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Transportation Conformity Reference Guide

Section A: Overview of the Transportation Conformity Process and Requirements

What Is Transportation Conformity?
Applicability of Transportation Conformity Requirements
What Actions Are Subject to Transportation Conformity?

Who Makes Conformity Determinations?
Where Does Transportation Conformity Apply?
Which Pollutants or Pollutant Precursors Does Transportation Conformity Apply?
Frequency of Transportation Conformity Determinations
When Is a Transportation Conformity Determination Required?

How Often Must Conformity Be Determined?
When Does the Four-year Clock Start for a Transportation Plan or TIP?
What Is a Conformity Lapse?
What Are the Major Requirements of the Transportation Conformity process?

Exhibit A-1: Transportation Conformity Process

This Section provides information on:

The statutory basis for transportation conformity is found in the Clean Air Act Amendments (CAA) of 1990[1]. In addition, the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991[2], the Transportation Equity Act for the 21st Century (TEA-21)[3], and the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU)[4] reinforced the need for coordinated transportation and air quality planning through the metropolitan planning provisions. The CAA conformity provisions are interpreted through regulations that set out the procedures and criteria for compliance. The regulations governing implementation requirements are included in the Environmental Protection Agency's (EPA) transportation conformity rule[5] and the metropolitan transportation planning regulations[6].

What Is Transportation Conformity?

Transportation conformity is a way to ensure that Federal funding and approval are given to those transportation activities that are consistent with air quality goals. It ensures that these transportation activities do not worsen air quality or interfere with the "purpose" of the SIP, which is to meet the NAAQS[7]. Meeting the NAAQS often requires emissions reductions from mobile sources.

According to the CAA, transportation plans, programs, and projects cannot:

Applicability of Transportation Conformity Requirements

Below we discuss the applicability of the transportation conformity requirements including a description of the requirements, where they apply and when they apply. The transportation conformity rule includes the following provisions on applicability:

40 CFR §93.102, Applicability

  1. Action applicability.
    1. Except as provided for in paragraph (c) of this section or §93.126, conformity determinations are required for:
      1. The adoption, acceptance, approval or support of transportation plans and transportation plan amendments developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT;
      2. The adoption, acceptance, approval or support of TIPs and TIP amendments developed pursuant to 23 CFR part 450 or 49 CFR part 613 by an MPO or DOT; and
      3. The approval, funding, or implementation of FHWA/FTA projects.
    2. Conformity determinations are not required under this rule for individual projects which are not FHWA/FTA projects. However, §93.121 applies to such projects if they are regionally significant.
  2. Geographic Applicability. The provisions of this subpart shall apply in all nonattainment and maintenance areas for transportation-related criteria pollutants for which the area is designated nonattainment or has a maintenance plan.
    1. The provisions of this subpart apply with respect to emissions of the following criteria pollutants; ozone, carbon monoxide (CO), nitrogen dioxide (NO2), particles with an aerodynamic diameter less than or equal to a nominal 10 micrometers (PM10); and particles with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers (PM2.5).
    2. The provisions of this subpart also apply with respect to emissions of the following precursor pollutants:
      1. Volatile organic compounds (VOC) and nitrogen oxides (NOx) in ozone areas;
      2. NOx in NO2 areas; and
      3. VOC and/or NOx in PM10 areas if the EPA Regional Administrator or the director of the State air agency has made a finding that transportation-related emissions of one or both of these precursors within the nonattainment area are a significant contributor to the PM10 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.
      4. NOx in PM2.5 areas, unless both the EPA Regional Administrator and the director of the state air agency have made a finding that the transportation-related emissions of NOx within the nonattainment area are not a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or the applicable implementation plan (or implementation plan submissions) does not establish an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy; and
      5. VOC, sulfur oxides (SOx) and/or ammonia (NH3) in PM2.5 areas either if the EPA Regional Administrator or the director of the state air agency has made a finding that transportation-related emissions of any of these precursors within the nonattainment area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.
    3. The provisions of this subpart apply to PM2.5 nonattainment and maintenance areas with respect to PM2.5 from re-entrained road dust if the EPA Regional Administrator or the director of the State air agency has made a finding that re-entrained road dust emissions within the area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) includes re-entrained road dust in the approved (or adequate) budget as part of the reasonable further progress, attainment or maintenance strategy. Re-entrained road dust emissions are produced by travel on paved and unpaved roads (including emissions from anti-skid and deicing materials).
    4. The provisions of this subpart apply to maintenance areas for 20 years from the date EPA approves the area's request under §107(d) of the CAA for redesignation to attainment, unless the applicable implementation plan specifies that the provisions of this subpart shall apply for more than 20 years.
  3. Limitations. In order to receive any FHWA/FTA approval or funding actions, including NEPA approvals, for a project phase subject to this subpart, a currently conforming transportation plan and TIP must be in place at the time of project approval as described in §93.114, except as provided by §93.114(b).
  4. Grace period for new nonattainment areas. For areas or portions of areas which have been continuously designated attainment or not designated for any NAAQS for ozone, CO, PM10, PM2.5, or NO2 since 1990 and are subsequently redesignated to nonattainment or designated for any NAAQS for any of these pollutants, the provisions of this subpart shall not apply with respect to that NAAQS for 12 months following the effective date of final designation to nonattainment for each NAAQS for such pollutant.

