment and Public Works 

United States Senate 

The Honorable Joseph I. Lieberman 

United States Senate 

As the nation has grown, so has its dependence on cars as its primary 

mode of transportation. Over the past 30 years, the volume of miles 

traveled on the nation’s roadways in these vehicles has increased four 

times faster than the total population. Although they contribute to the 

increased mobility of the population, these vehicles also burn fuel that 

emits harmful pollutants into the air, thereby posing risks to public health 

and the environment. Clean Air Act provisions, as well as technological 

advances with cleaner vehicles and fuels, have helped to significantly curb 

these emissions over this same time period. But because of continued 

growth and increased travel, states and localities must continue to monitor 

and control these emissions to achieve or preserve clean air. 

In an effort to protect public health from such emissions, the 

Environmental Protection Agency (EPA) has set ambient air quality 

standards, or limits, on the amount of certain harmful pollutants, such as 

ozone, carbon monoxide, and particulate matter, which can be present in 

the air. The Clean Air Act requires the states to develop air quality 

protection plans to implement, maintain, and enforce these standards. 

These plans define the amount of these pollutants that four main sources 

can emit—surface transportation, such as cars, trucks, and buses (on-road 

mobile sources); other vehicles, such as construction equipment, train 

engines, and airplanes (non-road mobile sources); industry, such as 

factories and power plants (point sources); and business, such as dry 

cleaners or bakeries (area sources). For the on-road mobile source sector, 

this limit on emissions is known as a “motor vehicle emissions budget.” 

Transportation planners in areas where emissions exceed the standards or 

did so in the past are required by the Clean Air Act to consider these 

budgets when developing their two primary documents outlining their 

future transportation network. The first is a long-range plan that specifies 

a 20-year vision for a metropolitan area’s transportation system; the 

United States General Accounting Office

Washington, DC 20548 
Page 2 GAO-03-581 Environmental Protection 

second is a short-range transportation improvement program (TIP) that 

specifies the priority projects to be implemented in the next 3 years in 

more detail. These transportation planners are required to update their 

plans at least once every 3 years, and their TIPs at least once every 2 years. 

Each time they conduct these updates, federal laws and regulations 

require the planners to demonstrate that the estimated emissions from the 

planned transportation system, including projects in the plan or TIP, will 

not exceed the emissions budgets in the state air quality plans. This is 

known as “demonstrating conformity.”1

 The planners must submit their 

demonstrations to the Department of Transportation (DOT), which is 

responsible for ensuring it conforms to the air quality plan, in coordination 

with EPA. If DOT determines that an area has not passed its conformity 

demonstration by specified deadlines, the area enters into what is known 

as a “lapse.” During a lapse, an area generally can only spend federal 

transportation funds on certain projects, such as safety, mass transit, and 

air quality projects, until it resolves the problem and can demonstrate 

conformity. 

The ease or difficulty with which transportation planners complete the 

conformity process, especially in light of upcoming changes to air quality 

standards, has prompted interest in reviewing this process. EPA will soon 

implement two new and more stringent standards, or limits, on ozone and 

fine particulate matter—two substances prevalent in or created by vehicle 

emissions—that will subject some areas of the country to the conformity 

process for the first time. In addition, as some of the nation’s developed 

areas balance the pressures of a growing population, urban sprawl, and 

congested roadways, areas already having to demonstrate conformity may 

find compliance an even greater challenge. 

As the Congress reauthorizes the nation’s major surface transportation 

law, it is interested in knowing how well the conformity process is 

working and what effect, if any, it is having on an area’s transportation 

plan, projects, and federal funding. A number of transportation 

stakeholders have studied various pieces of the conformity process and 

have offered reauthorization proposals to make changes to it. You asked 

us to focus on three such proposals that, among other things, would 

streamline the transportation planning process and in turn affect the 

 1

 DOT conformity program managers noted that a number of additional factors, other than 

updating transportation plans and TIPs, such as the approval of a new or revised motor 

vehicle emissions budget or certain other changes to air quality plans, can also trigger a 

required conformity demonstration. 
Page 3 GAO-03-581 Environmental Protection 

required steps in the conformity process. Two of the proposals would 

extend the time between required updates of the plan and TIP, thereby 

extending the time between the associated conformity demonstrations, 

respectively, and the third would combine these two plans into a single 

planning document, subject to a single conformity demonstration. 

More specifically, you asked us to determine (1) how many areas of the 

country have had their conformity status lapse at least once since 1997 

(the earliest date for which data are available), why, and what corrective 

actions were taken, and (2) what issues planners have encountered during 

the conformity process and the extent to which each of the proposed 

changes to the transportation planning process will address these issues. 

In responding to the first objective, we reviewed the reliability of all 

available data from EPA and DOT on areas that have experienced a 

conformity lapse. EPA began collecting these data on a regular basis in 

1997 and DOT in 1999. In responding to the second objective, we 

conducted a Web-based survey of all 341 local transportation planning 

organizations nationwide, commonly known as Metropolitan Planning 

Organizations, and all air quality planning agencies in the 50 states plus the 

District of Columbia and Puerto Rico. We obtained responses from 253 

transportation planning organizations (74 percent) and 45 state air quality 

agencies (86 percent). See appendixes I, II, and III for more details on our 

scope and methodology and for the results of each survey. We conducted 

our review from August 2002 through April 2003 in accordance with 

generally accepted government auditing standards. 

Over the past 6 years, 56 of the 159 transportation planning areas with air 

quality problems (35 percent) have experienced at least one conformity 

lapse, although few had to change their transportation plans to resolve the 

lapse. Areas lapsed in 26 cases because transportation planners lacked the 

time and resources to complete the conformity process by the required 

deadlines, or because they experienced administrative or technical 

problems. Areas lapsed in 18 cases because they had difficulty designing a 

transportation plan that would control future emissions enough to meet 

their budget, but in 6 of these cases, the difficulty was with the 

requirements of the conformity process itself and not with the amount of 

emissions that would be generated by the projects in their plan. In the 

remaining cases, areas lapsed for a variety of other reasons, such as not 

having an EPA-approved state air quality plan with an emissions budget in 

time for the conformity demonstration. While some took longer, about 65 

percent of all lapses took 6 months or less to correct. Most areas 

Results in Brief 
Page 4 GAO-03-581 Environmental Protection 

addressed their lapse by correcting administrative or technical issues, or 

taking the needed time to catch up with their workload and complete the 

conformity process. Another 11 areas recalculated the emissions budget to 

resolve the lapse, and only 5 areas needed to revise their transportation 

plans. About one-third of the 253 transportation planners nationwide 

responding to our survey anticipate having difficulty demonstrating 

conformity in the future, however, especially under the new air quality 

standards for ozone and particulate matter. For example, EPA estimates 

that about 50 areas of the country that will not meet the revised standards 

will have to demonstrate conformity for the first time. EPA and DOT have 

taken some preliminary steps to help prepare these new areas, but some 

are concerned, for example, about having the resources and staff with the 

necessary technical skills to complete the conformity process. 

About two-thirds of the 118 transportation planners responding to our 

survey who currently demonstrate conformity reported that the frequency 

with which they must do so limits the time and funds available to address 

other important transportation challenges, such as alleviating congestion 

and ensuring highway safety. All three of the proposed changes to the 

transportation planning process that stakeholders have offered could 

result in less frequent conformity demonstrations, addressing the planners’ 

concerns. Nearly three-quarters of the transportation planners favored 

extending the frequency between updates of the long-range plan and most 

preferred at least once every 5 years, rather than once every 3 years as 

currently required for areas with air quality problems. If the requirement to 

demonstrate conformity of the plan were also revised accordingly, this 

could result in less frequent demonstrations. Forty-five percent of the 

planners favored extending the frequency between updates of the TIP, and 

30 percent favored combining the plan and TIP into a single document.2

 

Seventeen state air quality planners responding to our survey also 

supported the most favored proposal to extend updates of the plan. But 

when asked if the proposal could jeopardize their ability to meet air 

quality standards, 16 air quality planners said they thought that it could. 

