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Open Access Publications from the University of California
Cover page of Further Implications of Freeway Siting in California: Freeway Development and Communities of Color in Colton, Fresno, and San Diego

Further Implications of Freeway Siting in California: Freeway Development and Communities of Color in Colton, Fresno, and San Diego

(2025)

This study examines the consequences of freeway construction on neighborhoods of color across California, with a focus on socioeconomic changes, route selection, community reactions and resistance, and the disruptions to residents, businesses, and other assets. Expanding on three prior case studies conducted by the research team, this study incorporates three additional case studies: South Colton, West Fresno, and City Heights in San Diego. The construction of freeways was a contributing mechanism to the perpetuation of racial inequality, weakening social institutions, disrupting local economies, and physically dividing neighborhoods. However, the outcomes varied across locations. In South Colton, a freeway was ultimately not built through its community of color, though largely for reasons of construction costs. City Heights, initially a predominantly non-Hispanic white neighborhood, underwent a demographic transformation driven by white flight during a decades-long pause in freeway construction. West Fresno did face consequences from freeway development but was also unique in its diversity of residents pre-freeway, including people of color and non-Hispanic white immigrant communities. Freeway development contributed to transforming West Fresno into an overwhelming community of color. Across these cases, freeways fragmented communities, displaced residents, and reinforced pre-existing racial divides. These racialized impacts stemmed from systemic socioeconomic marginalization and exclusion of people of color in the planning process. Today, public investments aimed at reconnecting communities offer an opportunity to address the enduring harms caused by freeways. However, achieving meaningful progress will require the integration of restorative justice principles into the planning and decision-making processes.

Cover page of Road Capacity as a Fundamental Determinant of Vehicle Travel

Road Capacity as a Fundamental Determinant of Vehicle Travel

(2025)

Reducing vehicle miles traveled (VMT) is a central plank of climate policy in California. VMT, however, has proved stubbornly resistant to policies to reduce it. While urban growth has become more compact and public transit service levels have been maintained or increased, these positive trends have not translated into less driving. This report argues that substantial reductions in vehicle travel in congested urban regions can only be achieved through reducing road capacity. It may be difficult to achieve substantial reductions in vehicle travel by relying solely on public transit, walking and cycling, and land use planning for compact, mixed-use development without an equal emphasis on limiting road capacity expansions, and even reducing current capacity.

Cover page of Capturing Transit Rider Perspectives on Safety and Harassment: Lessons from San Francisco

Capturing Transit Rider Perspectives on Safety and Harassment: Lessons from San Francisco

(2025)

Personal safety concerns continue to be one of the most critical issues among transit riders and women and gender minorities in particular. These safety concerns stem from the experience of sexual harassment that people who identify as women face frequently. While harassment can be a common occurrence, the vast majority of these experiences go unreported to transit agencies, leaving agencies without information about the magnitude of this problem on their system. This report details work with the San Francisco Municipal Transportation Agency (SFMTA) in their efforts to understand and address this problem. The SFMTA, working with two UCLA graduate students, designed a survey that drew from previous survey efforts and was tailored to address their interests and needs. This report documents the process of developing and deploying the questionnaire, in an effort to help other agencies take the first steps to better understanding rider safety and harassment. Through breaking down SFMTA’s approach, this report intends to inspire andinform similar efforts at other agencies.

Cover page of Evaluating the Seismic Vulnerability and Resilience of BART’s Berkeley Hills Tunnel

Evaluating the Seismic Vulnerability and Resilience of BART’s Berkeley Hills Tunnel

(2025)

Critical nodes in transportation networks, such as major transit tunnels and interchange stations, are vital for maintaining system functionality following a disruptive event such as a large earthquake. This project focuses on evaluating the seismic resilience of BART’s Berkeley Hills Tunnel that intersects the Hayward Fault, one of California's most active seismic zones. The Hayward Fault poses a significant risk, with the potential for a magnitude 7+ earthquake that could severely impact the tunnel, potentially disrupting BART service and affecting the broader transit network. This study employs the latest fault displacement hazard data and models to estimate the probability of fault rupture displacements and assesses the resulting damage. It then evaluates the likelihood of service interruptions caused by potential Hayward Fault events. Theresults suggest that the tunnels may experience minor to significant damage depending on the amplitude of the faultdisplacement, which can lead to repair times ranging from a few weeks to over a year. The findings highlight the importance of improving tunnel resilience to minimize service disruptions and ensure efficient recovery following major earthquakes.

Cover page of Moving Beyond the Colors: The Full Life-Cycle Emissions of Hydrogen Production Pathways for California

Moving Beyond the Colors: The Full Life-Cycle Emissions of Hydrogen Production Pathways for California

(2024)

There is growing interest in the use of hydrogen as a transportation fuel but the environmental benefits of using hydrogen depend critically on how it is produced and distributed. Leading alternatives to using fossil natural gas to make hydrogen through the conventional method of steam methane reforming include using electrolyzers to split water into hydrogen and oxygen, and the use of biogas as an alternative feedstock to fossil natural gas. This report examines the latest carbon intensity (CI) estimates for these and various other hydrogen production processes, adding important nuances to the general “colors of hydrogen” scheme that has been used in recent years. CI values for hydrogen production can vary widely both within and across hydrogen production pathways. The lowest CI pathways use biomass or biogas as a feedstock, and solar or wind power. The report also analyses jobs creation from new hydrogen production facilities and shows that these benefits can be significant for large-scale facilities based on either future biomass/biogas-to-hydrogen or solar-hydrogen production technologies. Recommendations include setting stricter goals for the state’s Low Carbon Fuel Standard (LCFS) program to continue to reduce the carbon footprint of California’s transportation fuels.

