Transportation Impacts

The California Natural Resources Agency has adopted new CEQA Guidelines that will leave behind level of service in favor of vehicle miles traveled.

Following years of development and public comment, the Office of Planning and Research (OPR) and the Natural Resources Agency have issued new CEQA Guidelines for analyzing transportation impacts.  These new regulations represent a significant shift in analyzing transportation impacts under CEQA.  By July 1, 2020, all CEQA lead agencies must analyze a project’s transportation impacts using vehicle miles traveled (VMT).  VMT measures the per capita number of car trips generated by a project and distances cars will travel to and from a project, rather than congestion levels at intersections (level of service or “LOS,” graded on a scale of A – F).  California’s largest cities have already adopted VMT standards and abandoned LOS, but many other jurisdictions will continue to require LOS analysis — not for CEQA purposes, but because their general plans or other policies require LOS analysis.

In this update, we highlight key aspects of the VMT guidelines and how projects could be impacted by this important change in conducting transportation impacts analysis.


In 2013, the California legislature enacted SB 743, which required, among other things, that OPR adopt new guidelines for assessing transportation impacts and that when enacted, traffic congestion would no longer be considered in assessing a significant impact under CEQA.  The purpose was to better align transportation impacts analysis under CEQA with the state’s goals of reducing greenhouse gas emissions and traffic-related air pollution and promoting multimodal transportation networks and a diversity of land uses.  Under the existing framework of congestion-based analysis using LOS, infill and transit-oriented development is often discouraged because such projects are in areas of existing traffic congestion.  As policymakers and legislators have recognized, congestion-based analysis does not necessarily improve the time spent commuting and is often at odds with state goals of reducing vehicle usage and promoting public transit.  Indeed, a frequent solution to reducing level of service at intersections is to increase roadway capacity, which studies have found can actually lead to an increase in system-wide congestion and an increase in travel time.  It is also now better understood that LOS does not accurately reflect vehicle travel as it only focuses on individual local intersections and roadway segments and not on the entire vehicle trip.

VMT is not a new tool for assessing environmental impacts under CEQA.  It is used to assess a project’s impact on greenhouse gas emissions, air quality, and energy.  Using VMT for analyzing transportation impacts will emphasize reducing the number of trips and distances vehicles are used to travel to, from, or within a development project.  Projects located near transit and/or within infill areas generally have lower VMT than projects in rural or undeveloped areas.  The shift to VMT analysis under CEQA is intended to encourage the development of jobs, housing, and commercial uses in closer proximity to each other and to transit.
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