However, in responding to this question, the air quality planners were not 

asked to take into account the fact that the transportation planners would 

still be demonstrating conformity of their TIPs every 2 years. As EPA 

program managers also noted, any time transportation planners add a 

project to their TIP that was not in the plan, they would have to 

 2

 Thirty-one percent of survey respondents neither favored nor opposed, or are unsure at 

this time, about combining the plan and TIP. 
Page 5 GAO-03-581 Environmental Protection 

demonstrate conformity on both the TIP and plan. Furthermore, 

transportation planners could, as needed, update their long-range plan and 

associated conformity demonstration more frequently than required. In 

fact, a number of transportation planners reported that they have done 

this in order to add new projects, shift funds among projects, or make 

other changes. All of these factors would help to ensure that adopting the 

proposal to extend the frequency of updates to the long-term plan would 

not have a significant impact on the conformity process and its role in air 

quality protection. Because there are advantages to be gained from freeing 

up transportation planners’ time and resources and ways to mitigate 

potential disadvantages, we are recommending that DOT, in coordination 

with EPA, consider (1) revising its regulations to extend the current 3-year 

time frame between required updates of the long-range transportation 

plan, and (2) submitting a legislative proposal to revise the conformity 

provisions of the Clean Air Act so that they similarly extend the time frame 

between required conformity demonstrations for the plan. 

Transportation planners responding to our survey who experienced a 

lapse or difficulty demonstrating conformity identified a second issue that 

none of the three proposals in our study addresses, one that stems from a 

difference between requiring updated transportation plans and TIPs but 

not air quality plans and emissions budgets. Currently, transportation 

planners must update their plans and TIPs and demonstrate conformity on 

a regular basis. In doing so, they must use such factors as the most current 

data on the size of the area’s population and the number and types of 

vehicles in use. The planners must also input this data into the most 

current version of the model that estimates future emissions from their 

planned transportation projects. State air quality planners, on the other 

hand, are not required to periodically update their plans and vehicle 

emissions budgets to reflect the more current data and model.3

 As a result, 

if the more current factors or model indicate a larger than expected 

increase in future emissions, the transportation planners must further 

revise the projects they include in their plans and TIPs until they can offset 

all of the additional increase and stay within the vehicle emissions budget. 

Such revisions could cause some areas to delay projects, such as building 

a new road, while other areas may not have that option and instead have 

 3

 In certain areas, state air agencies must conduct an inventory of emissions every 3 years, 

but are not required to update their plans based on these data, even if the inventory shows 

an increase in emissions. Some of these areas must use the data to demonstrate to EPA 

that they are making the necessary progress in achieving air quality standards, and if not, 

they may have to revise their plans accordingly. 
Page 6 GAO-03-581 Environmental Protection 

to rely on adding a number of projects to the plans and TIPs intended to 

reduce emissions. If states periodically updated their air quality plans to 

incorporate the most current data and model, they could reassess whether 

these types of transportation changes were best for an area, or whether 

they have achieved enough, or more cost-effective, reductions from other 

sources so that they could revise the vehicle emissions budgets and 

provide transportation planners some flexibility. Twelve of 45 air quality 

planners responding to our survey reported that they updated air quality 

plans and increased the emissions budget or built a safety margin into it, 

allowing transportation planners to be able to demonstrate conformity. In 

addition, 13 others reported that they would consider updating their plans. 

Conducting these updates, as with conducting transportation plan 

updates, can be challenging, time-consuming, and costly, however, 

according to 32 of the air quality planners and EPA program managers. For 

example, the air quality planners would have to solicit agreement on 

allowable emissions levels from all sources, stakeholders, and the public, 

and running the required photochemical model could take as long as 3 

years in larger metropolitan areas with many sources of air pollution. 

Recognizing that updating air quality plans could be costly for some areas, 

we recommend that EPA, in coordination with DOT, more 

comprehensively assess the potential disadvantages of such updates and 

the likely extent that anticipated benefits would be achieved by 

establishing a Clean Air Act requirement to regularly update state air 

quality plans with the most current data and models. 

We provided DOT and EPA with a draft of this report for their review and 

comment. Both agencies provided technical comments that we 

incorporated into the report as appropriate. DOT generally agreed with 

our conclusions and recommendations and said that the report was timely 

and highlighted issues that needed to be addressed. EPA generally agreed 

with our conclusions and recommendations for changes to the 

transportation planning process and the associated requirements to 

demonstrate conformity, but wanted to consult with the states before 

agreeing with our recommendation that the agency comprehensively 

assess the advantages and disadvantages of establishing a requirement to 

periodically update state air quality plans. 

The Clean Air Act requires EPA to establish air quality standards to protect 

public health and the environment. These standards—known as the Background 
Page 7 GAO-03-581 Environmental Protection 

“national ambient air quality standards”—establish health and 

environmentally-based limits on the amount of six criteria pollutants that 

are allowed in the air.4

 States must develop state implementation plans 

(SIP) for implementing, maintaining, and enforcing the standards.5

 When 

the level of any of these pollutants exceeds the standard in an area of the 

country, EPA may designate that area as being in nonattainment of the 

standard. Once the standard is attained, EPA redesignates the area as 

being in attainment, but the state must submit revisions to its state air 

quality plan demonstrating how it will maintain this level of air quality for 

20 more years.6

 The following map illustrates the counties of the nation 

currently in nonattainment or maintenance for at least one of the six 

criteria pollutants. 

 4

 The six criteria pollutants are ozone, particulate matter, carbon monoxide, lead, nitrogen 

dioxide, and sulfur dioxide. 

5

 In some cases, localities within a state may also develop air quality plans. 

6

 According to DOT conformity program managers, states are to submit these maintenance 

plans in two 10-year increments, in part because it is difficult to make projections 20 years 

into the future with some certainty. 
Page 8 GAO-03-581 Environmental Protection 

Figure 1: Counties in Nonattainment or Maintenance Status for at Least One Criteria Pollutant 

Note: If a county was designated both nonattainment and maintenance for different pollutants, they 

will appear on this map as being in nonattainment. 

The Clean Air Act requires states to develop the SIP. To begin, state air 

quality planners must estimate the emissions from mobile, point, and area 

sources. The air quality planners are then required to establish emissions 

goals for each of these sources and design cost-effective and feasible 

strategies that will result in progress towards attaining, or maintaining, the 

air quality standards. For on-road mobile sources, the emissions goal is 

known as a motor vehicle emissions budget. The total amount of 

emissions that can come from on-road mobile sources, such as cars, 

motorcycles, and trucks, as well as transit vehicles that include buses, 

cannot exceed this budget. EPA is responsible for approving the state’s 

initial air quality plan and any subsequent revisions to it. Although states 
Page 9 GAO-03-581 Environmental Protection 

are not required to regularly update their plans for attaining or maintaining 

the standards, they are required to update them at certain times, such as 

when EPA revises an air quality standard or the area’s designation 

changes. 

Transportation planners also play a key role in making sure areas meet 

their emissions budget. Local planning agencies are responsible for 

carrying out the transportation planning process in a metropolitan or 

urbanized area.7

 As part of this process, these agencies are to develop 

transportation plans and transportation improvement programs (TIP). A 

transportation plan specifies a long-range, 20-year vision for a 

metropolitan area’s transportation system. DOT regulations require that 

for nonattainment and maintenance areas, their plans be updated at least 

once every 3 years and attainment areas at least once every 5 years. In 

contrast, the TIP is a short-range, more detailed document that specifies 

the priority projects to be implemented in the next 3 years. Federal 

transportation laws specify that all areas must update the TIP at least once 

every 2 years. In developing the plan and TIP, the transportation planners 

must consult with state and federal transportation and environmental 

agencies, as well as the public. The purpose of this consultative 

requirement is to ensure that all agencies meet regularly and share 

information on changes to the area’s future network that will preserve air 

quality. 

