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Transportation Conformity Reference Guide

Section C: General Requirements
Chapter 3 Transportation Control Measures

Description of Transportation Control Measures
When Are TCMs Included in SIPs?
Criteria for Transportation Control Measures to Be Included in SIPs
Timely Implementation of Transportation Control Measures in SIPs
Which TCMs Are Required to Meet the Timely Implementation Test?
Criteria for Demonstrating Timely Implementation of TCMs in Transportation Plans
Criteria for Demonstrating Timely Implementation of TCMs in TIPs
Criteria for Demonstrating Timely Implementation of TCMs for Projects Not From a Conforming Transportation Plan/TIP
Substituting Transportation Control Measures
Emissions Credits for TCMs in Regional Conformity Analysis
Status of TCMs During a Conformity Lapse
Advancing New TCMs During a Conformity Lapse
Interim Transportation Plan and TIP Requirements
TCMs in a Previously Conforming Transportation Plan and TIP
New TCMs Not From a Previously Conforming Transportation Plan and TIP
Voluntary Mobile Source Emission Reduction Programs (VMEP)
Questions and Answers

Exhibit 3-1: Transportation Control Measures

This chapter provides information on the requirements for transportation control measures (TCMs). TCMs include a wide variety of measures used to reduce motor vehicle emissions, primarily by reducing the total amount of vehicle miles of travel in an area. Examples of traditional TCMs include: transit, ridesharing arrangements, telecommuting and parking management.

Description of Transportation Control Measures

Transportation control measures are defined in the transportation conformity rule as follows:

40 CFR §93.101, Definitions

Transportation control measure (TCM) is 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, 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 congested conditions. Notwithstanding the first sentence in this definition, vehicle technology-based, fuel-based, and maintenance-based measures which control the emissions from vehicles under fixed traffic conditions are not TCMs for the purpose of this subpart.

The CAA included a list of TCMs (Exhibit 3-1) that can be considered, along with other transportation measures for inclusion in SIPs. As shown in the Exhibit, these TCMs include a host of transportation demand management programs as well as public transit, high occupancy vehicle lanes and other pedestrian and bicycling programs; all of which are directed at reducing automobile travel and increasing vehicle occupancy levels.

Exhibit 3-1
Transportation Control Measures
CAA §108(f)(1)(A), 42 U.S.C. §7408(f)(1)

  1. programs for improved public transit;
  2. restriction of certain roads or lanes to, or construction of such roads or lanes for use by, passenger buses or high-occupancy vehicles (HOV);
  3. employer-based transportation management plans, including incentives;
  4. trip-reduction ordinances;
  5. traffic flow improvement programs that achieve emissions reductions;
  6. fringe and transportation corridor parking facilities serving multiple-occupancy vehicle programs or transit service;
  7. programs to limit or restrict vehicle use in downtown areas or other areas of emissions concentration particularly during periods of peak use;
  8. programs for the provision of all forms of high-occupancy, shared-ride services;
  9. programs to limit portions of road surfaces or certain sections of the metropolitan area to the use of non-motorized vehicles or pedestrian use, both as to time and place;
  10. programs for secure bicycle storage facilities and other facilities, including bicycle lanes, for the convenience and protection of bicyclists, in both public and private areas;
  11. programs to control extended idling of vehicles;
  12. programs to reduce motor vehicle emissions which are caused by extreme cold-start conditions;
  13. employer-sponsored programs to permit flexible work schedules;
  14. programs and ordinances to facilitate non-automobile travel, provision and utilization of mass transit, and to generally reduce the need for single-occupant vehicle travel, as part of transportation planning and development efforts of a locality, including programs and ordinances applicable to new shopping centers, special events, and other centers of vehicle activity;
  15. programs for new construction and major reconstruction of paths, tracks, or areas solely for use by pedestrian or other non-motorized means of transportation when economically feasible and in the public interest. For purposes of this clause, the Administrator shall also consult with the Secretary of the Interior; and
  16. programs to encourage the voluntary removal from use and the marketplace of pre-1980 model year light duty vehicles and pre-1980 model light duty trucks. *

*Note: Excluded from CMAQ Funding under Title 23 U.S.C. Section 149

When are TCMs Included in SIPs?

Nonattainment and maintenance areas can include TCMs in SIPs as control measures to support the SIPs demonstration or as contingency measures. The CAA required that contingency measures be developed in moderate and above 1-hour ozone nonattainment area 15% SIPs and in moderate (>12.7 ppm) carbon monoxide area SIPs.