What Actions Are Subject to Transportation Conformity?

Exhibit A-1 provides an overview of the conformity process and shows the key components of a transportation conformity determination. Each of the components is discussed below.

Exhibit A-1
Transportation Conformity Process
click for text

Transportation Plans and Transportation Improvement Programs

58 FR 62190, Nov. 24, 1993
This rule applies only to the conformity of transportation plans, programs, and projects developed, funded, or approved under title 23 U.S.C. or the Federal Transit Act. Criteria and procedures for determining the conformity of all other Federal actions "general conformity" including highway and transit projects which require funding or approval from a Federal agency other than FHWA or FTA, are promulgated in a separate rule.

58 FR 62205, Nov. 24, 1993
Recipients of title 23 U.S.C. or Federal Transit Act funds include recipient agencies at any level of State, county, city, or regional government. Private landowners or developers, and contractors or grant recipients (including local government agencies) which are only paid for services or products created by their own employees, are not considered recipients of funds. That is, if an agency receives title 23 U.S.C. or Federal Transit Act funds and then uses the funds to pay private landowners or developers, contractors, or grant recipients, the private entities/contractors/grant recipients are not thereby considered recipients of Federal funds for the purposes of this requirement, and their other non-Federal projects would not be subject to this requirement. Furthermore, projects which do not involve any participation by recipients of Federal funds are not subject to this requirement.

The CAA requires that transportation plans, programs, and projects in nonattainment or maintenance areas that are funded or approved by the FHWA or FTA be in conformity with SIPs through the process described in the EPA's transportation conformity regulation.

Titles 23 and 49 United States Code (U.S.C.) require that MPOs have transportation plans in place that present a twenty-year perspective on transportation investments for the region. The transportation improvement program (TIP) is a multi-year prioritized list of fiscally constrained projects (at least four years). Please see the SAFETEA-LU interim guidance related to planning for information on the four year TIP: www.fhwa.dot.gov/hep/guidance/igslpja.cfm The TIP must be consistent with the conforming transportation plan, and the TIP must be found to conform to the SIP. Specifically, the transportation plan/TIP must result in emissions consistent with those allowed in the SIP. Regionally significant transportation projects, regardless of funding source, must be accounted for in the plan/TIP conformity analysis. In rural nonattainment or maintenance areas the State department of transportation must ensure that regionally significant Federally funded or approved projects conform to the SIP.

Project Level Conformity

FHWA/FTA projects must be found to conform before they are adopted, accepted, approved or funded. With some exceptions[8] (e.g. safety, landscaping and other projects with neutral or de minimis emissions impacts), transportation projects: 1) must come from a conforming transportation plan/TIP[9], 2) the design concept and scope of the project that was in place at the time of the conformity finding must be maintained through implementation, and 3) project design concept and scope had to be sufficiently defined to determine emissions at the time of the plan/TIP conformity determination. If a project does not meet the above three criteria, its emissions, when considered with the emissions projected for the conforming transportation plan and program, cannot cause the plan and program to exceed the emissions budget in the SIP. Areas that have carbon monoxide (CO) or particulate matter (PM10) problems must also show that new localized violations (or "hot spots") of those pollutants will not result from project implementation. EPA issued PM2.5 and revised PM10 hot spot analyses requirements in March 2006. This Guide has not been updated to reflect those changes.

Who Makes Conformity Determinations?