Transportation planners rely on three types of information, among other 

things, in developing their transportation plan and TIP: (1) the future size 

of an area’s population and where the people will live and work, (2) how 

these people will travel, and (3) what kind of transportation network is 

and will be in place to meet travel needs. The planners predict future 

travel most often by inputting this information into a model that forecasts 

future travel demand, such as how many cars will be on a particular road 

at a certain time. The planners determine the mix of transportation 

projects they will propose in the plan and TIP to meet this demand. 

Planners in nonattainment or maintenance areas for ozone, carbon 

monoxide, particulate matter, or nitrogen dioxide must meet additional 

requirements. While all planners must estimate future travel needs, 

planners in nonattainment and maintenance areas must more precisely 

 7

 The Federal-Aid Highway Act of 1973 authorized the use of federal funding for local 

planning agencies—known as metropolitan planning organizations—in areas with 

populations of 50,000 or more to carry out planning at the metropolitan level. There are 

currently 341 metropolitan planning organizations in the United States and Puerto Rico. 
Page 10 GAO-03-581 Environmental Protection 

calculate the number of vehicle miles people will travel under the plan and 

TIP, and, among other things, input this information into another model 

that estimates the emissions their transportation plans will generate. 

Figure 2 outlines this travel forecasting process. 

Figure 2: Process for Forecasting Future Travel Demand 

Note: In some cases, if conformity cannot be demonstrated, air quality plans and emissions budgets, 

rather than transportation plans, may be revised accordingly. 
Page 11 GAO-03-581 Environmental Protection 

Under the Clean Air Act, transportation planners in nonattainment or 

maintenance areas must demonstrate that the estimated emissions 

generated through this process will not exceed the area’s emissions 

budget, a process known as “demonstrating conformity.” Planners must 

make this comparison at least once every 3 years, if they update either the 

plan or TIP, or if states make certain changes to air quality plans. The 

transportation planners must submit the results of this demonstration to 

DOT, which reviews them, determines whether the area complies with the 

requirements, and makes an independent conformity determination, in 

consultation with EPA. If either the plan or TIP does not conform to the 

emissions budget by a specified deadline, or if the plan or TIP expires 

before a new one is adopted, the area enters into what is known as a 

“conformity lapse.” In this case, the transportation planners can only 

spend federal transportation funds on certain projects, such as safety, 

mass transit, and air quality projects, until it resolves the problem and can 

demonstrate conformity. 

In 2004, EPA plans on designating nonattainment areas under two new, 

more stringent air quality standards for ozone and fine particulate matter 

in order to be more protective of public health. The current ozone 

standard limits the concentration of ozone allowed in the air over a 1-hour 

period of time. The revised standard is more stringent and is averaged over 

an 8-hour period. EPA revised the standard because it is now known that 

chronic exposure to the pollutant is a health concern. The new fine 

particulate matter standard is also more stringent and covers smaller size 

particles found in vehicle emissions, among other sources, which can be 

more deeply inhaled, making them more likely to contribute to health 

problems. Areas that EPA designates as not meeting either standard will 

be subject to the conformity process 1 year after the effective date of this 

designation. 

The Congress has taken an interest in reviewing these requirements as it 

attempts to reauthorize the nation’s surface transportation programs. To 

help the Congress in its efforts, we first reported on the conformity 

process and other transportation-related air quality programs and issues in 

an October 2001 report, and in a statement for a congressional hearing 
Page 12 GAO-03-581 Environmental Protection 

conducted in July 2002.8 A number of other stakeholders, such as research 

organizations, industry associations, and environmental organizations, 

have also issued reports or proposed changes related to transportation 

planning and conformity as part of the TEA-21 reauthorization debate. For 

example, Resources for the Future recently released a report examining 

how conformity is affected by the transportation and air quality planning 

processes.9

 In addition, Harvard University’s Taubman Center for State and 

Local Government issued a report discussing challenges that areas will 

face in implementing the new standards, including requirements to 

demonstrate conformity.10 Furthermore, industry groups, including the 

Association of Metropolitan Planning Organizations; the State and 

Territorial Air Pollution Program Administrators and the Association of 

Local Air Pollution Control Officials; the American Association of State 

Highway and Transportation Officials; and Environmental Defense have 

also developed positions on transportation planning, conformity, or both. 

We were asked to review three proposals that could directly impact the 

conformity requirements outlined in the Clean Air Act: (1) extending the 

time between required updates of the long-range transportation plan, (2) 

extending the time between required updates of the TIP, and (3) 

combining these two documents into one. All three proposals would result 

in extended time frames between conformity demonstrations. While we 

recognize that other changes have been proposed that would impact the 

conformity requirements, we did not include them in our review because 

other organizations are either studying them or have recently issued 

reports that discuss them. For example, transportation planners have 

raised concerns about having to use the latest version of the model to 

estimate future emissions, the MOBILE6 model, and the impacts the model 

will have on their estimates. DOT and EPA have a number of modeling 

 8

 U.S. General Accounting Office, Environmental Protection: Federal Incentives Could 

Help Promote Land Use That Protects Air and Water Quality, GAO-02-12 (Washington, 

D.C.: Oct. 31, 2001; and Environmental Protection: The Federal Government Could Help 

Communities Better Plan for Transportation That Protects Air Quality, GAO-02-988T

(Washington, D.C.: July 30, 2002). 

9

 Winston Harrington, Arnold Howitt, Alan J. Krupnick, Jonathan Makler, Peter Nelson, and 

Sarah J. Siwek, “Exhausting Options: Assessing SIP-Conformity Interactions,” RFF Report, 

January 2003. 

10 Jonathan Makler and Arnold M. Howitt, “Regulating Transportation in New 

Nonattainment Areas Under the Eight-Hour Ozone Standard,” Taubman Center for State 

and Local Government, Presented at the 82nd Annual Meeting of the Transportation 

Research Board, Washington, D.C., January 12-16, 2003. 
Page 13 GAO-03-581 Environmental Protection 

initiatives underway, such as training, to help address these concerns. In 

addition, some planners have raised concerns because they have to 

estimate emissions and demonstrate conformity over the entire 20-year 

horizon of the long-range transportation plan, while air quality planners 

typically only have to project emissions and set a budget for the period 

until their attainment date, which is a shorter period of time. The 

Resources for the Future study referred to above assessed the impact of 

these differing requirements and ways to address problems they 

presented. 

Few areas that experienced a conformity lapse since 1997 had to revise or 

change their transportation plans in order to resolve the problem. Instead, 

in order to end the lapse, most of these areas needed to resolve 

administrative and technical problems or take additional time to complete 

the conformity process. However, more than one-third of the 

transportation planners responding to our survey reported that they 

expected their areas to have difficulty demonstrating conformity in the 

future. For example, a number of areas will be subject to EPA’s new, more 

stringent air quality standards for ozone and fine particulate matter and 

will have to demonstrate conformity for the first time, posing challenges 

for some areas. 

Over the past 6 years, 56 (35 percent) of the 159 transportation planning 

areas with air quality problems had at least 1 conformity lapse, according 

to EPA and DOT data.11 Thirty-nine (65 percent) of these lapses lasted 6 

months or less. Figure 3 shows the length of conformity lapses from 1997 

through 2002. 

 11 Since 1997, 56 areas experienced a total of 60 conformity lapses. Four areas had more 

than one conformity lapse during this period. 

