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e-CFR Data is current as of September 8, 2010 

Title 40: Protection of Environment 

PART 93-DETERMINING CONFORMITY OF FEDERAL ACTIONS TO STATE OR FEDERAL 

IMPLEMENTATION PLANS 

Subpart A-Conformity to State or FederallmDlementation Plans of Transportation Plans Programs, 

and Projects Developed Funded or Approved Under Title 23 U,S,C, or the Federal Transit Laws 

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§ 93.109 Criteria and procedures for determining conformity of transportation plans, 

programs, and projects:.General. 

(a) In order for each transportation plan, program, and FHWAIFTA project to be found to conform, the 

MPO and DOT must demonstrate that the applicable criteria and procedures in this subpart are satisfied, 

and the MPO and DOT must comply with all applicable conformity requirements of implementation plans 

and of court orders for the area which pertain specifically to conformity. The criteria for making 

conformity determinations differ based on the action under review (transportation plans, TIPs, and 

FHWAIFTA projects), the relevant pollutant(s), and the status of the implementation plan, 

(b) Table 1 in this paragraph indicates the criteria and procedures in §§93, 11 0 through 93.119 which 

apply for transportation plans, TIPs, and FHWAIFTA projects. Paragraphs (c) through (k) of this section 

explain when the budget, interim emissions, and hot-spot tests are required for each pollutant and 

NAAQS. Paragraph (I) of this section addresses conformity requirements for areas with approved or 

adequate limited maintenance plans. Paragraph (m) of this section addresses nonattainment and 

maintenance areas which EPA has determined have insignificant motor vehicle emissions. Paragraph 

(n) of this section addresses isolated rural nonattainment and maintenance areas. Table 1 follows: 

Table 1-Conformity Criteria 

I

AII Actions at all times: I 

1__§"'-9_3_.1_1_0 1 Latest planning assumptions 

§93.111 1 Latest emissions model 

1 §93.112 IConsultation --=-----------1 Transportation Plan: ----­ 1

1

-------1 TIP:

Project (From a Conforming Plan and 

TIP): 

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§93.114 ICurrently conforming plan and TIP I I 

§93.115 IProject from a conforming plan and 

I TIP

§93.116 ICO, PM 10, and PM2.

shot-spots. I I 

I §93.117 IPM10and PM2.

Scontrol measures I 

Project (Not From a Conforming Plan 

and TIP): I I 

I §93.113(d) ITCMs I 

§93.114 ICurrently conforming plan and TIP I I 

§93.116 ICO, PM 10, and PM2.

shot-spots. I I 

§93.117 IPM 10and PM2.

Scontrol measures I I 

§93.118 and/or §93.119 IEm.iss.ions budget and/or Interim 

emiSSions I 

(c) 1-hour ozone NAAQS nonattainment and maintenance areas. This paragraph applies when an area 

is nonattainment or maintenance for the 1-hour ozone NAAQS (i.e., until the effective date of any 

revocation of the 1-hour ozone NAAQS for an area). In addition to the criteria listed in Table 1 in 

paragraph (b) of this section that are required to be satisfied at all times, in such ozone nonattainment 

and maintenance areas conformity determinations must include a demonstration that the budget and/or 

interim emissions tests are satisfied as described in the following: 

(1) In all 1-hour ozone nonattainment and maintenance areas the budget test must be satisfied as 

required by §93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan for the 1-hour ozone NAAQS is adequate for 

transportation conformity purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rulemaking. 

(2) In ozone nonattainment areas that are required to submit a control strategy implementation plan 

revision for the 1-hour ozone NAAQS (usually moderate and above areas), the interim emissions tests 

must be satisfied as required by §93.119 for conformity determinations made when there is no approved 

motor vehicle emissions budget from an applicable implementation plan for the 1-hour ozone NAAQS 

and no adequate motor vehicle emissions budget from a submitted control strategy implementation plan 

revision or maintenance plan for the 1-hour ozone NAAQS. 

