Statewide Conformity Working Group

Transportation Conformity

"Conformity" is a requirement of the Federal Clean Air Act (Section 176(c), at 42 U.S.C. 7506 (PDF)(c)), to ensure that federal actions are consistent with the State Implementation Plan ("SIP") to achieve and maintain Federal air quality standards. "Transportation Conformity" requirements for highway and transit projects are defined by U.S. Environmental Protection Agency (EPA) regulations in 40 CFR 93 Subpart A, US EPA and US DOT (FHWA) guidance, and local consultation procedures set up by Metropolitan Planning Organizations and Air Pollution Control Districts. The map and table below illustrate the areas that are subject to Transportation Conformity requirements in California in 2014. For other types of federal actions, not related directly to highways and transit, the conformity process is governed by 40 CFR 93 Subpart B (General Conformity).

Conformity requirements apply only in areas that are designated nonattainment, or attainment with a "Maintenance SIP" as defined in 42 U.S.C. 7505a (PDF), by the US EPA. It applies only for the pollutants that trigger those designations, and analysis requirements only apply to those pollutants. It is therefore possible for some conformity procedures (for instance, project-level hot spot requirements) to be inapplicable if the area is attainment/unclassifiable for the pollutants triggering them, even though the area is subject to conformity requirements in general. Conformity requirements do not apply at all if an area is attainment/unclassifiable for all federal air quality standards.

Map of Areas Subject to Conformity Requirements (PDF)

Or view a Table of Areas Subject to Transportation Conformity Requirements (PDF)

How to Participate

The Statewide Conformity Working Group is a coordinating group for discussion and interagency agreement about transportation-related air quality and Federal Clean Air Act conformity issues in California. The public is welcome to participate, and there is a time on the agenda for public comment regarding issues not otherwise on the agenda. Actions taken by the group are not regulations; rather, they are informational in nature, or are agreements regarding procedures and interpretation of the transportation conformity regulations to be used by transportation agencies and project proponents.

Statewide Conformity Working Group meetings are generally held twice a year by teleconference. Teleconference access to the meeting is provided through regional call centers, usually located at offices of regional transportation planning agencies, air pollution control or air quality management districts, or Caltrans. Individual call-in access to the teleconference may also be provided; please contact the Working Group chair to arrange it.

The meeting and call center locations, with site contact information, are noted on the printable copy of the agenda for each meeting. Contact information for the call centers is also provided on the agenda.

Caltrans maintains an electronic mail list to forward announcements and other information to the working group. For network security reasons, the list archives are only available to list members. Go to the mailing list page to sign up.

Interagency Consultation in General

The Federal Clean Air Act "conformity" process includes an Interagency Consultation process that involves Federal Agencies (US EPA, Federal Highway Administration, and Federal Transit Administration), the State transportation agency (Caltrans), the State air quality management agency (California Air Resources Board), and regional transportation planning and air quality agencies (Metropolitan Planning Organizations, Air Pollution Control/Air Quality Management districts, and in some California cases Regional Transportation Planning Agencies). Transit and other transportation service providers are also involved.

Most Interagency Consultation occurs at the regional level. An Interagency Consultation group for the conformity process exists in all Federal nonattainment areas. In most cases, the Transportation Planning Agency (Metropolitan Planning Organization - MPO) is the lead agency for the consultation process.

The Statewide Conformity Working Group coordinates and considers issues of a statewide nature. The Group normally meets twice a year: usually in March and September or October. Meetings are held by teleconference using regional call-in meeting centers to minimize travel.

Statewide Conformity Working Group meetings, as with regional Interagency Consultation meetings in the Transportation Conformity process, are open to the public. Members of the public who wish to attend should either call in to the teleconference using the number announced here or arrange with regional teleconference coordinators for attendance. Regional teleconference centers and the agenda are usually posted at this site 1-2 weeks before the meeting.

The Statewide Conformity working group has been meeting since the mid-1990's. Formal Interagency Consultation requirements for conformity purposes came from the 1990 Federal Clean Air Act Amendments and the EPA Conformity Regulations at 40 CFR Part 93. The group was chaired initially by Caltrans, then by the California Air Resources Board until 2003. The Federal Highway Administration, California Division chaired the group in 2003, and US EPA, Region IX chaired the group in 2004. The group is currently chaired by the California Department of Transportation (Caltrans), Transportation Planning Division, and suggestions or requests for agenda items should be sent to a Caltrans conformity staff member in the contact list below.

2018 Meetings

2017 Meetings

Hot Topics


This web site is maintained by the California Department of Transportation, Division of Transportation Planning, Office of Regional and Interagency Planning, Air Quality Coordination Branch. For web site-related issues, please contact one of the Caltrans staff below:

Conformity Working Group Chair:

Lucas Sanchez
Department of Transportation
Air Quality Specialist
(916) 653-2023

Caltrans Headquarters Conformity Staff:

Rodney Tavitas
Air Quality and Conformity Coordination
(916) 653-1069