Few Areas Have 

Needed to Change 

Transportation Plans 

to Resolve a 

Conformity Lapse, but 

More May Need to Do 

So in the Future to 

Meet New Standards 

One-Third of Areas Had 

Conformity Lapses but 

Most Were 6 Months or 

Less 
Page 14 GAO-03-581 Environmental Protection 

Figure 3: Length of Conformity Lapses, 1997-2002 

Lapses ranged from 4 days to just over 4 years, with the median lapse 

lasting approximately 4 months. Nine conformity lapses lasted a year or 

more, but EPA conformity program managers explained that most of these 

areas did not have pending new projects and, therefore, were not under 

time pressures to resolve their lapse. During the lapses, areas did not lose 

their federal transportation funds permanently; rather, federal funds were 

restricted to certain projects, such as safety, mass transit, and air quality 

projects, until the lapses were resolved. The data the agencies provided 

did not include information on the impacts that the lapses may have had 

on new transportation projects, but, according to the DOT conformity 

program manager, even short lapses can be disruptive to the 

transportation planning process. For example, in some states, a short 

lapse could delay the start of a project until the next construction season. 

Twenty-six of the conformity lapses that occurred since 1997 were caused 

by areas’ transportation planners lacking time and resources (8 lapses) to 

complete the conformity process by the established deadlines, or 

experiencing administrative or technical problems (18 lapses). For 

example, planners in eight of these areas indicated that they simply did not 

have enough time to complete the transportation planning and conformity 

processes. Several planners stated that they missed deadlines because 

their area’s transportation planning organization did not have enough staff. 

Most Conformity Lapses 

Were Caused by Resource, 

Administrative, or 

Technical Problems Rather 

than Difficulties Meeting 

Emissions Budgets 
Page 15 GAO-03-581 Environmental Protection 

One of these planners noted that even though their organization had a 

relatively small staff, they had to complete all the same steps in the 

process as planning organizations with many more staff, such as the timeconsuming step of coordinating the plan among all relevant stakeholders 

and the general public. Common administrative problems planners faced 

included misunderstandings as to when deadlines occurred, confusion 

about the specific requirements in the process, or delays at the federal 

level in processing required paperwork. Technical problems included 

difficulties related to the data needed to complete the process, such as the 

types of vehicles in use, or the model that estimates emissions from 

transportation plans and projects. Figure 4 shows the primary causes of 

conformity lapses. 

Figure 4: Primary Causes of Conformity Lapses, 1997-2002 

Another 18 lapses resulted from areas experiencing difficulties in 

designing a transportation plan that achieved sufficient emissions 

reductions to meet the budget. However, in 6 of these cases, the difficulty 

was with the conformity requirements and not with the amount of 

emissions expected from the proposed transportation projects. For 

example, some areas had more current data on the types of vehicles in use 

that they had to incorporate into their most recent demonstration. Even 
Page 16 GAO-03-581 Environmental Protection 

though the planners did not change the mix of transportation projects in 

their plan, the use of the new data resulted in a higher estimate of 

emissions from the plan. In addition, areas must demonstrate that all 20 

years of their long-term transportation plan will conform to the emissions 

budget. However, states typically only set a budget for 10 years or less, 

although in a few cases, states established budgets over a longer time 

period, according to EPA program managers. As a result, transportation 

planners generally must restrict emissions in each of the final 10 years of 

the transportation plan to the amount that is set in the 10th year of the 

emissions budget. This can pose problems because some areas are likely 

to experience growth that could increase emissions in these later years. 

Since the emissions budget does not cover these years, it does not account 

for this growth. Therefore, areas may have to be more restrictive than 

necessary in the types of projects they include in the later years of their 

plans. 

Finally, in six cases, planners in these areas experienced difficulties 

meeting certain additional federal planning requirements. These included 

DOT’s requirement that planners prove their area will have sufficient funds 

to cover the projects in its TIP, and EPA’s requirement that a state’s air 

quality plan and emissions budget be approved or found to be adequate 

before it can be used for a conformity demonstration. In the remaining 10 

cases, the EPA and DOT data did not provide the reasons why areas 

missed the conformity deadlines. 

Areas used a range of activities to resolve their conformity lapses, 

according to the data EPA and DOT provided. For example, the 8 areas 

that lapsed as a result of insufficient time or staff resources were able to 

take the extra time to complete the process. Those 18 areas that 

experienced administrative or technical difficulties also resolved them by 

taking more time, making a technical change, using some other solution, 

or a combination of activities. Overall, we found that in 16 cases, areas 

used some administrative or technical solution to resolve the lapse, while 

in another 16 cases, areas took the additional time needed to catch up with 

their schedules or workload. For example, in 7 of the 16 cases where areas 

used an administrative or technical solution, areas had to apply the correct 

model or other methodology to their conformity demonstration. Several of 

these areas had to use updated versions of the model that predicts vehicle 

emissions, or to update or correct other calculations in the conformity 

analysis, such as projections of the number of miles people typically drive. 

In 5 of the 16 cases, lapses were resolved through administrative actions, 

such as federal agencies correcting delays in reviewing the required 

Most Areas Needed to 

Take More Time or Make 

Technical Corrections to 

Their Conformity 

Demonstration to Resolve 

Their Lapses 
Page 17 GAO-03-581 Environmental Protection 

paperwork to demonstrate conformity. Figure 5 shows the primary 

solutions used to resolve their lapses. 

Figure 5: Primary Solutions to Conformity Lapses, 1997-2002 

Another 16 lapses were resolved through more substantive steps, such as 

recalculating emissions budgets (11) or revising transportation plans (5). 

In most of the 11 cases, the states revised their air quality plans to reflect 

recalculated emissions budgets or to reflect strategies, such as the 

introduction of more stringent emissions tests for cars or tighter controls 

on emissions from industry and other sources, to reduce emissions. In the 

5 cases, areas revised their TIP or long-range transportation plan to 

achieve the necessary emissions reductions to demonstrate conformity. 

For example, areas added mass transit projects to their plans because they 

produce relatively lower emissions. Similarly, areas may have resolved a 

lapse by taking credit for adding emissions-reducing programs to their 

plan that they will implement in the future, such as the heavy-duty diesel 
Page 18 GAO-03-581 Environmental Protection 

rule designed to reduce the sulfur content of diesel fuel, a critical 

component of provisions for reducing tailpipe emissions from heavy-duty 

diesel engines. 

While most areas have been able to demonstrate conformity or resolve a 

lapse through some administrative or technical action, some areas may 

have difficulty demonstrating conformity in the future. Of the 253 

transportation planners nationwide responding to our survey, 91 (36 

percent) reported anticipating having such difficulty in the future and, of 

these, 80 anticipated difficulty when EPA introduces the two new, more 

stringent air quality standards. Another 52 respondents (21 percent) did 

not know whether they would have difficulty demonstrating conformity in 

the future. 

Of the 91 planners who anticipate having difficulty, 59 work in areas that 

already have air quality problems or had them in the past, and 32 work in 

areas that have not had problems. These 32 planners will have to 

demonstrate conformity for the first time if any county within their 

jurisdiction is designated as being in nonattainment for either of the 

standards. Using the most recent EPA air quality monitoring data, we 

estimated that 88 counties currently meeting the 1-hour standard will not 

meet the 8-hour standard. Figure 6 illustrates the counties that will not 

meet the new ozone standard for the first time. 