(3) An ozone nonattainment area must satisfy the interim emissions test for NOx, as required by 

§93.119, if the implementation plan or plan submission that is applicable for the purposes of conformity 

determinations is a 15% plan or Phase I attainment demonstration that does not include a motor vehicle 

emissions budget for NOx ' The implementation plan for the 1-hour ozone NAAQS will be considered to 

establish a motor vehicle emissions budget for NOxif the implementation plan or plan submission 

contains an explicit NOxmotor vehicle emissions budget that is intended to act as a ceiling on future 

NOxemissions, and the NOxmotor vehicle emissions budget is a net reduction from NOxemissions 

levels in 1990. 

(4) Ozone nonattainment areas that have not submitted a maintenance plan and that are not required to 

submit a control strategy implementation plan revision for the 1-hour ozone NAAQS (usually marginal 

and below areas) must satisfy one of the following requirements: 

(i) The interim emissions tests required by §93.119; or 

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(ii) The State shall submit to EPA an implementation plan revision for the 1-hour ozone NAAQS that 

contains motor vehicle emissions bUdget(s) and a reasonable further progress or attainment 

demonstration, and the budget test required by §93.118 must be satisfied using the adequate or 

approved motor vehicle emissions budget(s) (as described in paragraph (c)(1) of this section). 

(5) Notwithstanding paragraphs (c)(1) and (c)(2) of this section, moderate and above ozone 

nonattainment areas with three years of clean data for the 1-hour ozone NAAQS that have not submitted 

a maintenance plan and that EPA has determined are not subject to the Clean Air Act reasonable further 

progress and attainment demonstration requirements for the 1-hour ozone NAAQS must satisfy one of 

the following requirements: 

(i) The interim emissions tests as required by §93.119; 

(ii) The budget test as required by §93.118, using the adequate or approved motor vehicle emissions 

budgets in the submitted or applicable control strategy implementation plan for the 1-hour ozone NAAQS 

(subject to the timing requirements of paragraph (c)(1) of this section); or 

(iii) The budget test as required by §93.118, using the motor vehicle emissions of ozone precursors in 

the most recent year of clean data as motor vehicle emissions budgets, if such budgets are established 

by the EPA rulemaking that determines that the area has clean data for the 1-hour ozone NAAQS. 

(d) 8-hour ozone NAAQS nonattainment and maintenance areas without motor vehicle emissions 

budgets for the 1-hour ozone NAAQS for any portion of the 8-hour nonattainment area. This paragraph 

applies to areas that were never designated nonattainment for the 1-hour ozone NAAQS and areas that 

were designated nonattainment for the 1-hour ozone NAAQS but that never submitted a control strategy 

SIP or maintenance plan with approved or adequate motor vehicle emissions budgets. This paragraph 

applies 1 year after the effective date of EPA's nonattainment designation for the 8-hour ozone NAAQS 

for an area, according to §93.1 02(d). In addition to the criteria listed in Table 1 in paragraph (b) of this 

section that are required to be satisfied at all times, in such 8-hour ozone nonattainment and 

maintenance areas conformity determinations must include a demonstration that the budget and/or 

interim emissions tests are satisfied as described in the following: 

(1) In such 8-hour ozone nonattainment and maintenance areas the budget test must be satisfied as 

required by §93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan for the 8-hour ozone NAAQS is adequate for 

transportation conformity purposes; 

(ii) The pUblication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rUlemaking. 

(2) In ozone nonattainment areas that are required to submit a control strategy implementation plan 

revision for the 8-hour ozone NAAQS (usually moderate and above and certain Clean Air Act, part D, 

subpart 1 areas), the interim emissions tests must be satisfied as required by §93.119 for conformity 

determinations made when there is no approved motor vehicle emissions bUdget from an applicable 

implementation plan for the 8-hour ozone NAAQS and no adequate motor vehicle emissions budget 

from a submitted control strategy implementation plan revision or maintenance plan for the 8-hour ozone 

NAAQS. 