Cover page of Parking, Working from Home, and Travel Behavior

Parking, Working from Home, and Travel Behavior

(2024)

Drawing on the California Household Travel Survey, we demonstrate strong associations between choosing to drive and having free parking at work or home. We find that the median household vehicle in California spends 22 hours a day parked, and that households with parking included in the rent or purchase price of their homes are more likely to drive,and less likely to use transit. We further find that employees with free parking at work are more likely to drive for their commutes. We estimate regressions that analyze the decision to work from home. Largely for data reasons, these regressions are less conclusive.

Cover page of Fuel-Cell Vehicle and Hydrogen Transitions in California: Scenarios, Cost Analysis, and Workforce Implications

Fuel-Cell Vehicle and Hydrogen Transitions in California: Scenarios, Cost Analysis, and Workforce Implications

(2024)

To achieve California’s ambitious climate goals, a shift to hydrogen fuel for some transportation sectors may be essential.In this report, we explore the build-out of a hydrogen fuel distribution system including uptake of light-, medium-, and heavy-duty fuel cell electric vehicles. Our analysis of Base and High Case scenarios includes costs of building and operating a hydrogen vehicle and fuel system and estimates workforce impacts. We consider scenarios with about 125,000 vehicles by 2030 in the Base Case and 250,000 in the high case. This increases by an order of magnitude to 2045. Vehicle and station investment costs associated with the Base Case reach anywhere from $4 to 12 billion USD by 2030 and increase by a factor of eight by 2045. Costs per kg of hydrogen, including fuel transmission to stations and station costs delivered to vehicles, could be in the range of $4 to 8 per kg. This becomes $6 to 10/kg as a final delivered cost, if production of hydrogen were to cost $2/kg. Workforce impacts in the Base Case include 600 to 2,200 jobs created by 2030, rising rapidly thereafter. This report was prepared by the ITS-UC Davis Energy Futures Hydrogen Program in partnership with the UCLA Luskin Center for Innovation.

Cover page of Risk Assessment for Remotely Operation of Level 4 Automated Driving Systems in Mobility as a Service Transport

Risk Assessment for Remotely Operation of Level 4 Automated Driving Systems in Mobility as a Service Transport

(2024)

The recent technological advances in Automated Driving Systems (ADS) have fueled interest in the use and impact of vehicle fleetsinvolved in driverless passenger transport services. This research identifies key safety risks associated Level 4 ADS-equipped vehicleoperation for fleets employed for Mobility as a Service (MaaS) applications. The study goes beyond assessing the functional safety ofthe ADS-equipped vehicles to explore the role of fleet operators in ensuring the operational safety of the vehicle fleets through remote driving assistance functions. This work identifies key responsibilities of the fleet operators in implementing risk reductionmeasures related to organizational management of change, training remote supervisors, ensuring suitable working conditions, enforcing vehicle connectivity and dispatching requirements, and coordinating incident mitigation procedures, training, tools, and work conditions. The study employs a hazard identification methodology that combines traditional and innovative methods to analyze risks involving human, software, and hardware systems. The study identified twenty hazard scenarios arising from system failures, human errors, and unsafe interactions during different operational phases. These are ranked based on their impact on safety and resource intensity, enabling fleet operators to make better decisions regarding resource allocation. By implementing these actions, fleet operators can prevent and mitigate safety hazards in the operation of ADS-equipped fleets though remote monitoring and driving assistance functions. The hazards and risk mitigation activities identified in this report may also improve the operational safety of passenger vehicles equipped with ADS technology as they become more widely deployed in future large-scale commercialoperations.

Cover page of Evaluating Place-Based Transportation Plans

Evaluating Place-Based Transportation Plans

(2024)

We ask how place-based transportation plans are being evaluated, and what insights from the broader policy and plan evaluation research literature might inform evaluation design. We complement a review of the evaluation literature with six expert interviews with 15 people. We find that California agencies and their community partners have high expectations for evaluations of place-based transportation plans. So far, however, those evaluations have been less successful in providing detailed information on outcomes and the causal impact of interventions. This does not reflect the shortcomings of the evaluation teams, but rather the inherent challenges in holistically assessing a diverse set of projects on different implementation timelines in a project area with porous boundaries. There is also a fundamental difficulty with the evaluation scale. California’s place-based transportation plans have often been evaluated individually. But in general, evaluations, particularly quantitative causal inference methods, are most effective with a larger number of projects or sites. We suggest a two-pronged approach to addressing the tensions that we identify between place-specific knowledge and generalizable conclusions. The first prong, at the site level, would emphasize process evaluations and assessment of outputs and outcomes. The second prong would focus on impacts across multiple sites and the extent to which place-based transportation programs have a causal role.