Some Areas May Have 

Difficulty Demonstrating 

Conformity in the Future, 

Especially under the New 

Air Quality Standards 
Page 19 GAO-03-581 Environmental Protection 

Figure 6: Counties Expected to Violate the New Ozone Standard for the First Time 

This estimate may be understated because EPA’s data are based on data 

received only from those counties that have an ozone monitor showing a 

violation of the standards. However, a number of other counties do not 

have monitors or data on air quality. In these cases, the state governor or 

EPA can still designate such counties as not meeting the standard. For 

example, if the county without data is contiguous to a county with data 

that show it violates the standard, the governor can recommend that EPA 

designate the contiguous county as also not meeting the standard because 

it contributes to a violation in another county, or EPA can independently 

decide to make this designation. 
Page 20 GAO-03-581 Environmental Protection 

According to an EPA conformity program manager, the agency has done a 

preliminary analysis of the counties with data that show they will violate 

either of the new standards, as well as contiguous counties that might be 

designated as being in nonattainment. Using this information, EPA has 

grouped counties into potential areas that would be subject to conformity 

under either of the new standards. EPA estimates that about 150 areas will 

be subject to conformity and that 50 of them will be demonstrating 

conformity for the first time. 

Several transportation planners volunteered to provide additional details 

on why they were concerned about demonstrating conformity in the 

future. Their concerns included not having the trained staff or funds to 

complete the process. For example, one planner said the new standards 

will require that more time and attention be given to the transportation 

plans in order to demonstrate conformity, which will be burdensome and 

difficult for local transportation planning agencies that have a small 

number of staff. A DOT conformity program manager pointed out that in 

addition to demonstrating conformity for the first time, these new areas 

will now have to update their long-term plans every 3 years instead of 5 to 

comply with current requirements, increasing the demand on staff and 

resources. The program manager added that besides being resource 

intensive, demonstrating conformity is also very challenging. For example, 

the model used to estimate emissions is technically complex and some of 

the planners, as well as other key stakeholders, expressed concerns about 

whether the local planning organizations would have staff with the 

requisite skills to run the model. Another planner, as well as a key 

stakeholder, pointed out that while state transportation organizations 

currently run the model for some local planners, the state organizations 

might not have the staff or funds to manage an additional workload in the 

future. In addition, while state organizations receive federal funds to 

support local transportation planning activities, as more local planners 

have to demonstrate conformity and need resources to do so, the state 

agencies will have to spread these funds to a greater number of planners. 

Furthermore, as our analysis of the causes of conformity lapses shows, 

some transportation planners who had to demonstrate conformity to date 

had difficulty understanding all of the conformity requirements or lacked 

time to complete them, thus planners who will be demonstrating 

conformity for the first time could also face these problems. 

EPA and DOT have recognized that new areas may need help in 

demonstrating conformity and have taken some action to provide it. For 

example, areas will have a 1-year grace period after EPA formally 

designates them as not meeting either one of the standards before the 
Page 21 GAO-03-581 Environmental Protection 

transportation planners will have to demonstrate conformity. In addition, 

areas that meet the current ozone standard but that may violate the 

revised standard can enter into a compact with EPA. Under this Early 

Action Compact, an area can begin to take steps to control ozone now, and 

in exchange, EPA will defer the effective date of the nonattainment 

designation of the area, thereby postponing the requirement to 

demonstrate conformity. DOT conformity program managers noted that 

such compacts do not apply to areas that may be designated as being in 

nonattainment for the fine particulate matter standard. Furthermore, (1) 

DOT offered training courses on conformity and both agencies offered 

training on the latest version of the emissions model, (2) the agencies are 

developing several new courses, (3) they have entered into a cooperative 

agreement with the National Association of Regional Councils (NARC)—

an association whose members include transportation planners—to 

provide some training to members, and (4) DOT has established a Web site 

for planners to exchange information on conformity issues. Finally, as 

EPA program managers pointed out, since some of the areas that will have 

to demonstrate conformity for the first time are contiguous to other areas 

that have already had to demonstrate conformity, transportation planners 

may already be experienced in the conformity process or, if not, can get 

help from other planners in the state. The agencies’ actions to date, 

however, do not address planners’ concerns about having enough 

resources or staff with the necessary technical skills to successfully 

demonstrate conformity. 

Most of the planners who have to demonstrate conformity said the 

frequency under the current requirements limits the time and funds 

available to address other transportation challenges. A proposed change to 

the transportation planning process, which most of the planners favor, 

would reduce the frequency of conformity demonstrations, thereby 

helping to address the problem transportation planners identified. They 

also identified a second problem with the conformity process—the 

difference between requirements to update transportation and air quality 

plans—that the proposed change does not address. This difference can 

result in transportation planners having to revise their transportation plans 

in ways that may not best serve the transportation needs of the area. 

Frequency of 

Demonstrating 

Conformity and 

Inconsistent 

Requirements for 

Updating 

Transportation and 

Air Quality Plans 

Cause Problems 
Page 22 GAO-03-581 Environmental Protection 

Transportation planners responding to our survey reported that updating 

their long-range plans as often as currently required does have certain 

advantages. One primary advantage they identified was that it gave them 

an incentive to work cooperatively with other agencies. Such cooperation 

for transportation planners that must demonstrate conformity can 

promote early and frequent coordination between transportation and air 

quality planners, helping to avoid last minute conformity problems and 

lapses. Furthermore, frequent updates can help focus public attention on 

transportation planning. For example, one transportation planner 

commented that updating the long-range plan helped provide the public 

with a greater understanding of the nature of air quality problems and why 

alternative modes of travel may be needed in the future. 

Given these advantages, nevertheless, 77 of the 118 (66 percent) 

transportation planners who have to demonstrate conformity when they 

update their long-range plan reported that the current frequency can limit 

the amount of time available to address other transportation-related 

challenges, such as relieving congestion and ensuring safety. In addition, 

79 of the 118 (69 percent) said that it strains staff resources. Some 

transportation planners expressed concern that once they complete a 

long-range plan update, and demonstrate conformity if required to do so, 

they are already behind in developing the next long-range plan. Some also 

said they have no time in between plan updates to think more strategically 

about future alternatives for their transportation network, build their 

modeling and other technical skills, or obtain better information for their 

planning process, such as congestion levels on certain roads. 

The three proposals to change the transportation planning process that we 

reviewed could also result in less frequent conformity demonstrations, 

which would, in turn, address the planners’ concerns. However, the 

majority of transportation planners responding to our survey favored only 

one of the proposals—reducing the frequency of required updates to the 

long-range transportation plan. Seventy-four percent (186) of the 253 

transportation planners responding to our survey would be in favor of less 

frequent plan updates, most preferring that these updates be performed at 

least every 5 years. This could result in less frequent conformity 

demonstrations for some areas. Besides freeing up time and staff 

resources, another reason planners supported the change was that 

planning factors, such as travel behavior and the transportation projects 

already underway, do not change enough to justify the time and expense 

of revising the plan every 3 years. In addition, they also responded that 

extending the update cycle may provide more time to better coordinate 

their plans and projects with other agencies and stakeholders, such as 

Planners Said Current 

Frequency of 

Demonstrating Conformity 

Strains Time and 

Resources but Support a 

Proposed Change That 

Could Reduce This Burden 
Page 23 GAO-03-581 Environmental Protection 

local land use agencies that guide an area’s future growth and 

development. 

Planners were less supportive of the two other proposals to change the 

transportation planning process that could also reduce the frequency of 

conformity demonstrations—reducing the frequency of required updates 

to the TIP and combining the TIP and plan into a single document. 

Although planners recognize that both proposals would have benefits, they 

noted that the changes would eliminate some advantages of the current 

requirement. While 45 percent (113) of the planners supported reducing 

the frequency of required updates to the TIP, a majority of the planners 

who did not support the change reported that frequent updates of the TIP 

allowed areas to add new projects that had not been part of the prior TIP 

because funding priorities changed in the meantime. According to the 

DOT conformity program managers, reducing the frequency of required 

updates to the TIP does not preclude transportation planners from 

conducting the updates more frequently. 