(3) Such an 8-hour ozone nonattainment area must satisfy the interim emissions test for NOx, as 

required by §93.119, if the implementation plan or plan submission that is applicable for the purposes of 

conformity determinations is a 15% plan or other control strategy SIP that addresses reasonable further 

progress that does not include a motor vehicle emissions bUdget for NOx. The implementation plan for 

the 8-hour ozone NAAQS will be considered to establish a motor vehicle emissions budget for NOxif the 

implementation plan or plan submission contains an explicit NOxmotor vehicle emissions bUdget that is 

intended to act as a ceiling on future NOxemissions, and the NOxmotor vehicle emissions bUdget is a 

net reduction from NOxemissions levels in 2002. 

(4) Ozone nonattainment areas that have not submitted a maintenance plan and that are not required to 

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submit a control strategy implementation plan revision for the 8-hour ozone NAAQS (usually marginal 

and certain Clean Air Act, part D, subpart 1 areas) must satisfy one of the following requirements: 

(i) The interim emissions tests required by §93.119; or 

(ii) The State shall submit to EPA an implementation plan revision for the 8-hour ozone NAAQS that 

contains motor vehicle emissions budget(s) and a reasonable further progress or attainment 

demonstration, and the budget test required by §93.118 must be satisfied using the adequate or 

approved motor vehicle emissions bUdget(s) (as described in paragraph (d)(1) of this section). 

(5) Notwithstanding paragraphs (d)(1) and (d)(2) of this section, ozone nonattainment areas with three 

years of clean data for the 8-hour ozone NAAQS that have not submitted a maintenance plan and that 

EPA has determined are not sUbject to the Clean Air Act reasonable further progress and attainment 

demonstration requirements for the 8-hour ozone NAAQS must satisfy one of the following 

requirements: 

(i) The interim emissions tests as required by §93.119; 

(ii) The budget test as required by §93.118, using the adequate or approved motor vehicle emissions 

budgets in the submitted or applicable control strategy implementation plan for the 8-hour ozone NAAQS 

(subject to the timing requirements of paragraph (d)(1) of this section); or 

(iii) The budget test as required by §93.118, using the motor vehicle emissions of ozone precursors in 

the most recent year of clean data as motor vehicle emissions budgets, if such bUdgets are established 

by the EPA rulemaking that determines that the area has clean data for the 8-hour ozone NAAQS. 

(e) B-hour ozone NAAQS nonattainment and maintenance areas with motor vehicle emissions budgets 

for the i-hour ozone NAAQS that cover all or a portion of the B-hour nonattainment area. This provision 

applies 1 year after the effective date of EPA's nonattainment designation for the 8-hour ozone NAAQS 

for an area, according to §93.1 02(d). In addition to the criteria listed in Table 1 in paragraph (b) of this 

section that are required to be satisfied at all times, in such 8-hour ozone nonattainment and 

maintenance areas conformity determinations must include a demonstration that the budget and/or 

interim emissions tests are satisfied as described in the following: 

(1) In such 8-hour ozone nonattainment and maintenance areas the budget test must be satisfied as 

required by §93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan for the 8-hour ozone NAAQS is adequate for 

transportation conformity purposes; 

(ii) The pUblication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rulemaking. 

(2) Prior to paragraph (e)(1) of this section applying, the following test(s) must be satisfied: 

(i) If the 8-hour ozone nonattainment area covers the same geographic area as the 1-hour ozone 

nonattainment or maintenance area(s), the budget test as required by §93.118 using the approved or 

adequate motor vehicle emissions budgets in the 1-hour ozone applicable implementation plan or 

implementation plan submission; 

(ii) If the 8-hour ozone nonattainment area covers a smaller geographic area within the 1-hour ozone 

nonattainment or maintenance area(s), the budget test as required by §93.118 for either: 

(A) The 8-hour nonattainment area using corresponding portion(s) of the approved or adequate motor 

vehicle emissions budgets in the 1-hour ozone applicable implementation plan or implementation plan 

submission where such portion(s) can reasonably be identified through the interagency consultation 

process required by §93.105; or 

(6) The 1-hour nonattainment area using the approved or adequate motor vehicle emissions bUdgets in 

the 1-hour ozone applicable implementation plan or implementation plan submission. If additional 

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emissions reductions are necessary to meet the budget test for the 8-hour ozone NAAQS in such cases, 

these emissions reductions must come from within the 8-hour nonattainment area; 

