California Air Resources Board

Southern California Association of Governments (SCAG) is the largest MPO in California, covering six counties and 191 cities in the Southern California region. It is the transportation planning agency responsible for developing and implementing the long-range regional transportation plan, known as the Regional Transportation Plan/Sustainable Communities Strategy (RTP/SCS).

The 2020 RTP/SCS continues to emphasize the key land use and transportation strategies in the first SCS that support a more sustainable future for the SCAG region. SCAG anticipates new growth will occur within existing urban boundaries with higher density development instead of sprawling outward. The 2020 SCS continues on the course set by the 2016 SCS to direct transportation investments within existing urbanized areas to support a more compact urban form. It includes an extensive regional bus and bus rapid transit (BRT) system, improved commuter and light rail service, an expanded regional bicycle network, improved pedestrian infrastructure, dedicated highway lanes for carpool and express buses, and several transportation demand management programs that reduce the number of vehicle trips.

Draft 2024 RTP/SCS (Connect SoCal)

• CARB staff's First Comment Letter and attachment on SCAG's Draft Technical Methodology to Estimate Greenhouse Gas Emission for Connect SoCal (August 2023)
• CARB staff's Second Comment Letter on SCAG's Draft Technical Methodology to Estimate Greenhouse Gas Emission for Connect SoCal (January 2024)
• CARB staff's Comment Letter on the Draft 2024 Regional Transportation Plan/Sustainable Communities Strategy (January 2024)
• CARB staff's Third Comment Letter on SCAG's Draft Technical Methodology to Estimate Greenhouse Gas Emissions for 2024 Connect SoCal (March 2024)

2020 RTP/SCS

• CARB Executive Order accepting the Southern California Association of Governments' (SCAG) determination that the Final SCS would meet the region's GHG emissions reduction targets (October 2020)
• CARB staff's technical evaluation of SCAG's Final Sustainable Communities Strategy (October 2020)
• 2020-2045 Regional Transportation Plan/Sustainable Communities Strategy, adopted September 2020
• CARB staff's Second Comment Letter on the Proposed Final 2020 RTP/SCS (April 2020)
• CARB staff's Comment Letter on the Draft 2020 Regional Transportation Plan/Sustainable Communities Strategy (January 2020)

2016 RTP/SCS

• CARB Executive Order accepting the Southern California Association of Governments' (SCAG) determination that the Final SCS would meet the region's GHG emissions reduction targets (June 2016)
• CARB staff's technical evaluation of SCAG's Final Sustainable Communities Strategy (June 2016)
• 2016-2040 Regional Transportation Plan/Sustainable Communities Strategy, adopted April 2016

Past evaluations are available on request, please email sustainablecommunities@arb.ca.gov

Related CARB Comment Letters

• July 2023 Comment Letter from California Air Resources Board Executive Officer Steven Cliff, Ph.D., to the California Department of Transportation (Caltrans) District 12 on the Draft Environmental Impact Report for the I-5 Red Hill Avenue to OC/LA County Line Managed Lane Project.