Thirty-nine percent of the 253 planners responding to the survey did not 

favor combining the TIP and plan. Some of these planners felt that the two 

documents serve very distinct functions. For example, they believe the TIP 

allows them to more easily respond to changing needs. Therefore, some 

planners expressed concern that combining the two documents could 

undermine the effectiveness of both plans. On the other hand, 30 percent 

favored the change, stating that the TIP is really a subset of the plan and 

having to demonstrate conformity on both plans is unnecessarily 

redundant. (An additional 31 percent neither favored nor opposed the 

change or were unsure of their position.) 

Seventeen of the 45 state air quality planners responding to our survey 

also supported reducing the frequency of updates to the long-range plan 

(12 did not support the change and 16 were unsure or had no opinion). 

When asked what effect the change would have on their state’s ability to 

meet air quality standards, 16 said it would have a negative effect and 5 

said it would have a positive effect (of the remaining planners, most said it 

would have no effect or they had no basis to judge its effect). Some of the 

air quality planners mentioned that the transportation network in high 

growth areas could generate increased travel, resulting in higher 

emissions. They suggested that these areas might warrant more frequent 

updates to the long-range plan than the proposal would provide to ensure 

that air quality goals are being met. 
Page 24 GAO-03-581 Environmental Protection 

The air quality planners who thought the change could have a negative 

effect, however, were not asked to take into consideration the fact that the 

transportation planners will still be required to demonstrate conformity of 

their TIPs at least every 2 years when they are updated. In addition, EPA 

program managers also noted that if planners want to include a new 

project in their TIP that is not in their 20-year plan, they must demonstrate 

conformity on both the TIP and plan. Furthermore, as our survey showed, 

transportation planners could still choose to update their long-range plans 

more frequently than once every 5 years, at which time they would be 

required to demonstrate conformity. In fact, 58 (23 percent) of planners 

responded that they update their long-range plans more frequently than 

currently required, primarily to add new projects that are needed to 

address the area’s changing transportation needs. All of these factors 

would help to preserve the role that conformity plays in protecting air 

quality, even under the proposed change. Because the proposal to extend 

the frequency of updates to the long-range plan—and, therefore, the 

frequency of conformity demonstrations—addresses the primary problem 

transportation planners have with the conformity process, and the 

proposal’s potential effects on air quality protection could be limited, 

modifying conformity regulations and the Clean Air Act in this manner 

may be feasible. 

Those transportation planners who experienced a lapse or said they had 

trouble demonstrating conformity in the past identified a second issue 

with the conformity process that stems from the difference between the 

update requirements for the transportation and air quality plans. State air 

quality planners are not required to regularly update their plans, even 

though an area may have experienced population growth and a sometimes 

unexpected increase in the types of certain vehicles in use, which in turn 

can result in an increase in emissions. States with areas in nonattainment 

for ozone and carbon monoxide are required to take an inventory of the 

emissions being generated by each of the major sources every 3 years, but 

are not generally required to update their air quality plans to reflect this 

data. Consequently, the state air quality planners do not regularly reassess 

to what extent they should revise the vehicle emissions budgets for 

transportation, or add other measures to reduce emissions from mobile 

sources to the plan, to offset this increase given their ability to reduce 

emissions from industrial or area sources where possible. Transportation 

planners, on the other hand, are required to update their TIP and plan on a 

regular basis—at least every 2 or 3 years respectively for areas in 

nonattainment or maintenance and every 2 or 5 years for areas in 

attainment of the standards. With each of these updates, planners are 

Requiring Updates to 

Transportation Plans but 

Not Air Quality Plans 

Makes It Difficult to 

Demonstrate Conformity 

in Some Areas 
Page 25 GAO-03-581 Environmental Protection 

required to use the most current model that estimates the vehicle 

emissions generated by their plans. They must also use the most current 

information on factors that are inputs to the model, such as population 

and the number and types of vehicles in use, so that they can more 

realistically determine whether their plans and TIPs are consistent with 

the emissions budget, according to EPA conformity program managers. 

When this model and data indicate an increase in emissions, the 

transportation planners must address it. 

In the absence of an updated air quality plan, transportation planners must 

generally try to offset all of the extra emissions from transportation 

activities by revising their plan or TIP so that they do not have a 

conformity lapse. However, transportation planners may be limited in the 

ways in which they can make changes that reduce emissions enough to 

meet the vehicle emissions budget and demonstrate conformity. For 

example, one possible change is to remove projects that modeling 

estimates may increase emissions in an area, such as a highway or road 

expansion project, or to add measures, such as increasing the size of the 

bus fleet that uses diesel engines. However, such projects were most likely 

added to address other transportation challenges, such as reducing 

congestion or better linking existing road networks. Furthermore, as one 

transportation planner explained, planners in some areas may have few 

projects to eliminate because the transportation network is already 

developed. 

Rather than eliminate projects, transportation planners can also try to add 

certain emissions control strategies to their TIP or plan. These include 

bicycle or pedestrian facilities or expanded transit options to discourage 

the use of vehicles. Other strategies include synchronized traffic lights to 

reduce idling vehicles, the conversion of public buses to cleaner burning 

fuels, and the retrofitting of certain vehicles with cleaner engines. EPA 

program managers also pointed out that transportation planners can 

estimate the emissions reductions that will be achieved by new programs 

they will implement but that are not yet in air quality plans, such as new 

emissions standards for light-duty trucks. The planners can take credit for 

the emissions reductions from such programs in order to demonstrate 

conformity. However, these strategies may provide relatively small 

emissions reductions. 

For example, the Washington, D.C., region recently had difficulty 

demonstrating conformity, in part because many more drivers than 

anticipated were using higher-polluting sport-utility vehicles. Because 

transportation planning staff were updating the TIP and plan, they had to 
Page 26 GAO-03-581 Environmental Protection 

use this new data on vehicle use in their conformity demonstration, even 

though the emissions budget that they had to meet was based on the older 

data. The new data caused a significant yet unanticipated increase in the 

emissions estimates for the area that the staff had to offset in order to 

meet these outdated budgets. They delayed plans to build 100 miles of new 

roads, but this did not create enough of a reduction. Therefore, they had to 

add a number of emission control measures, such as park and ride lots, 

shuttle bus services, and bicycle and pedestrian facilities at rail stations, 

however these measures may achieve relatively small emissions 

reductions. 

The transportation planner in the Washington, D.C., region explained that 

if the air quality planners were required to update their plans periodically, 

account for the new model and data, and revise the emissions budgets, the 

transportation planners might be able to demonstrate conformity without 

cutting needed projects or adding costly control measures that achieve 

little emissions reductions. If states were required to periodically update 

their air quality plan, they would be required to reassess whether they had 

achieved or could achieve more cost-effective ways to reduce emissions in 

order to provide transportation planners with revised emissions budgets. 

For example, 12 of the 45 air quality planners responding to our survey 

said they had revised their air quality plan to update emissions budgets 

used to demonstrate conformity and 13 said they would consider doing so. 

Several planners that had updated their plan determined that the amount 

of projected emissions from all sources was less than the level needed to 

meet the standards, thus providing transportation planners a safety margin 

in the emissions budget. Such efforts can help an area compensate for 

unanticipated future growth or uncertainty in projected emissions. 

In 2003, some states that used an older version of the emissions model for 

their plan will have to update their air quality plan with the most recent 

version, which could temporarily address the differing requirements in 

these areas. In addition, according to EPA program managers, some areas 

are in the process of voluntarily revising their SIPs with the new model as 

well, and other areas that are designated as nonattainment for either of the 

two new standards will have to submit new plans to address these 

pollutants. Thirty-two of the 45 state air quality planners responding to our 

survey reported that revising their plans would be somewhat challenging. 