(iii) If the 8-hour ozone nonattainment area covers a larger geographic area and encompasses the entire 

1-hour ozone nonattainment or maintenance area(s): 

(A) The budget test as required by §93.118 for the portion of the 8-hour ozone nonattainment area 

covered by the approved or adequate motor vehicle emissions budgets in the 1-hour ozone applicable 

implementation plan or implementation plan submission; and 

(8) The interim emissions tests as required by §93.119 for either: the portion of the 8-hour ozone 

nonattainment area not covered by the approved or adequate budgets in the 1-hour ozone 

implementation plan, the entire 8-hour ozone nonattainment area, or the entire portion of the 8-hour 

ozone nonattainment area within an individual state, in the case where separate 1-hour SIP budgets are 

established for each state of a multi-state 1-hour nonattainment or maintenance area; 

(iv) If the 8-hour ozone nonattainment area partially covers a 1-hour ozone nonattainment or 

maintenance area(s): 

(A) The budget test as required by §93.118 for the portion of the 8-hour ozone nonattainment area 

covered by the corresponding portion of the approved or adequate motor vehicle emissions budgets in 

the 1-hour ozone applicable implementation plan or implementation plan submission where they can be 

reasonably identified through the interagency consultation process required by §93.1 05; and 

(8) The interim emissions tests as required by §93.119, when applicable, for either: the portion of the 8­

hour ozone nonattainment area not covered by the approved or adequate budgets in the 1-hour ozone 

implementation plan, the entire 8-hour ozone nonattainment area, or the entire portion of the 8-hour 

ozone nonattainment area within an individual state, in the case where separate 1-hour SIP budgets are 

established for each state in a multi-state 1-hour nonattainment or maintenance area. 

(3) Such an 8-hour ozone nonattainment area must satisfy the interim emissions test for NOx ' as 

required by §93.119, if the only implementation plan or plan submission that is applicable for the 

purposes of conformity determinations is a 15% plan or other control strategy SI P that addresses 

reasonable further progress that does not include a motor vehicle emissions budget for NOx ' The 

implementation plan for the 8-hour ozone NAAQS will be considered to establish a motor vehicle 

emissions budget for NOxif the implementation plan or plan submission contains an explicit NOxmotor 

vehicle emissions budget that is intended to act as a ceiling on future NOxemissions, and the NOxmotor 

vehicle emissions budget is a net reduction from NOxemissions levels in 2002. Prior to an adequate or 

approved NOxmotor vehicle emissions budget in the implementation plan submission for the 8-hour 

ozone NAAQS, the implementation plan for the 1-hour ozone NAAQS will be considered to establish a 

motor vehicle emissions budget for NOxif the implementation plan contains an explicit NOxmotor vehicle 

emissions budget that is intended to act as a ceiling on future NOxemissions, and the NOxmotor vehicle 

emissions budget is a net reduction from NOxemissions levels in 1990. 

(4) Notwithstanding paragraphs (e)(1) and (e)(2) of this section, ozone nonattainment areas with three 

years of clean data for the 8-hour ozone NAAQS that have not submitted a maintenance plan and that 

EPA has determined are not subject to the Clean Air Act reasonable further progress and attainment 

demonstration requirements for the 8-hour ozone NAAQS must satisfy one of the following 

requirements: 

(i) The bUdget test and/or interim emissions tests as required by §§93.118 and 93.119 and as described 

in paragraph (e)(2) of this section; 

(ii) The budget test as required by §93.118, using the adequate or approved motor vehicle emissions 

budgets in the submitted or applicable control strategy implementation plan for the 8-hour ozone NAAQS 

(subject to the timing requirements of paragraph (e)(1) of this section); or 

(iii) The budget test as required by §93.118, using the motor vehicle emissions of ozone precursors in 

the most recent year of clean data as motor vehicle emissions budgets, if such budgets are established 

by the EPA rulemaking that determines that the area has clean data for the 8-hour ozone NAAQS. 