The MPO and U.S. DOT (FHWA/FTA) have a responsibility to ensure that the transportation plan and program within the metropolitan boundaries conform to the SIP. In metropolitan areas, the governing board of each MPO must formally make a conformity determination on its transportation plan/TIP prior to submitting them to the U.S. DOT (FHWA/FTA) for review and approval. Conformity determinations for projects outside of these boundaries are the responsibility of the U.S. DOT (FHWA/FTA) and the project sponsor, which usually is the State DOT.

In addition, the National Memorandum of Understanding issued on April 19, 2001, provides the EPA and DOT with a framework for coordinating and working through issues in the conformity and SIP processes. Specifically, the MOU's provisions ensure that:

  1. EPA and DOT consult on conformity determinations before DOT's approval process;
  2. the conformity rule's provisions are appropriately applied with regard to conformity determinations; and
  3. adequate interagency consultation persists through the planning and conformity processes to identify and resolve issues prior to a conformity lapse or freeze.

Where Does Transportation Conformity Apply?

Transportation conformity applies in the following areas[10]:

Which Pollutants or Pollutant Precursors Does Transportation Conformity Apply?

Transportation conformity applies to the following criteria pollutants:

Transportation conformity applies to the following precursor pollutants:

40 CFR §93.102(b)(2)(i-v)

  1. Volatile organic compounds (VOCs) and nitrogen oxides (NOx) in ozone nonattainment areas,
  2. NOx in nitrogen dioxide (NO2) areas;
  3. VOC and/or NOx in PM10 areas if the EPA Administrator or the director of the State air agency has made a finding that transportation-related emissions of one or both of these precursors within the nonattainment area are a significant contributor to the PM10 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.
  4. NOx in PM2.5 areas, unless the EPA Regional Administrator and the director of the state air agency have made a finding that transportation-related emissions of NOx with the nonattainment area are not significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or the applicable implementation plan (or implementation plan submission) does not establish an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy; and
  5. VOC, sulfur oxides (SOx) and/or ammonia (NH3) in PM2.5 areas either if the EPA Regional Administrator or the director of the state air agency has made a finding that transportation-related emissions of any of these precursors within the nonattainment area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submissions) establishes an approved (or adequate) budget for such emissions as part of the reasonable further progress, attainment or maintenance strategy.

In PM2.5 areas, re-entrained road dust applies under the following conditions:

"....if the EPA Regional Administrator or the director of the State air agency has made a finding that re-entrained road dust emissions within the area are a significant contributor to the PM2.5 nonattainment problem and has so notified the MPO and DOT, or if the applicable implementation plan (or implementation plan submission) includes re-entrained road dust in the approved (or adequate) budget as part of the reasonable further progress, attainment or maintenance strategy. Re-entrained road dust emissions are produced by travel on paved and unpaved roads (including emissions from anti-skid and deicing materials)." 40 CFR §93.102(b)(3)

Frequency of Transportation Conformity Determinations

Section 6011 of SAFETEA-LU affects the frequency of when conformity determinations are required for metropolitan plans and TIPs:

SAFETEA-LU section 6011(a) Conformity Redeterminations

This provision replaces the 18-month trigger with a 24-month trigger for transportation plan and TIP conformity determinations that are currently found at 40 CFR 93.104(e). It amends section 176(c)(2) of the Clean Air Act (42 U.S.C. §7506(c)) to read:

  1. The appropriate metropolitan planning organization shall redetermine conformity of existing transportation plans and program not later than 2 years after the date on which the Administrator
    1. finds a motor vehicle emissions budget to be adequate in accordance with section 93.118(e)(4) of title 40, Code of Federal Regulations (as in effect on October 1, 2004);
    2. approves an implantation plan that establishes a motor vehicle emissions budget if that budget has not yet been determined to be adequate in accordance with clause (i); or
    3. promulgates an implementation plan that establishes or revises a motor vehicle emission budget.

SAFETEA-LU section 6011(b) Frequency of Conformity Determination Updates

This provision replaces the 3-year conformity update cycle with a 4-year conformity update cycle for plans and TIPs. It amends section 176(c)(4)(B)(ii) of the Clean Air Act (42 U.S.C. §7506(c)(4)(B)(ii)) to read:

  1. address the appropriate frequency for making conformity determinations, but the frequency for making conformity determinations on updated transportation plans and programs shall be every 4 years, except in a case in which
    1. the metropolitan planning organization elects to update a transportation plan or program more frequently; or
    2. the metropolitan planning organization is required to determine conformity in accordance with paragraph (2)(E) [2-year trigger]

Note: The provisions of SAFETEA-LU supercede the applicable provisions in the Conformity Rule below, which will be amended.