Criteria for Transportation Control Measures to Be Included in SIPs

TCMs must satisfy the following eight criteria before EPA will consider them for approval in a SIP[1]:

  1. A complete description of the measure and its estimated emissions reduction benefits,
  2. Evidence that the measure was properly adopted by a jurisdiction with legal authority to commit to and execute the measure,
  3. Evidence that funding has been (or will be) obligated to implement the measure,
  4. Evidence that all necessary approvals have been obtained from all appropriate government agencies (including MPOs and State transportation departments, if applicable),
  5. Evidence that a complete schedule to plan, implement, and enforce the measure has been adopted by the implementing agency or agencies,
  6. A description of the monitoring program to assess the measures' effectiveness and to allow for necessary in-place corrections or alterations,
  7. Governor's approval of the SIP, and
  8. Public hearing (as part of the SIP approval process).

Timely Implementation of Transportation Control Measures in SIPs

The transportation conformity rule and the Clean Air Act require that TCMs in approved SIPs be implemented in a timely manner according to the schedules in the SIP. The intent of this provision is to ensure that TCMs which are eligible for Federal funding receive priority for funding, and that the SIP schedules and commitments are enforced. If a nonattainment or maintenance area cannot determine that TCMs are meeting the timely implementation requirement, the plan, TIP or project (not from a plan/TIP) does not conform.

Note, this requirement is not dependent on what type of SIP, pollutant, or standard for which the approved TCM was established. Therefore, TCMs in approved SIPs for the 1-hour ozone standard must still be implemented in a timely manner even though the 1-hour ozone standard has been revoked, unless those TCMs are removed from the SIP through the SIP Process (69 FR 40013, July 1, 2004).

CAA §176(c)(2)(B), 42 U.S.C. §7506(c)(2)(B)

No metropolitan planning organization or other recipient of funds under title 23, United States Code, or the Urban Mass Transportation Act shall adopt or approve a transportation improvement program of projects until it determined that such program provides for timely implementation of transportation control measures consistent with schedule included in the application implementation plan.

40 CFR §93.113

(a) The transportation plan, TIP, or any FHWA/FTA project which is not from a conforming plan/TIP must provide for the timely implementation of TCMs from the applicable implementation plan.

58 FR 62197, November 24, 1993

EPA believes that the determination of "timely implementation" should focus on the prospective schedule for TCM implementation, and all past delays should be irrelevant. Therefore, it is permissible for the plan/TIP to project completion of a TCM implementation milestone which is later than the SIP schedule if the lateness is due to delays which have already occurred, or due to the time reasonably required to complete remaining essential steps (such as preparation of a NEPA document, design, work, right-of-way acquisition, Federal permits, construction, etc.). It is also permissible to allow time for obtaining State or local permits if the project has not yet advanced to the point where a permit could have been applied for.

However, where implementation milestones have been missed or are projected to be missed, agencies must demonstrate that maximum priority is being given to TCM implementation. All possible actions must be taken to shorten the time periods necessary to complete essential steps in TCM implementation-for example, by increasing the funding rate-even though the timing of other projects may be affected. It is not permissible to have prospective discrepancies with the SIP's TCM implementation schedule due to lack of programming funding in the TIP, lack of commitment to the project by sponsoring agency, unreasonably long periods to complete future work due to lack of staff or other agency resources, lack of approval or consent by local government bodies, or failure to have applied for a permit where necessary work preliminary to such application has been completed. However, where statewide and metropolitan funding resources and planning and management capabilities are fully consumed with responding to damage from natural disasters, civil unrest, or terrorist acts, TCM implementation can be determined to be timely without regard to the above, provided reasonable efforts are being made. The burden of proof will be on the agencies making conformity determinations to demonstrate that the amount of time to complete remaining implementation steps will not exceed that specified in the SIP without good cause, and that where possible, steps will be completed more rapidly than assumed in the SIP in order to make up lost time.

Which TCMs Are Required to Meet the Timely Implementation Test?

The conformity rule requires those TCMs that are included in an EPA-approved SIP and that are eligible for Federal funding are subject to the timely implementation requirement.

58 FR 62211, November 24, 1993

...since (transportation) plans/TIPs can at most "provide for" only those projects which are eligible for Federal funding, it is reasonable to define those TCMs required to be implemented by Clean Air Act section 176 (c)(2)(B) to be only those SIP TCMs that are eligible for Federal funding.

As part of the interagency consultation process (see Chapter 2), a determination must be made that when TCMs included in an approved SIP have been delayed in the past or are currently behind schedule, all obstacles to implementation have been identified and are being overcome. In addition, U.S. DOT must, in approving a conformity determination, find that priority is being given to TCMs included in approved SIPs.