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(f) co nonattainment and maintenance areas. In addition to the criteria listed in Table 1 in paragraph (b) 

of this section that are required to be satisfied at all times, in CO nonattainment and maintenance areas 

conformity determinations must include a demonstration that the hot-spot, budget and/or interim 

emissions tests are satisfied as described in the following: 

(1) FHWAIFTA projects in CO nonattainment or maintenance areas must satisfy the hot spot test 

required by §93.116(a) at all times. Until a CO attainment demonstration or maintenance plan is 

approved by EPA, FHWAIFTA projects must also satisfy the hot spot test required by §93.116(b). 

(2) In CO nonattainment and maintenance areas the budget test must be satisfied as required by 

§93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions bUdget in a submitted control 

strategy implementation plan revision or maintenance plan is adequate for transportation conformity 

purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rulemaking. 

(3) Except as provided in paragraph (f)(4) of this section, in CO nonattainment areas the interim 

emissions tests must be satisfied as required by §93.119 for conformity determinations made when 

there is no approved motor vehicle emissions budget from an applicable implementation plan and no 

adequate motor vehicle emissions budget from a submitted control strategy implementation plan revision 

or maintenance plan. 

(4) CO nonattainment areas that have not submitted a maintenance plan and that are not required to 

submit an attainment demonstration (e.g., moderate CO areas with a design value of 12.7 ppm or less or 

not classified CO areas) must satisfy one of the following requirements: 

(i) The interim emissions tests required by §93.119; or 

(ii) The State shall submit to EPA an implementation plan revision that contains motor vehicle emissions 

bUdget(s) and an attainment demonstration, and the budget test required by §93.118 must be satisfied 

using the adequate or approved motor vehicle emissions budget(s) (as described in paragraph (f)(2) of 

this section). 

(g) PM 10 nonattainment and maintenance areas. In addition to the criteria listed in Table 1 in paragraph 

(b) of this section that are required to be satisfied at all times, in PM1Qnonattainment and maintenance 

areas conformity determinations must include a demonstration that the hot-spot, bUdget and/or interim 

emissions tests are satisfied as described in the following: 

(1) FHWAIFTA projects in PM1Qnonattainment or maintenance areas must satisfy the hot spot test 

required by §93.116(a). 

(2) In PM 10nonattainment and maintenance areas where a budget is submitted for the 24-hour 

PM1QNAAQS, the budget test must be satisfied as required by §93.118 for conformity determinations 

made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan is adequate for transportation conformity 

purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rulemaking. 

(3) Prior to paragraph (g)(2) of this section applying, the budget test must be satisfied as required by 

§93.118 using the approved or adequate motor vehicle emissions budget established for the revoked 

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annual PM1QNAAQS, if such a budget exists. 

(4) In PM1Qnonattainment areas the interim emissions tests must be satisfied as required by §93.119 for 

conformity determinations made: 

(i) If there is no approved motor vehicle emissions budget from an applicable implementation plan and 

no adequate motor vehicle emissions bUdget from a submitted control strategy implementation plan 

revision or maintenance plan; or 

(ii) If the submitted implementation plan revision is a demonstration of impracticability under CAA section 

189(a)(1 )(8)(ii) and does not demonstrate attainment. 

(h) NO 2 nonattainment and maintenance areas. In addition to the criteria listed in Table 1 in paragraph 

(b) of this section that are required to be satisfied at all times, in N02nonattainment and maintenance 

areas conformity determinations must include a demonstration that the budget and/or interim emissions 

tests are satisfied as described in the following: 

(1) In N02nonattainment and maintenance areas the budget test must be satisfied as required by 

§93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan is adequate for transportation conformity 

purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a bUdget in theFederal Register,if such approval is 

completed through direct final rulemaking. 

(2) In N02nonattainment areas the interim emissions tests must be satisfied as required by §93.119 for 

conformity determinations made when there is no approved motor vehicle emissions budget from an 

applicable implementation plan and no adequate motor vehicle emissions budget from a submitted 

control strategy implementation plan revision or maintenance plan. 

(i) 1997 PM 2.5 NAAQS nonattainment and maintenance areas. In addition to the criteria listed in Table 

1 in paragraph (b) of this section that are required to be satisfied at all times, in such 1997 

PM2.

