Air Quality

Transportation conformity ("conformity") is a way to ensure that Federal funding and approval goes to those transportation activities that are consistent with Air Quality goals. Conformity applies to transportation plans, transportation improvement programs (TIPs), and projects funded or approved by the Federal Highway Administration (FHWA) or the Federal Transit Administration (FTA) in areas that do not meet or previously have not met air quality standards for ozone, carbon monoxide, particulate matter, or nitrogen dioxide.

These areas are known as "non-attainment areas" or "maintenance areas," respectively. A conformity determination demonstrates that the total emissions projected for a plan or program are within the emissions limits ("budgets") established by the air quality plan or State Implementation Plan (SIP), and that transportation control measures (TCMs) are implemented in a timely fashion.

Determining Conformity
Regional emissions are estimated based on highway and transit usage according to transportation plans and TIPs. The projected emissions for the plan and TIP must not exceed the emissions limits (or "budgets") established by the SIP. Also, the MPO is required to demonstrate that TCMs are implemented in a timely fashion.

The Decision Process
A formal interagency consultation process involving the Environmental Protection Agency (EPA), FHWA, FTA and State and local transportation and air quality agencies is required in developing SIPs, TIPs, and transportation plans, and in making conformity determinations. Metropolitan Planning Organization (MPO) policy boards make initial conformity determinations in metropolitan areas, while State Departments of Transportation (DOT) usually do so in areas outside of MPOs. Conformity determinations must also be made at the Federal level by FHWA/FTA. These determinations must be made at least every three years, or when transportation plans or TIPs are updated.

Conformity analysis is made available to the public as part of the MPO and/or State DOT planning processes. MPOs are required to make transportation plans, TIPs, and conformity determinations available to the public, accept and respond to public comments, and provide adequate notice of relevant public meetings. Project sponsors must also include appropriate public involvement during project development.

Emissions Budget
The SIP places limits on emissions of each pollutant for each source type (mobile, stationary and area sources). Projected emissions from highway and transit usage must be less than or equal to the emissions limits for on-road mobile vehicles that are established by the SIP. These emissions limits for motor vehicle emissions sources are called "budgets." Budgets are developed as part of the air quality planning process by State air quality/environmental agencies, and approved by EPA. Transportation agencies participate in this process.

Transportation Control Measures (TCMs)
Areas can include TCMs in their SIPs. TCMs are specific programs designed to reduce emissions from transportation sources by reducing vehicle use or changing traffic flow or congestion conditions.

Programs for improving public transit include:

• developing high occupancy vehicle (HOV) facilities
• ordinances to promote non-motor vehicle travel
• transit improvements
• signal timing
• bicycle and pedestrian facilities
• land use planning

North Carolina's Congestion Mitigation & Air Quality Program

Congestion Mitigation & Air Quality (CMAQ) is a Federal program that funds transportation projects and programs in air quality nonattainment and maintenance areas to help achieve and maintain national standards for air quality pollutants.  In North Carolina, NCDOT serves as the administrator for this program. 

The North Carolina Department of Transportation modified the Congestion Mitigation & Air Quality (CMAQ) Improvement Program for North Carolina in 2008 and revised guidance for requesting new CMAQ project may be accessed below: 

• Project Selection & Programming for Fiscal Years 2013 & Beyond.
  (Updated 8/10/2009)

Summary sheets detailing CMAQ information for each eligible MPO/RPO and for statewide projects may be accessed here.  This information includes the following: 

• Listing of all CMAQ projects programmed since the initial 2004 Call for Projects by MPO/RPO and for statewide projects; (Updated 6/23/2009)
• Target funding available to each MPO/RPO and the target statewide allocation for programming under the Project Selection & Programming for FFY 2013 – 2017.
  (Updated 6/23/2009)

Additional CMAQ Information

• Federal CMAQ Guidance

• New Direction of CMAQ in North Carolina (Final Version) (200 KB)

• CMAQ Project Application (50 KB)  (Updated 6/15/2009)

  • Please note – an editable version of the application may be accessed at the NCDOT Forms website by searching for “CMAQ”

• Sample Resolution Endorsing Candidate CMAQ Project Proposals

• CMAQ Program Implementation Project Manager’s Guide (1.4 MB)

• Summary of CMAQ Projects Funded Since 2004

• 2006 – 2012 STIP

• 2009 – 2015 STIP

• CMAQ Vendor Registration Form (20 KB)
• CMAQ Information Session Handouts (Added 27/7/2009) (220 KB)

Emissions Calculations Assistance

• Emissions Calculations Assistance (41KB)
• Mobile 6 Classifications (60KB)
• Rural County VMT Reductions Spreadsheets (42 KB)
• Urban County  VMT Reductions Spreadsheets (39 KB)
• Emissions Factors for CMAQ Applicants (Zipped File) (121 KB)
• AQ Analysis Methodologies for Transportation Control Measures Course  Information  (Added 27/7/2009)   (7.4 MB)
• AQ Emissions Analysis Methodologies for Diesel Idling Webinar Information (Added 27/7/2009) (290 KB)