The criteria and procedures for determining timely implementation are different for plans and TIPs and projects not from a conforming plan/TIP and are discussed below.

Criteria for Demonstrating Timely Implementation of TCMs in Transportation Plans

Timely implementation of TCMs for transportation plans can be demonstrated by showing:

40 CFR §93.113(b)(1-2)

  1. The transportation plan, in describing the envisioned future transportation system, provides for the timely completion or implementation of all TCMs in the applicable implementation plan which are eligible for funding under title 23 U.S.C. or the Federal Transit Laws, consistent with schedules included in the applicable implementation plan.
  2. Nothing in the transportation plan interferes with the implementation of any TCM in the applicable implementation plan.

Criteria for Demonstrating Timely Implementation of TCMs in TIPs

To demonstrate timely implementation of TCMs for TIPs, the following criteria must be met:

40 CFR §93.113(c)(1-3)

  1. An examination of the specific steps and funding source(s) needed to fully implement each TCM indicates that TCMs which are eligible for funding under title 23 U.S.C. or the Federal Transit Laws are on or ahead of the schedule established in the applicable implementation plan, or if such TCMs are behind the schedule established in the applicable implementation plan, the MPO and DOT have determined that past obstacles to implementation of the TCMs have been identified and have been or are being overcome, and that all State and local agencies with influence over approvals or funding for TCMs are giving maximum priority to approval or funding of TCMs over other projects within their control, including projects in locations outside the nonattainment or maintenance area.
  2. If TCMs in the applicable implementation plan have previously been programmed for Federal funding but the funds have not been obligated and the TCMs are behind the schedule in the implementation plan, then the TIP cannot be found to conform if the funds intended for those TCMs are reallocated to projects in the TIP other than TCMs, or if there are no other TCMs in the TIP, if the funds are reallocated to projects in the TIP other than projects which are eligible for Federal funding intended for air quality improvement projects, e.g. the Congestion Mitigation and Air Quality Improvement Program.
  3. Nothing in the TIP may interfere with the implementation of any TCM in the applicable implementation plan.

Criteria for Demonstrating Timely Implementation of TCMs for Projects Not From a Conforming Transportation Plan/TIP

40 CFR §93.113(d)

  1. For FHWA/FTA projects which are not from a conforming transportation plan/TIP, this criteria is satisfied if the project does not interfere with the implementation of any TCM in the applicable implementation plan.

Substituting Transportation Control Measures

SAFETEA-LU section 6011(d) Substitution of Transportation Control Measures

This provision provides nonattainment and maintenance areas with a streamlined process for either replacing TCMs in approved SIPs with alternate TCMs or for adding TCMs to their approved SIPs. It amends section 176(c) of the Clean Air Act (42 U.S.C. 7506(c)) by adding the following:

  1. Substitution of Transportation Control Measures
    1. In General. - Transportation control measures that are specified in an implementation plan may be replaced or added to the implementation plan with alternate or additional transportation control measures
      1. If the substitute measures achieve equivalent or greater emissions reductions than the control measure to be replaced, as demonstrated with an emission impact analysis that is consistent with the current methodology used for evaluating the replaced control measure in the implementation plan;
      2. If the substitute control measures are implemented
        1. In accordance with a schedule that is consistent with the schedule provided for control measures in the implementation plan; or
        2. If the implementation plan date for implementation of the control measure to be replaces has passed, as soon as practicable after the implementation plan date but not later than the date on which emission reductions are necessary to achieve the purpose of the implementation plan;
      3. If the substitute and additional control measures are accompanied with evidence of adequate personnel and funding and authority under State or local law to implement, monitor, and enforce the control measures;
      4. If the substitute and additional control measures were developed through a collaborative process that included
        1. Participation by representatives of all affected jurisdictions (including local air pollution control agencies, the State air pollution control agency, and State and local transportation agencies);
        2. Consultation with the Administrator; and
        3. Reasonable public notice and opportunity for comment; and
      5. If the metropolitan planning organization, State air pollution control agency, and the Administrator concur with the equivalency of the substitute or additional control measures.
    2. Adoption.
      1. Concurrence by the metropolitan planning organization, State air pollution control agency and the Administrator as required by subparagraph (A)(v) shall constitute adoption of the substitute or additional control measures so long as the requirements of subparagraph (A)(i), (A)(ii), (A)(iii) and (A)(iv) are met.
      2. Once adopted, the substitute or additional control measures become, by operation of law, part of the state implementation plan and become federally enforceable.
      3. Within 90 days of its concurrence under subparagraph (A)(v), the State air pollution control agency shall submit the substitute or additional control measure to the Administrator for incorporation in the codification of the applicable implementation plan. Notwithstanding any other provision of this Act, no additional State process shall be necessary to support such revision to the applicable plan.
    3. No Requirement For Express Permission. - The substitution or addition of a transportation control measure in accordance with this paragraph and the funding or approval of such a control measure shall not be contingent on the existence of any provision in the applicable implementation plan that expressly permits such a substitution or addition.
    4. No Requirement for New Conformity Determination. - The substitution or addition of a transportation control measure in accordance with this paragraph shall not require
      1. A new conformity determination for the transportation plan; or
      2. A revision of the implementation plan.
    5. Continuation of Control Measures Being Replaced. - A control measure that is being replaced by a substitute control measure under this paragraph shall remain in effect until the substitute control measure is adopted by the State pursuant to subparagraph (B).
    6. Effect of Adoption. - Adoption of a substitute control measure shall constitute rescission of the previously applicable control measure.