Snonattainment and maintenance areas conformity determinations must include a demonstration 

that the budget and/or interim emissions tests are satisfied as described in the following: 

(1) FHWAIFTA projects in such 1997 PM2.

Snonattainment or maintenance areas must satisfy the 

appropriate hot-spot test required by §93.116(a). 

(2) In such 1997 PM2.

Snonattainment and maintenance areas the budget test must be satisfied as 

required by §93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan is adequate for transportation conformity 

purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register; or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is
 

completed through direct final rulemaking.
 

(3) In such 1997 PM2.

Snonattainment areas the interim emissions tests must be satisfied as required by 

§93.119 for conformity determinations made if there is no approved motor vehicle emissions budget 

from an applicable implementation plan and no adequate motor vehicle emissions budget from a 

submitted control strategy implementation plan revision or maintenance plan. 

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m2006 PM 2.5 NAAQS nonattainment and maintenance areas without 1997 PM 2.5 NAAQS motor 

vehicle emissions budgets for any portion of the 2006 PM 2.5 NAAQS area. In addition to the criteria 

listed in Table 1 in paragraph (b) of this section that are required to be satisfied at all times, in such 2006 

PM2.

Snonattainment and maintenance areas conformity determinations must include a demonstration 

that the budget and/or interim emissions tests are satisfied as described in the folloWing: 

(1) FHWAIFTA projects in such PM2.

Snonattainment and maintenance areas must satisfy the 

appropriate hot-spot test required by §93.116(a). 

(2) In such PM2.

Snonattainment and maintenance areas the budget test must be satisfied as required by 

§93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions bUdget in a submitted control 

strategy implementation plan revision or maintenance plan for the 2006 PM2.

sNAAQS is adequate for 

transportation conformity purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register;or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register, if such approval is 

completed through direct final rulemaking. 

(3) In such PM2.

Snonattainment areas the interim emissions tests must be satisfied as required by 

§93.119 for conformity determinations made if there is no approved motor vehicle emissions budget 

from an applicable implementation plan for the 2006 PM2.

sNAAQS and no adequate motor vehicle 

emissions budget from a submitted control strategy implementation plan revision or maintenance plan 

for the 2006 PM2.

sNAAQS. 

(k) 2006 PM 2.5 NAAQS nonattainment and maintenance areas with motor vehicle emissions budgets 

for the 1997 PM 2.5 NAAQS that cover all or a portion of the 2006 PM 2.5 nonattainment area. In 

addition to the criteria listed in Table 1 in paragraph (b) of this section that are required to be satisfied at 

all times, in such 2006 PM2.

Snonattainment and maintenance areas conformity determinations must 

include a demonstration that the bUdget and/or interim emissions tests are satisfied as described in the 

following: 

(1) FHWAIFTA projects in such PM2.

Snonattainment and maintenance areas must satisfy the 

appropriate hot-spot test required by §93.116(a). 

(2) In such PM2.

Snonattainment and maintenance areas the budget test must be satisfied as required by 

§93.118 for conformity determinations made on or after: 

(i) The effective date of EPA's finding that a motor vehicle emissions budget in a submitted control 

strategy implementation plan revision or maintenance plan for the 2006 PM2. NAAQS is adequate for s

transportation conformity purposes; 

(ii) The publication date of EPA's approval of such a budget in theFederal Register;or 

(iii) The effective date of EPA's approval of such a budget in theFederal Register,if such approval is 

completed through direct final rUlemaking. 

(3) Prior to paragraph (k)(2) of this section applying, the following test(s) must be satisfied: 

(i) If the 2006 PM2.

Snonattainment area covers the same geographic area as the 1997 

PM2.

Snonattainment or maintenance area(s), the budget test as required by §93.118 using the approved 

or adequate motor vehicle emissions budgets in the 1997 PM2.

Sapplicable implementation plan or 

implementation plan submission; 

(ii) If the 2006 PM2.

Snonattainment area covers a smaller geographic area within the 1997 

PM2Snonattainment or maintenance area(s), the budget test as required by §93.118 for either: 

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(A) The 2006 PM nonattainment area using corresponding portion(s) of the approved or adequate 2.

