In 2013, then-Governor Jerry Brown signed Senate Bill (SB 743) into law. Pursuant to that direction, the Governor’s Office of Planning and Research (OPR) and the California Natural Resources Agency promulgated regulations and technical guidance that eliminated automobile level of service (LOS) – a measure of automobile delay – as a transportation impact metric for land development projects under the California Environmental Quality Act (CEQA), and replaced it with Vehicle Miles Traveled (VMT) – a measure of the amount of vehicular travel. Actual implementation of the LOS-to-VMT shift was left up to lead agencies—the agencies with primary approval authority over a given project, which for land development projects is usually leading a local government (city or county). Agencies were required to start using a VMT-based metric by July 1, 2020.

Using LOS as the guiding metric for transportation impacts prioritizes vehicular flows and speed. As a result, it has had increasingly well-recognized consequences, including increasing the cost of infill development in urban areas (where roadways are typically more congested at baseline, making project-level transportation impacts more likely) and generally making the built environment more auto-centric. And many planners and policymakers viewed VMT as a more appropriate metric for achieving sustainability goals, like reduced greenhouse gas (GHG) emissions, improved public health and safety, and more streamlined infill development amidst California’s ongoing housing crisis. However, the LOS-to-VMT shift was also expected to create numerous challenges for transportation analysts, given the often-limited resources of local governments, the ingrained nature of LOS in transportation impact analyses, and the perceived lack of established practice with respect to VMT estimation, mitigation, and monitoring.

With those concerns in mind, we undertook this study to investigate how local governments have been implementing the LOS-to-VMT shift for land development projects. We first explored whether and how local governments considered VMT impacts in CEQA analyses prior to the mandated change in transportation impact analysis metrics. We then used document review, direct outreach, and expert interviews to catalogue how each of California’s 539 cities and counties have responded to SB 743, focusing on jurisdictions’ acknowledgment of the policy shift, thresholds of VMT impact significance, VMT impact estimation methods (and tools), VMT impact mitigation guidance (and tools), VMT mitigation monitoring, inter-jurisdictional collaboration, continued use of LOS, and perceived effect of the LOS-to-VMT shift on land use development. The data set stored here summarizes our inventory findings.