40 CFR §93.104

  1. Conformity determinations and conformity redeterminations for transportation plans, TIPs, and FHWA/FTA projects must be made according to the requirements of this section and the application implementation plan.
  2. Frequency of conformity determinations for transportation plans.
    1. Each new transportation plan must be demonstrated to conform before the transportation plan is approved by the MPO or accepted by DOT.
    2. All transportation plan revisions must be found to conform before the transportation plan revisions are approved by the MPO or accepted by DOT, unless the revision merely adds or deletes exempt projects listed in §93.126 or §93.127. The conformity determination must be based on the transportation plan and the revision taken as a whole.
    3. The MPO and DOT must determine the conformity of the transportation plan (including a new regional emissions analysis) no less frequently than every three years. If more than three years elapse after DOT's conformity determination without the MPO and DOT determining conformity of the transportation plan, the existing conformity determination will lapse.
  3. Frequency of conformity determinations for transportation improvement programs.
    1. A new TIP must be demonstrated to conform before the TIP is approved by the MPO or accepted by DOT.
    2. A TIP amendment requires a new conformity determination for the entire TIP before the amendment is approved by the MPO or accepted by DOT, unless the amendment merely adds or deletes exempt projects listed in §93.126 or §93.127.
    3. The MPO and DOT must determine the conformity of the TIP (including a new regional emissions analysis) no less frequently than every three years. If more than three years elapse after DOT's conformity determination without the MPO and DOT determining conformity of the TIP, the existing conformity determination will lapse.
  4. Projects. FHWA/FTA projects must be found to conform before they are adopted, accepted, approved, or funded. Conformity must be redetermined for any FHWA/FTA project if one of the following occurs: a significant change in the project's design concept and scope; three years elapse since the most recent major step to advance the project; or initiation of a supplemental environmental document for air quality purposes. Major steps include NEPA process completion; start of final design; acquisition of a significant portion of the right-of-way; and, construction (including Federal approval of plans, specifications and estimates).
  5. Triggers for transportation plan and TIP conformity determinations. Conformity of existing transportation plans and TIPs must be redetermined within 18 months of the following, or the existing conformity determination will lapse, and no new project-level conformity determinations may be made until conformity of the transportation plan and TIP has been determined by the MPO and DOT:
    1. The effective date of EPA's finding that motor vehicle emissions budgets from an initially submitted control strategy implementation plan or maintenance plan are adequate pursuant to §93.118(e) and can be used for transportation conformity purposes;
    2. The effective date of EPA approval of a control strategy implementation plan revision or maintenance plan which establishes or revises a motor vehicle emissions budget if that budget has not yet been used in a conformity determination prior to approval; and
    3. The effective date of EPA promulgation of an implementation plan which establishes or revises a motor vehicle emissions budget.

When Is a Transportation Conformity Determination Required?

Conformity must be determined:

Conformity Grace Period for Newly Designated Nonattainment Areas

EPA designated areas nonattainment for the 8-hour standard on April 15, 2004 with an effective date of June 15, 2004. Therefore conformity for the 8-hour standard applied on June 15, 2005. Clean Air Act section 176(c)(6) and § 93.102(d) of the conformity regulation; provide a one-year grace period after the effective date of EPA's nonattainment designation for a pollutant or standard. Since the 1-hour ozone standard and the 8-hour ozone standard are different National Ambient Air Quality Standards (NAAQS) for the same pollutant, every area that was designated nonattainment under the 8-hour ozone standard had a one year grace period before conformity applied for that standard even if the area was previously designated nonattainment or maintenance under the 1-hour ozone standard.

EPA designated areas nonattainment for PM2.5 on January 5, 2005 with an effective date of April 5, 2005. Therefore, conformity for the PM2.5 standard will apply on April 5, 2006, and this will apply to every area that is designated nonattainment under the PM2.5 standard. If an area is designated nonattainment for both the 8-hour ozone standard and the PM2.5 standard, conformity for the 8-hour ozone standard applied one year after the effective date of an area's 8-hour designation, and conformity for PM2.5 areas will apply one year after the effective date of the area's PM2.5 designation (69 FR 40008, July 1, 2004). See Appendix A.

How Often Must Conformity Be Determined?[12]

When Does the Four-year Clock Start for a Transportation Plan or TIP?

