With the adoption of Senate Bill (SB) 743, the State of California changed the method of traffic analysis required through the California Environmental Quality Act (CEQA) for publicly- and privately-initiated projects. The law changed the way local jurisdictions, like the County of San Diego (County), analyze transportation impacts from development projects and identify mitigation measures to reduce those impacts. SB 743 became effective on July 1, 2020.

The San Diego Board of Supervisors adopted the Transportation Study Guide (TSG) which established VMT thresholds and screening criteria on Sept 28, 2022. The TSG can be found here:

https://www.sandiegocounty.gov/content/sdc/pds/SB743.html

The previous practice of evaluating traffic transportation impacts used on-road congestion or level of service (LOS). SB 743 requires the amount of driving and length of trips – as measured by "vehicle miles traveled" or VMT – be used to assess transportation impacts on the environment for CEQA review. These impacts will be reduced or “mitigated” by options such as increasing transit, providing for active transportation such as walking and biking, and participating in mitigation banks.