Driving California’s Transportation Emissions to Zero

Identifying pathways to reach carbon neutrality in California’s transportation sector


California has a history of leading on climate policy and has increased its ambition in recent years. Greenhouse gas emissions from transportation account for more than half of all emissions in the state (including emissions from oil production and refining), but have been challenging for the state to address. The Budget Act of 2019 (AB 74) funded two studies, administered by the California Environmental Protection Agency, to: 1) identify strategies to reduce emissions from transportation energy use, and 2) identify strategies to manage the decline in fossil fuel production and associated emissions in parallel with reductions in demand. The first study was conducted by the University of California Institute of Transportation Studies at four campuses, UC Davis, UC Berkeley, UC Irvine, and UCLA. The second study was conducted by UC Santa Barbara.


To meet California’s goals, transportation will need to undergo transformational change. Current and future policies must consider the impacts and outcomes of their implementation and prioritize equity, health, and workforce impacts of the transition to zero-carbon transportation. Changes to reduce vehicle miles traveled (VMT), to increase the adoption of electric vehicles, to adopt the use of alternative fuels, and to increase the efficiency of the freight will undoubtedly result in lower greenhouse gas emissions. These policies should consider the impacts on economic opportunities for the communities that work in the fossil fuel industries and also tend to be the most negatively impacted by emissions. Because of that, this study also focuses on job creation and integrated skill delivery as a means to increase economic opportunity.


The University of California Institute of Transportation Studies was selected to lead the study focusing on strategies to transition California’s transportation system to a carbon-neutral basis by 2045, including transitioning to zero emission vehicles, accelerating the use of alternative fuel sources, and reducing vehicle miles traveled. As an intermediate step, the UC ITS published a synthesis of existing research in October 2020 that provides background, policy context, and a “business as usual” scenario. The final report released in April 2021 identifies scenarios, assumptions, and related strategies, tools, options, tradeoffs and benefits for areas where action can be taken now, as well as where additional actions, targets, policies, research and technology development are needed in the medium and longer term. The policy options outlined in the study, when combined, could lead to a zero-carbon transportation system by 2045, while also improving equity, health, and the economy.


The University of California demand study was conducted by researchers from the UC Institute of Transportation Studies, a network with branches at UC Davis, UC Berkeley, UC Irvine, and UCLA. The UC Davis Policy Institute for Energy, Environment, and the Economy coordinated the report’s policy management, and the UC Davis Center for Regional Change led the study’s equity and environmental justice research.