The four-year clock[13] starts when the DOT makes the conformity determination on the MPO plan or TIP, not the date when the MPO transmits the plan to DOT. If four years elapse after the DOT makes a plan/TIP conformity determination, and a new conformity determination is not made within 12 months after that deadline, conformity on the plan/TIP will lapse. Refer to Chapter 1 for a complete discussion of plan/TIP requirements.

What Is a Conformity Lapse?

SAFEATEA-LU section 6011(e) Lapse of Conformity

This provision provides an additional 12 months after an applicable deadline is missed before the area enters a conformity lapse. It amends section 176(c) of the Clean Air Act (42 U.S.C. §7506(c)) by adding the following:

  1. Lapse of Conformity. - If a conformity determination required under this subsection for a transportation plan under section 134(i) of title 23, United States Code, or section 5303(i) of title 49, United States Code, or a transportation improvement program under section 134(j) of such title 23 or under section 5303(j) of such tile 49 is not made by the applicable deadline and such failure is not corrected by additional measures to either reduce motor vehicle emissions sufficient to demonstrate compliance with the requirements of this subsection within 12 months after such deadline or other measures sufficient to correct such failures, the transportation plan shall lapse.
  2. Lapse. - In this subsection the term 'lapse' means that the conformity determination for a transportation plan or transportation improvement program has expired, and thus there is no currently conforming transportation plan or transportation improvement program.

40 CFR §93.101, Definitions

Lapse means that the conformity determination for a transportation plan or TIP has expired, and thus there is no currently conforming transportation plan/TIP.

A conformity lapse occurs when an area fails to satisfy the frequency requirements (time frame for making a conformity determination). A lapse can also result from a SIP failure. A discussion on conformity lapses, causes and consequences is provided in Chapter 4.

Transportation planning statute requires that, in nonattainment and maintenance areas, the long-range (20-year) metropolitan transportation plan be updated every four years. Please see the SAFETEA-LU interim guidance related to planning for information on the four-year transportation plan. This schedule should also correspond with the four-year frequency requirement for a transportation conformity determination.

What Are the Major Requirements of the Transportation Conformity Process?

The major requirements of the transportation conformity process include:

Interagency Consultation

The interagency consultation process is the formal coordinating mechanism among transportation and air agency staffs and is central to the entire conformity process. Interagency consultation is discussed in detail in Chapter 2. The interagency consultation procedures apply to the development of the SIP, the transportation plan, the TIP, projects, and conformity determinations. Exhibit 2-1 in Chapter 2 shows the general requirements and typical roles and responsibilities of the agencies involved in transportation conformity. The interagency consultation process, which is tailored to each area, must be documented and incorporated into the SIP as a conformity SIP revision. A complete discussion of SIP requirements is provided in Section B.

Regional Emissions Analysis

Regional emissions analysis must be conducted in order to assess the regional impacts that transportation investments will have on emissions within the nonattainment or maintenance area. The latest EPA-approved emissions models must be used to estimate regional emissions. These estimates are derived from grams of pollutant per mile traveled and are based upon an estimation of vehicle miles traveled (VMT). The general requirements for conducting regional emissions analysis, which apply to all areas at all times, are discussed in detail in Chapter 5. Specific requirements for regional analysis that are based upon pollutant type and classification are discussed in Chapters 6 through 11.

Project Level Analysis

In nonattainment and maintenance areas, FHWA/FTA projects must be found to conform before they are adopted, accepted, approved or funded. The rule[14] also prohibits any FHWA/FTA project during the time frame of the transportation plan (or regional emissions analysis) from causing or contributing to any new localized CO or PM10 violations or the increasing the severity of existing violations. Transportation projects must conform to the following criteria:

If a project does not meet the above three criteria, the project cannot be found to conform. The project must be included in the plan/TIP and its regional emissions analysis according to the final design and scope. Section F discusses the project level analysis requirements and procedures for projects not from a conforming plan TIP.

Where Does Project Level Analysis Apply?

Project level hot spot analysis applies only to CO and PM10 nonattainment and maintenance areas and is based on quantitative analysis using applicable EPA approved air quality models or qualitative analysis. EPA issued PM2.5 and revised PM10 hot spot analyses requirements in March 2006. This Guide has not been updated to reflect those changes. Air quality dispersion models (e.g. CALINE4, CAL3QHC) are used to evaluate localized impacts (project level impacts) of carbon monoxide emissions. Nonattainment and maintenance areas may establish their own CO or PM10 protocols through the conformity SIP and interagency consultation processes.