5

motor vehicle emissions budgets in the 1997 PM2.

5applicable implementation plan or implementation 

plan submission where such portion(s) can reasonably be identified through the interagency consultation 

process required by §93.1 05; or 

(8) The 1997 PM2.

5nonattainment area using the approved or adequate motor vehicle emissions 

budgets in the 1997 PM applicable implementation plan or implementation plan submission. If 2.

5

additional emissions reductions are necessary to meet the budget test for the 2006 PM2.

5NAAQS in 

such cases, these emissions reductions must come from within the 2006 PM25nonattainment area; 

(iii) If the 2006 PM2.

5nonattainment area covers a larger geographic area and encompasses the entire 

1997 PM25nonattainment or maintenance area(s): 

(A) The budget test as required by §93.118 for the portion of the 2006 PM2.

5nonattainment area covered 

by the approved or adequate motor vehicle emissions budgets in the 1997 PM25applicabie 

implementation plan or implementation plan submission; and the interim emissions tests as required by 

§93.119 for either: the portion of the 2006 PM2.

5nonattainment area not covered by the approved or 

adequate budgets in the 1997 PM 2.

5implementation plan, the entire 2006 PM 2.5nonattainment area, or 

the entire portion of the 2006 PM25nonattainment area within an individual state, in the case where 

separate 1997 PM2.

5SIP budgets are established for each state of a multi-state 1997 

PM2.

5nonattainment or maintenance area; or 

(8) The budget test as required by §93.118 for the entire 2006 PM2.

5nonattainment area using the 

approved or adequate motor vehicle emissions budgets in the applicable 1997 PM 2.

5implementation 

plan or implementation plan submission. 

(iv) If the 2006 PM2.

5nonattainment area partially covers a 1997 PM25nonattainment or maintenance 

area(s): 

(A) The bUdget test as required by §93.118 for the portion of the 2006 PM2.

5nonattainment area covered 

by the corresponding portion of the approved or adequate motor vehicle emissions budgets in the 1997 

PM2.

5applicable implementation plan or implementation plan submission where they can be reasonably 

identified through the interagency consultation process required by §93.105; and 

(8) The interim emissions tests as required by §93.119, when applicable, for either: The portion of the 

2006 PM25nonattainment area not covered by the approved or adequate budgets in the 1997 

PM2.

5implementation plan, the entire 2006 PM 2.

5nonattainment area, or the entire portion of the 2006 

PM2.

5nonattainment area within an individual state, in the case where separate 1997 PM2.

5SIP budgets 

are established for each state in a multi-state 1997 PM2.

5nonattainment or maintenance area. 

(I) Areas with limited maintenance plans. Notwithstanding the other paragraphs of this section, an area is 

not required to satisfy the regional emissions analysis for §93.118 andlor §93.119 for a given pollutant 

and NAAQS, if the area has an adequate or approved limited maintenance plan for such pollutant and 

NAAQS. A limited maintenance plan would have to demonstrate that it would be unreasonable to expect 

that such an area would experience enough motor vehicle emissions growth for a NAAQS violation to 

occur. A conformity determination that meets other applicable criteria in Table 1 of paragraph (b) of this 

section is still required, including the hot-spot requirements for projects in CO, PM 10, and PM2.

5areas. 

(m) Areas with insignificant motor vehicle emissions. Notwithstanding the other paragraphs in this 

section, an area is not required to satisfy a regional emissions analysis for §93.118 andlor §93.119 for a 

given pollutanUprecursor and NAAQS, if EPA finds through the adequacy or approval process that a SIP 

demonstrates that regional motor vehicle emissions are an insignificant contributor to the air quality 

problem for that poliutanUprecursor and NAAQS. The Sl P would have to demonstrate that it would be 

unreasonable to expect that such an area would experience enough motor vehicle emissions growth in 

that pollutanUprecursor for a NAAQS violation to occur. Such a finding would be based on a number of 

factors, including the percentage of motor vehicle emissions in the context of the total SIP inventory, the 

current state of air quality as determined by monitoring data for that NAAQS, the absence of SI P motor 