    The SAFETEA-LU provision superseded EPA's April 7, 2004, policy guidance that describes the adoption and use of transportation control measure (TCM) substitution mechanisms.

Emissions Credits for TCMs in Regional Conformity Analysis

Emission credit can be claimed for TCMs in approved SIPs in the regional conformity analysis under the following circumstances (please refer to Chapter 5 and Section D for additional information on regional conformity analysis and analysis of TCMs):

Status of TCMs During a Conformity Lapse

In accordance with the transportation conformity rule[2], TCMs in an approved SIP can proceed in the event of a conformity lapse, provided they have been coordinated through the air quality/transportation planning[3] process. This allows for the timely implementation of TCMs that are included in an approved SIP even in the event of a conformity lapse.

62 FR 43781, August 15, 1997

...The second set of amendments also allowed any transportation control measure (TCM) from an approved SIP to proceed during a conformity lapse, although EPA stated that it did not intend to approve SIPs containing TCMs that have not been coordinated through the transportation planning process, as required by 23 CFR part 450 and 49 CFR part 613. The Clean Air Act and the Intermodal Surface Transportation Efficiency Act require that an integrated transportation/air quality planning process be used to identify effective TCMs and ensure their funding sources.

Advancing new TCMs During a Conformity Lapse

In accordance with the National Memorandum of Understanding between the U.S. Department of Transportation and the U.S. Environmental Protection Agency for transportation conformity (See Appendix C), which was executed in April 2000, the following procedures apply for areas that wish to advance new TCMs during a conformity lapse.

Interim Transportation Plan and TIP Requirements

Federal transportation law requires that projects must be in a plan and TIP to receive Title 23 and Title 49 funds. Therefore, in the event of a conformity lapse, an MPO must create an Interim Plan and TIP for any projects to be federally-funded and approved during the lapse, including exempt projects and transportation control measures (TCMs). The Interim Plan and TIP must be developed in a manner consistent with the metropolitan planning regulations (23 U.S.C. 134), particularly these criteria:

  1. The Interim Plan and TIP must be developed based on previous planning assumptions and goals; appropriately adjusted for currently available projections for population growth, economic activity and other relevant data.
  2. The Interim Plan and TIP must be developed with public involvement consistent with the normal transportation plan and program development processes.
  3. The Interim Plan and TIP must satisfy the Title 23 and 49 requirements for financial planning and constraint, and, as appropriate, for congestion management systems.
  4. The Interim TIP must be approved by the MPO and the Governor (or the Governor's designee).

TCMs in a Previously Conforming Transportation Plan and TIP

Projects in the previously conforming transportation plan must be included in the Interim Plan and TIP if State and local agencies intend to request EPA to approve them into the SIP as new TCMs (as defined in 40 CFR 93.101 of the transportation conformity rule which includes TCMs defined by Section 108(f)(1)(A) of the Clean Air Act (CAA)) and if they have emission reductions benefits. The TCMs cannot proceed during a conformity lapse until they are contained in an EPA approved SIP with identifiable emission reduction benefits. States may, but are not required to, apply the identified emission reduction benefits directly as SIP credits in control strategy SIPs and maintenance plans. Future conformity analyses may reflect the emission reduction benefits identified in the SIP for regionally significant TCMs; such emission reduction benefits must be adjusted to reflect latest planning assumptions (40 CFR 93.110) at the time of the conformity analysis, and as appropriate to meet the requirements of 40 CFR 93.122. For non-regionally significant TCMs, the emission reduction benefits identified in the SIP may be used for future conformity analyses; such emission reduction benefits must be adjusted to reflect latest planning assumptions (40 CFR 93.110) at the time of the conformity analysis, and as appropriate to meet the requirements of 40 CFR 93.122(a).