Areas can establish their own procedures for quantitative analysis with EPA approval. In some cases, qualitative analysis may be used. Quantitative PM10 hot-spot analysis will not be required until EPA releases modeling guidance on this issue and announces it in the Federal Register. However, qualitative PM10 hotspot analysis is required prior to project-level approvals. The consultation process should be used to complete the qualitative analysis, and this analysis should be documented in the conformity determination.

For Which Projects Is Quantitative Analysis Required?

CO quantitative analysis is required[16] for the following, unless EPA approves alternative procedures:

Qualitative analysis is required for all other projects; the fact that no quantitative analysis is required does not mean that no analysis is required.

Transportation Control Measures

The rule defines transportation control measures (TCMs) as:

40 CFR §93.101, Definitions

Any measure that is specifically identified and committed to in the applicable implementation plan that is either one of the types listed in §108 of the CAA (See Exhibit 3-1), or any other measure for the purpose of reducing emissions or concentrations of air pollutants from transportation sources by reducing vehicle use or changing traffic flow or congestion conditions. Notwithstanding the above, vehicle technology-based, fuel-based, and maintenance-based measures which control the emissions from vehicles under fixed traffic conditions are not TCMs for the purposes of this subpart.

When are TCMs Included in a SIP?

Nonattainment and maintenance areas can include TCMs in the SIP as control measures to support the SIP's demonstration or as contingency measures[17]. If TCMs are included as control measures in the applicable SIP, they must be implemented and timely implementation demonstrated as part of the conformity determination. A detailed discussion of TCMs including criteria for enforceability, public participation, timely implementation and analysis techniques is discussed in Chapter 3.

When Do TCMs Need to Be Implemented?

If TCMs are included in the SIP, they must meet all SIP requirements (See Section B) and metropolitan planning requirements under 23 CFR 450 (See Chapter 1). Compliance with the SIP requirements will ensure that such TCMs can be implemented.

What Is Timely Implementation of TCMs?

In areas where TCMs are included in an approved SIP, the MPO, the State, and DOT must ensure that TCMs have funding consistent with the SIP schedule for timely implementation. This is required for a conformity determination and is incorporated into the conformity process to insure that TCMs are not postponed due to lack of a funding commitment. This can be a useful tool in reinforcing the linkages between SIPs and transportation plans and TIPs, and may require local, regional, and State transportation officials to make investment trade-offs between projects to ensure those TCMs included in approved SIPs are implemented. Chapter 3 discusses specific criteria for determining timely implementation of TCMs.

[1] CAA §176 (c); 42 U.S.C. §§7401 to 7671(q)
[2] ISTEA of 1991, Public Law 102-240, Dec. 18, 1991
[3] TEA-21, Public Law 105-178, June 9, 1998
[4] SAFETEA-LU, Public Law 109-56, August 10, 2005
[5] 40 CFR Parts 51 and 93
[6] 23 CFR Part 450, 49 CFR Part 613
[7] Any activity (funded, approved, permitted, etc.) undertaken by Federal agencies, other than the FHWA and the FTA, is governed by separate, general conformity regulations.
[8] 40 CFR §93.126
[9] In area that have missed a conformity deadline and are currently in the 12-month grace period before a conformity lapse will apply, projects must come from the previously conforming plan and TIP.
[10] 23 U.S.C. §§101-128, The National Highway System Designation Act of 1995, limited conformity to only nonattainment and maintenance areas
[11] Maintenance area means any geographic region of the United States previously designated nonattainment pursuant to the CAA Amendments of 1990 and subsequently redesignated to attainment subject to the requirement to develop a maintenance plan under section 175A of the CAA, as amended. 40 CFR §93.101.
[12] 40 CFR §93.104(e) - This provision was revised per SAFETEA-LU section 6011(a) and (b).
[13] See the planning and transportation conformity SAFETEA-LU interim guidance for a full discussion about the four year plan, TIP, and conformity determination.
[14] 40 CFR §§93.116, 93.123
[15] In area that have missed a conformity deadline and are currently in the 12-month grace period before a conformity lapse will apply, projects must come from the previously conforming plan and TIP
[16] 40 CFR §93.123(a) that "these procedures shall be used..., unless different procedures developed through the interagency consultation process required in 40 CFR §93.105 and approved by the EPA Regional Administrator are used."
[17] 42 U.S.C. §7502, CAA § 172 (c)(9)

Updated: 05/03/2013
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