For example, with every update, air quality planners would have to obtain 

public input and involve many stakeholders with competing interests, 

especially those representing the other sources of pollution, including 

industrial (point) sources. The air quality planners would also have to use 

a complex photochemical model that estimates emissions from all 
Page 27 GAO-03-581 Environmental Protection 

sources, as well as the extent to which measures designed to control 

emissions achieve this result. According to air quality planners, running 

such a model requires a significant investment in resources and staff 

hours, and, according to one planner, can take as much as 3 years for a 

major metropolitan area with serious pollution problems to complete. 

Also, once a state revises its plan, EPA must review it and determine that it 

protects air quality before transportation planners can use the updated 

emissions budget to help them demonstrate conformity. Furthermore, 

according to EPA conformity program managers, some metropolitan areas 

will find they do not have the luxury of a safety margin to provide 

additional flexibility in their emissions budget. In considering whether to 

require updates of air quality plans to incorporate the most current data on 

travel patterns and emissions, as well as the most current emissions 

model, so as to resolve the difference with requirements to update 

transportation plans, stakeholders must weigh the potential benefits 

against the potential disadvantages. 

Overall, the conformity requirements of the Clean Air Act have helped to 

integrate transportation and air quality planning processes to better 

consider the emissions from the nation’s transportation systems and 

networks. In addition, few of the localities that have experienced a 

conformity lapse to date appear to have had to make major changes to 

their future transportation systems. Localities may have trouble 

demonstrating conformity in the future, however, if they cannot meet new 

air quality standards for ozone and fine particulate matter and may have to 

complete the conformity process for the first time. Both EPA and DOT 

have been working on guidance and training, among other things, to help 

the transportation planners in these areas, but some are concerned about 

having enough resources and staff with the necessary technical skills to 

successfully complete the conformity demonstration. 

While the conformity process has its advantages, most transportation 

planners who have to demonstrate conformity find that the frequency with 

which they have to do this robs them of staff and resources that could be 

used to solve transportation problems. Extending the 3-year time frame 

between updates to the long-term transportation plans—as well as 

amending the conformity requirements in the Clean Air Act to match—

would help to relieve some of this burden. Although some air quality 

planners fear this change would jeopardize their ability to meet clean air 

standards, this risk can be mitigated by several factors. For example, 

transportation planners will continue to demonstrate conformity when 

they update their TIPs or add new projects to the TIP that were not 

Conclusions 
Page 28 GAO-03-581 Environmental Protection 

previously in the plan. Also, a number of planners have already been 

updating their long-term plans more frequently than required and could 

continue to do so as needed under the change. 

Finally, some transportation planners have found it difficult to manage the 

conflict posed by the fact that they must frequently update their TIP and 

long-term plan—incorporating the most current data on an area’s 

population and travel patterns, as well as the most current version of the 

model that estimates emissions—while air quality planners do not. 

Establishing a requirement for air quality plans—and the vehicle emissions 

budgets they set for conformity—to be periodically updated with this new 

data and model could provide some benefits. These include incentives for 

areas to develop a more realistic emissions budget and to determine 

whether they could provide some flexibility in it so that transportation 

plans would not have to be restricted or modified in ways that may not be 

best for an area’s future. Some states updated their air quality plans and 

have experienced such benefits. Recognizing that compliance with such a 

requirement would be challenging and resource intensive for some states, 

however, emphasizes the need to more comprehensively assess the 

advantages and disadvantages of establishing such a requirement. One 

option to consider would be to establish a long enough time frame 

between required updates of the air quality plan as a way to limit the 

impact on resources. In addition, better synchronizing the time frame for 

air quality updates with the time frames established for transportation 

planning updates, and basing both on the same, most current data and 

models, would address the problems transportation planners identified 

with the differences in requirements. 

In order to make the conformity process a more effective and better link 

between air quality and transportation planning, we recommend the 

following to the Secretary of Transportation and the Administrator, EPA: 

• DOT, in coordination with EPA, should consider extending the current 

3-year time frame between required updates to the long-range 

transportation plan and submitting a legislative proposal to change the 

conformity provisions of the Clean Air Act so that they similarly extend 

the time frames between required conformity demonstrations for the 

plan. 

• EPA, in coordination with DOT, comprehensively assess the 

advantages and disadvantages of establishing a Clean Air Act 

requirement to periodically update state air quality plans so that they 

Recommendations for 

Executive Action 
Page 29 GAO-03-581 Environmental Protection 

incorporate the same, most current planning data and emissions 

models used in updates to the TIP and long-term transportation plans. 

We provided DOT and EPA with a draft of this report for review and 

comment. We subsequently met with or received comments from 

representatives of the following offices: 

• DOT’s Office of Natural and Human Environment within the Federal 

Highway Administration 

• DOT’s Office of Planning within the Federal Transit Administration 

• EPA’s Office of Transportation and Air Quality 

In general, DOT agreed with our conclusions and recommendations and 

said that the report was timely and highlighted issues that needed to be 

addressed. The DOT representatives said they would work with EPA to 

address our recommendation to consider extending the current 3-year 

time frame between required updates to the long-range transportation 

plan, and looked forward to working with EPA to assess the advantages 

and disadvantages of establishing a requirement to periodically update 

state air quality plans. DOT also suggested some technical changes 

throughout the report that we have incorporated as appropriate. In 

general, EPA agreed with our conclusions and recommendations for 

changes to the transportation planning process and the associated 

requirements to demonstrate conformity. However, EPA neither agreed 

nor disagreed with our recommendation that the agency comprehensively 

assess the advantages and disadvantages of establishing a requirement to 

periodically update state air quality plans. The EPA representatives said 

they believe the states already have the flexibility to decide whether new 

data or models justify the costs of conducting an update to the state air 

quality plan and that states are in a better position to make this decision. 

EPA also stated that they would want to discuss the issue with the states 

to understand their perspectives and how the states currently decide 

whether air quality plan updates are needed, before agreeing with the 

recommendation. However, as our survey data show, even though states 

have flexibility in deciding whether to update their plans, not all states 

would be willing to consider doing so. Furthermore, our survey data show 

that the current practice among the states has not resolved the problems 

the transportation planners reported experiencing as a result of the 

difference between requirements to update transportation plans but not 

air quality plans, given that this was one of the most significant problems 

Agency Comments 

and Our Evaluation 
Page 30 GAO-03-581 Environmental Protection 

transportation planners identified with the conformity process. Therefore, 

we believe this issue merits further assessment by EPA to determine if 

there is a possible solution, as we have recommended. 

The EPA representatives also said they thought it was important to point 

out not only the number of areas that have experienced a lapse, but also 

the number of times an individual conformity demonstration resulted in a 

lapse. While EPA did not have actual data to provide this statistic, the 

agency estimated that since 1997, areas most likely conducted a total of 

between 550 to 600 conformity demonstrations and that only 10 percent of 

these demonstrations resulted in a lapse. Finally, EPA suggested some 

technical changes throughout the report that we have incorporated as 

appropriate. 

As agreed with your office, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 10 days from the 

report date. At that time, we will send copies of this report to the 

appropriate congressional committees; the Secretary of Transportation; 

the Administrator, EPA; Director, Office of Management and Budget; and 

other interested parties. We also will make copies available to others upon 

request. In addition, the report will be available at no charge on the GAO 

Web site at http://www.gao.gov. If you or your staffs have any questions, 

please call me at (202) 512- 3841. Key contributors to this report were 

Teresa Dee, Elizabeth Erdmann, Samantha Goodman, Stuart Kaufman, 

Eileen Larence, Jonathan McMurray, and Anne Rhodes-Kline. 

John B. Stephenson 

Director, Natural Resources 

 and Environment 
Appendix I: Objectives, Scope, and 

Methodology 

Page 31 GAO-03-581 Environmental Protection 

The Ranking Minority Member of the Senate Environment and Public 

Works Committee, and Senator Lieberman asked us to determine (1) how 

many areas of the country have had their conformity lapse at least once 

since 1997 (the earliest date for which data are available), why, and what 

corrective actions were taken, and (2) what issues have planners 

encountered with the conformity process and the extent to which each of 

the proposed changes to the transportation planning process will address 

these issues. 