New TCMs Not From a Previously Conforming Transportation Plan and TIP

New TCMs, not included in a previously conforming Plan and TIP, may be advanced during a conformity lapse provided they are included in an Interim Plan and TIP that meet the criteria above and are contained in an EPA approved SIP with identified emission reduction benefits.

They must also meet the following criteria:

  1. The new TCM(s) must be accompanied by evidence of adequate personnel, and funding and authority under state or local law to implement, monitor and enforce the TCM(s);

  2. The new TCM(s) must be developed through a collaborative process that includes participation by all affected jurisdictions and agencies (e.g., state and local air pollution control agencies and state and local transportation agencies); consultation with EPA; and reasonable notice and opportunity for public comment;

  3. They must be described at a level of detail and analysis appropriate to their overall level of investment and complexity (i.e., regionally significant TCMs must be described and analyzed at a significant level of detail, appropriate to the scale of the project and adequate for emissions analysis purposes, while non-regionally significant TCMs may be presented in much less detail).

  4. If regionally significant (as defined in 40 CFR 93.101), they must be shown to yield reduced emissions on a regional basis compared to regional emissions without the TCMs for the analysis period. The analysis period will include the SIPs milestone year(s) (if relevant), and the year the TCMs are open to traffic or become operational (if the TCM's schedule is outside the SIP's time frame). Transportation and air quality planners must consult with each other on the methodologies used to estimate the transportation and air quality benefits of the regionally significant projects. Off-model analysis techniques must be used, to the extent possible; to quantify emissions benefits for non-regionally significant TCMs. Appropriate techniques will be decided through interagency consultation.

  5. The MPO, the state air pollution control agency and EPA must concur on the addition of the new TCM to the SIP. TCMs cannot proceed during a lapse until they are contained in an EPA approved SIP with identifiable emission reduction benefits. States may, but are not required to, apply the identified emission reduction benefits directly as SIP credits in control strategy SIPs and maintenance plans. Future conformity analyses may reflect the emission reduction benefits identified in the SIP for regionally significant TCMs; such emission reduction benefits must be adjusted to reflect latest planning assumptions (40 CFR 93.110) at the time of the conformity analysis, and as appropriate to meet the requirements of 40 CFR 93.122. For non-regionally significant TCMs, the emission reduction benefits identified in the SIP may be used for future conformity analyses; such emission reduction benefits must be adjusted to reflect latest planning assumptions (40 CFR 93.110) at the time of the conformity analysis, and as appropriate to meet the requirements of 40 CFR 93.122(a).

Under this scenario, the State and MPO may advance any TCMs defined by 40 CFR 93.101 of the transportation conformity rule (which includes TCMs defined by Section 108(f)(1)(A) of the CAA).

Voluntary Mobile Source Emission Reduction Programs (VMEP)

In October 1997, EPA issued Guidance on Incorporating Voluntary Mobile Source Emissions Reduction Programs (VMEPs) in State Implementation Plans. The VMEP guidance will allow areas to implement and claim SIP credit for these programs for the first time. VMEPs encompass many mobile source control measures; some of these are TCMs. The guidance document discusses how voluntary measures can be incorporated into the SIP and receive emissions reduction credit. EPA discusses the terms and conditions for establishing and implementing VMEPs and recognizes the potential that VMEPs have to contribute, in a cost-effective manner, to needed emissions reductions.

EPA's guidance establishes a cap on the SIP credit allowed for VMEPs to 3% of the total projected future year emissions reductions required to attain the NAAQS. EPA notes that the emissions reduction potential of VMEPs is generally a fraction of one ton per day.

Questions and Answers

(From EPA's February 15, 1994 Memoranda on Transportation Conformity Q & As)

Must conformity determinations demonstrate timely implementation of TCMs which are included in a submitted SIP, but are not included in the existing SIP approved by EPA?

Conformity determinations must demonstrate timely implementation of only those TCMs which are included in a SIP which has been approved by EPA. However, the transportation community should consider whether it would be necessary to begin implementation of TCMs in a submitted SIP before the SIP is approved, in order to meet the implementation deadline in the SIP once the SIP is approved.

Is street sweeping for PM-10 control a TCM for which timely implementation must be demonstrated, if it is included in an approved SIP?

No, EPA does not believe that street sweeping is a TCM.


[1] Transportation Control Measures: State Implementation Plan Guidance, U.S. EPA, 450/2-89-020, Sept., 1990
[2] 40 CFR §§93.114(b), 93.115(d)
[3] 23 CFR §450, 49 CFR Part 613


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