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

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Electronic Code of Federal Regulations: Page 10 of 11 

emissions. A conformity determination that meets other applicable criteria in Table 1 of paragraph (b) of 

this section is still required, including regional emissions analyses for §93.118 and/or §93.119 for other 

pollutants/precursors and NAAQS that apply. Hot-spot requirements for projects in CO, PM1Q' and 

PM2Sareas in §93.116 must also be satisfied, unless EPA determines that the SIP also demonstrates 

that projects will not create new localized violations and/or increase the severity or number of existing 

violations of such NAAQS. If EPA subsequently finds that motor vehicle emissions of a given 

pollutant/precursor are significant, this paragraph would no longer apply for future conformity 

determinations for that pollutant/precursor and NAAQS. 

(n) Isolated rural nonattainment and maintenance areas. This paragraph applies to any nonattainment or 

maintenance area (or portion thereof) which does not have a metropolitan transportation plan or TIP and 

whose projects are not part of the emissions analysis of any MPO's metropolitan transportation plan or 

TIP. This paragraph does not apply to "donut" areas which are outside the metropolitan planning 

boundary and inside the nonattainment/maintenance area boundary. 

(1) FHWAIFTA projects in all isolated rural nonattainment and maintenance areas must satisfy the 

requirements of §§93.11 0, 93.111, 93.112, 93.113(d), 93.116, and 93.117. Until EPA approves the 

control strategy implementation plan or maintenance plan for a rural CO nonattainment or maintenance 

area, FHWAIFTA projects must also satisfy the requirements of §93.116(b) ("Localized CO, PM 10• and 

PM2Svioiations (hot spots)"). 

(2) Isolated rural nonattainment and maintenance areas are subject to the budget and/or interim 

emissions tests as described in paragraphs (c) through (m) of this section, with the following 

modifications: 

(i) When the requirements of §§93.1 06(d), 93.116, 93.118, and 93.119 apply to isolated rural 

nonattainment and maintenance areas, references to "transportation plan" or "TIP" should be taken to 

mean those projects in the statewide transportation plan or statewide TIP which are in the rural 

nonattainment or maintenance area. When the requirements of §93.1 06(d) apply to isolated rural 

nonattainment and maintenance areas, references to "MPO" should be taken to mean the state 

department of transportation. 

(ii) In isolated rural nonattainment and maintenance areas that are subject to §93.118, FHWAIFTA 

projects must be consistent with motor vehicle emissions budget(s) for the years in the timeframe of the 

attainment demonstration or maintenance plan. For years after the attainment year (if a maintenance 

plan has not been submitted) or after the last year of the maintenance plan, FHWAIFTA projects must 

satisfy one of the following requirements: 

(A) §93.118; 

(8) §93.119 (including regional emissions analysis for NOxin all ozone nonattainment and maintenance 

areas, notwithstanding §93.119(f)(2»; or 

(C) As demonstrated by the air quality dispersion model or other air quality modeling technique used in 

the attainment demonstration or maintenance plan, the FHWAIFTA project, in combination with all other 

regionally significant projects expected in the area in the timeframe of the statewide transportation plan, 

must 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 emission reductions or other milestones in any area. Control measures 

assumed in the analysis must be enforceable. 

(iii) The choice of requirements in paragraph (n)(2)(ii) of this section and the methodology used to meet 

the requirements of paragraph (n)(2)(ii)(C) of this section must be determined through the interagency 

consultation process required in §93.1 05(c)(1)(vii) through which the relevant recipients of title 23 U.S.C. 

or Federal Transit Laws funds, the local air quality agency, the State air quality agency, and the State 

department of transportation should reach consensus about the option and methodology selected. EPA 

and DOT must be consulted through this process as well. In the event of unresolved disputes, conflicts 

may be escalated to the Governor consistent with the procedure in §93.1 05(d), which applies for any 

State air agency comments on a conformity determination. 

[62 FR 43801, Aug. 15, 1997, as amended at 69 FR 40093, July 1, 2004; 71 FR 12510, Mar. 10, 2006; 

73 FR 4440, Jan. 24, 2008; 75 FR 14284, Mar. 24, 2010] 

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