To address the first objective, we analyzed datasets supplied by the 

Environmental Protection Agency (EPA) and Department of 

Transportation (DOT) that listed the conformity lapses that have occurred 

in nonattainment or maintenance areas over the last several years. EPA’s 

Office of Transportation and Air Quality provided information supplied by 

its regional offices on lapses occurring since August 1997. The Federal 

Highway Administration, the agency within DOT that, along with the 

Federal Transit Administration, is directly responsible for making 

conformity determinations, provided information on lapses that have 

occurred since July 1999. 

We compared the data provided by both agencies to create a single, more 

comprehensive, and accurate dataset of all conformity lapses that have 

occurred since August 1997. We discussed and corrected any 

discrepancies between the two datasets with each agency and achieved 

consensus on a method to summarize and categorize the individual data 

points. In addition, to the extent possible, we corroborated lapse 

information we obtained from the agencies with information we obtained 

directly from the transportation planners in the areas with lapses. We 

obtained this latter information through our survey of each of the 341 local 

transportation planning organizations responsible for the conformity 

process in nonattainment and maintenance areas around the country. 

Furthermore, to fill in any remaining gaps in information on the causes of, 

and solutions to, conformity lapses, we conducted telephone interviews 

with the relevant transportation planners in those areas. 

To determine the accuracy and completeness of each agency’s data and 

their validity in providing evidence to support our findings, conclusions, 

and recommendations, we performed a data reliability assessment. All 

available information indicated the data to be sufficiently reliable for these 

purposes; corroborating evidence was strong and provided additional 

information necessary to ensure that the final consolidated dataset was 

accurate and relevant. To conduct this assessment, we subjected the 

datasets to documented standards that determine the sufficiency, 

Appendix I: Objectives, Scope, and 

Methodology 
Appendix I: Objectives, Scope, and 

Methodology 

Page 32 GAO-03-581 Environmental Protection 

competence, and relevance of supporting evidence. More specifically, we 

verified three data components that were key to our findings: (1) the 

location of nonattainment areas that have experienced a conformity lapse 

since 1997, (2) the reasons or contributing factors for each conformity 

lapse, and (3) the solutions or steps areas took to resolve each lapse. 

To address the second objective, we conducted an Internet-based survey 

of the 341 local transportation planning organizations in existence as of 

November 2002. The survey included questions addressing the current 

requirements for updating the short- and long-range transportation plans, 

the current requirements for demonstrating conformity, and proposed 

changes to the transportation planning and conformity requirements. We 

did not attempt to gain information from the state departments of 

transportation, which are responsible for transportation planning in those 

areas without a designated local transportation planning organization. We 

did not do so because the areas that the state departments of 

transportation cover are relatively small—with a population less than 

50,000. However, to help ensure that we identified any unique issues that 

these smaller areas may have with the conformity requirements, we met 

with officials of the American Association of State Highway and 

Transportation Officials. Its members are the state agencies that would 

conduct the conformity demonstrations for the smaller areas in their 

jurisdictions. 

We also conducted an Internet-based survey of the 50 state air quality 

agencies, plus air quality planners in the District of Columbia and Puerto 

Rico. These offices are responsible for preparing the state implementation 

plan (SIP), which is a detailed description of the programs that a state will 

use to carry out its responsibilities under the Clean Air Act to reduce air 

pollution. This survey included questions concerning the air quality and 

transportation planning processes, including conformity. Both surveys 

were pretested with potential respondents to ensure that (1) the questions 

were clear and unambiguous, (2) the terms we used were precise, (3) the 

survey did not place an undue burden on the agency officials completing 

it, and (4) the survey was independent and unbiased. 

The practical difficulties of conducting surveys may introduce errors into 

the results. Although we administered our survey to all known members of 

both populations, and thus our results are not subject to sampling error, 

nonresponse to the entire survey or individual questions can introduce a 

similar type of variability or bias into our results—to the extent that those 

not responding differ from those who do respond in how they would have 

answered our survey questions. We took steps in the design, data 
Appendix I: Objectives, Scope, and 

Methodology 

Page 33 GAO-03-581 Environmental Protection 

collection, and analysis phases of our survey to minimize population 

coverage, measurement, and data-processing errors. These steps included 

checking our population lists against known lists of planning 

organizations, pretesting and expert review of the questions in the survey 

instrument, and follow-up with those not reachable at original E-mail 

addresses or otherwise not immediately responding. 

The surveys were conducted using self-administered electronic 

questionnaires posted on the World Wide Web. We sent E-mail 

notifications to all 341 MPOs and 52 state air quality offices beginning on 

January 13, 2003, and January 22, 2003, respectively. We then sent each 

potential respondent a unique password and username by e-mail to ensure 

that only members of the target population could participate in the 

appropriate survey. To encourage respondents to complete the 

questionnaire, we sent an E-mail message to prompt each nonrespondent 

approximately 2 weeks after the initial e-mail message. We closed the 

surveys on February 28, 2003, and March 7, 2003, respectively. For the 

survey of transportation planners, we received a total of 253 responses, for 

an overall response rate of 74 percent. For the survey of state air quality 

offices, we received 45 out of 52 possible responses. Copies of each 

survey, with the quantitative results, can be found in appendixes II and III. 

For our analysis of the anticipated impact of the 8-hour ozone standard, 

we used listings of the counties currently in nonattainment and 

maintenance for the 1-hour standard and a listing of counties expected to 

violate the 8-hour standard, both found on EPA’s Web site. For the map 

depicting areas currently in nonattainment or maintenance for any of the 

criteria pollutants, we used county listings found on EPA’s Web site, coded 

and graphed each one using the counties’ Federal Information Processing 

Standards (FIPS) code. EPA’s estimate of the number of counties likely to 

be in violation of the 8-hour ozone standard is based on 3 years of 8-hour 

monitoring data during 1999 through 2001. The 1-hour ozone data include 

counties in nonattainment of the standard as of February 6, 2003. 

Furthermore, to address the second objective, we also interviewed 

cognizant officials and collected documented studies from the federal 

agencies administering air quality and transportation programs, as well as 

from relevant stakeholders. Specifically, we interviewed and gathered 

documentation from (1) EPA program managers in the Office of 

Transportation and Air Quality; (2) the Department of Transportation’s 

(DOT) program managers in the Federal Highway Administration, 

including the Office of Natural and Human Environment, and in the 

Federal Transit Administration’s Office of Planning; and (3) relevant 
Appendix I: Objectives, Scope, and 

Methodology 

Page 34 GAO-03-581 Environmental Protection 

stakeholders, including the following—the Association of Metropolitan 

Planning Organizations, American Association of State Highway and 

Transportation Officials, Environmental Defense, National Association of 

Regional Councils, and the State and Territorial Air Pollution Program 

Administrators/Association of Local Air Pollution Control Officials. 

We conducted our review from August 2002 through April 2003 in 

accordance with generally accepted government auditing standards.
Appendix II: Survey of Local Transportation 

Planners 

Page 35 GAO-03-581 Environmental Protection 

Appendix II: Survey of Local Transportation 

Planners 
Appendix II: Survey of Local Transportation 

Planners 

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Appendix II: Survey of Local Transportation 

Planners 

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Appendix II: Survey of Local Transportation 

Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Planners 

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Appendix III: Survey of State Air Quality 

Planners 

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Appendix III: Survey of State Air Quality 

Planners 
Appendix III: Survey of State Air Quality 

Planners 

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Appendix III: Survey of State Air Quality 

Planners 

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Appendix III: Survey of State Air Quality 

Planners 

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Appendix III: Survey of State Air Quality 

Planners 

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