Our Work
- Connect SoCal
- Inclusion, Diversity, Equity & Awareness
- Programs & Projects
- Housing
- Economy & Demography
- Federal & State Compliance
- Sustainable Development and Resilient Communities
- Transportation
- Active Transportation
- Aviation Program
- Regional Pilot Initiatives Program
- The Future Communities Initiative
- Transportation Demand Management
- Transit Program
- FreightWorks
- Passenger Rail Program
- Corridor Planning
- Transportation Safety
- Transportation Finance
- Intelligent Transportation Systems
- Southern California Transportation Study
- Local Resources
- Funding & Programming
- Legislation & Advocacy
- Publications & Reports
Transportation Conformity Regulations
Transportation conformity is required under the federal Clean Air Act Section 176© to ensure federally supported transportation activities conform to or are consistent with the purpose of the applicable air quality management plan or State Implementation Plan (SIP). The Transportation Conformity Regulations are found in 40 Code of Federal Regulation (CFR) Part 93. Provisions related to conformity SIPs are found in 40 CFR Section 51.390. SCAG’s Transportation Conformity Working Group serves as the primary forum for interagency consultation on all matters related to both regional and project-level transportation conformity to comply with federal transportation and air quality planning requirements and improve air quality in Southern California.
The Transportation Conformity Working Group (TCWG) serves as the primary forum for interagency consultation on all matters related to both regional and project-level transportation conformity to comply with federal transportation and air quality planning requirements in the six-county SCAG region. The TCWG consists of staff representatives from FHWA, FTA, U.S. EPA, Caltrans Headquarters, Caltrans Districts, CARB, CTCs, air districts, and transit operators in the SCAG region. The group meets monthly on the fourth Tuesday of the month.
For particulate matter (PM) hot spot interagency consultation, SCAG staff facilitates the review and determination by TCWG as to whether a project is a Project of Air Quality Concern (POAQC), as well as the review and approval of modeling protocols and subsequent quantitative PM hot spot analysis if and after a project has been determined to be a POAQC by TCWG.
TCWG discusses, reviews, and makes a determination as to whether a project is POAQC based on project information included in the PM Hot Spot Interagency Review Form. The form applies to all project-level conformity review cases, as the lead agency requests TCWG’s concurrence that their project is not a POAQC. Projects exempt from conformity analysis are also determined through review of the Caltrans Conformity Streamlining Exemption Form.
If you need to submit a form to TCWG for interagency consultation, please coordinate with the state and/or local project representative for your project’s county. Contact information for project-level conformity representations can be found in the “Project-Level Conformity Contact List.”
The submissions below include all of the PM hot spot interagency review forms, qualitative analyses, and quantitative analyses that have been or will be reviewed by the TCWG. The titles include the FTIP Project ID, where available, and any determinations made by the TCWG (e.g., Project of Air Quality Concern (POAQC)).
Instructions for PM Hotspot Interagency Review
Project-Level Conformity Contact List
PM Hot-Spot Interagency Review Form Template
Caltrans Conformity Streamlining Exemption Form
Federal approvals of regional transportation conformity determinations for Regional Transportation Plan (RTP)/Federal Transportation Improvement Program (FTIP) and amendments from Federal Highway Administration/Federal Transit Administration (FHWA/FTA) may be provided electronically through the California Transportation Improvement Program System database, including federal approval date and federal approval letters. Federal approval letters will continue to be produced for project-level conformity determinations.
Transportation Control Measures (TCMs) are identified by air quality management plans and implementation plans to reduce emissions or concentrations of air pollutants from transportation sources by reducing vehicle use, changing traffic flow, or congestion conditions. SCAG works closely with the CTCs and Caltrans to ensure timely implementation of committed TCM projects in the region. Substitution of individual TCMs follows the process specified in the federal Clean Air Act (CAA) section 176(c). Section 176© of the CAA allows for the substitution of individual TCMs if certain conditions are met. The CTCs and/or project sponsors notify SCAG when a TCM project cannot be delivered or will be significantly delayed. SCAG and the CTCs identify and evaluate possible replacement measures for individual substitutions, with consultation from the Transportation Conformity Working Group (TCWG), which includes members from all affected jurisdictions, federal, state and/or local air quality agencies, and transportation agencies.
Air quality plans and corresponding documents are maintained and available on the California Air Resources Board website.
TCM Substitutions
- 2022
Orange County Transportation Authority (OCTA) Transportation Control Measure (TCM) Substitution Report (FTIP IDs ORA130099 & ORA030612)
Orange County Transportation Authority (OCTA) Transportation Control Measure (TCM) Substitution Report (FTIP IDs 10254, ORA050 & ORA051)
- 2018
Draft Orange County Transportation Authority (OCTA) Transportation Control Measure (TCM) Substitution Report for Public Review
- 2016
OCTA TCM Substitution
- 2015
Los Angeles County Metropolitan Transportation Authority (Metro), Riverside County Transportation Commission (RCTC), and San Bernardino Associated Governments (SANBAG) TCM Substitutions
- 2013
Replacement of a Bus Purchase Project with Traffic Signal Sychronization Projects in Orange County (OCTA)
- 2010
State Route 60 HOV Lane Conversion of Moreno Valley, Riverside County (Caltrans)
Replacement of Bus Rapid Transit (BRT) Projects with Signal Sychronization Projects in Orange County (OCTA)
