Abstract

Ensuring the resilience of urban road networks is essential for public safety and economic stability, especially in cities like Los Angeles that face frequent natural hazards, such as earthquakes, wildfires, and flooding. When making capital investments in such environments, it is equally important to consider fairness in both the decision-making process and its outcomes. In this research study, the research team developed a data-driven framework and implemented it using a web-based software tool to identify priority road segments for investment. To do this, the researchers rated individual roads on several key attributes, including the importance of the road in the network, level of physical deterioration, and hazard risks such as steep slopes or flood-prone areas. The team complemented publicly available data on roads and their attributes with fine-grained “hyperlocal” geospatial information from sensors. Finally, the researchers considered equity by applying socioeconomic indicators of roadway users, which prioritizes roadway segments most likely to benefit vulnerable communities. The research team applied this tool to the Hillsides area of Los Angeles. The result is a comprehensive framework and a powerful tool for guiding infrastructure improvements that are both equitable and resilient.

Abstract

The January 2025 Eaton and Palisades fires destroyed homes and roads across L.A. County. The experience revealed how urgently transportation systems must restore mobility and access after a fire or other major disaster—even though rapid transportation rebuilding can lock in unsafe road designs and miss chances to advance long-term resilience and community priorities.

Abstract

The California Environmental Quality Act (CEQA) requires lead agencies to evaluate the environmental impacts of major projects, including highway expansion projects, and to mitigate those impacts to the extent feasible. In 2013, SB 743 (Steinberg) changed how transportation impacts are evaluated by shifting the performance measure from traffic delay to vehicle miles traveled (VMT), a measure of total driving. This change reflected evidence that the metric of VMT captures the influence that transportation projects have on driving behavior and its related environmental and social impacts, such as greenhouse gas emissions, air pollution, safety, and public health.

How have lead agencies implemented the requirement to analyze and mitigate VMT induced by highway expansion projects? To better understand how SB 743 has affected highway expansion projects in practice, the team reviewed state regulation and guidance and evaluated the Environmental Impact Reports (EIRs) for the six highway expansion projects that have started the environmental review process since the California Department of Transportation (Caltrans) adopted guidance in 2020 to implement SB 743. In this brief, the research team focuses on how lead agencies propose to mitigate any increases in VMT from each of the six highway expansion projects, including the measures proposed, the extent to which mitigation reduces VMT, the cost associated with mitigation, and sources of funding for VMT mitigation.