UC Davis Institute of Transportation Studies

This research presents a risk-informed framework to derive metrics characterizing and tracking the safety performance of heavy-duty automated vehicles (HD-AVs) operations. A combination of traditional and novel hazard identification methods are leveraged to study potential human-system interactions in HD-AVs operations, ranging from safety drivers to remote operators.

A rapid transition to a near-zero-emission transportation system in California and Europe will require rapid uptake of transportation technologies, changes in transportation services, and investments in associated infrastructure. These in turn require policy innovations. This report compares California and EU policies across three broad areas: 1) greenhouse gas (GHG) targets for 2030 to 2050; 2) progress on reducing GHG emissions from different transportation modes; and 3) current strategies and policies to achieve targets. Differences by region and across major modes are identified. Strategies cover electrification, uptake of hydrogen, aviation and shipping fuels, and modal shifts. Policies include regulatory requirements (fuel economy and CO2 standards, fuel standards); incentive programs, including taxation, feebates, and others; direct investment programs; equity considerations and environmental justice-related initiatives. In both geographies, a range of impactful policies are in place. However, these fall short of guaranteeing that targets will be met, and more actions will likely be needed. Some possibilities are presented, with a particular focus on pricing strategies.

Anthropogenic noise and light have been shown to impact wildlife behavior, distribution, movement, and population fitness and survival. Traffic noise and light can inhibit wildlife use of areas adjacent to roads, impair wildlife perception of traffic risks, and cause a barrier effect to wildlife occurrence and movement well beyond road edges. A critical action being taken by states to repair wildlife movement across roadways is construction of wildlife crossings, theoretically providing a safe passage across roads. Planning the location of theses crossings and to some degree their design currently does not take into account traffic noise and light impacts on wildlife approaching the structures. The authors developed statewide models of traffic noise and light intrusion into areas adjacent to state highways to aid understanding of wildlife responses to noise and light and to aid locating and designing crossings to maximize wildlife approach and use. These models have the added benefit of estimating traffic impacts as part of environmental analysis associated with delivering transportation projects. The authors used the NoiseModeling software in QGIS and novel light-modeling tools developed in ArcGIS to model the “noise-scape” and “light-scape” at high-resolution around California state highways. They used different putative sources of traffic noise and light and model propagation (depending on traffic volumes) of both across adjacent landscapes out to at least 1 kilometer. The authors tested the models in the field using transects of noise and light measurements. The outputs were digital (raster) maps that showed the high and low impact areas.

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This study examines the relationship between levels of access to zero-emission vehicles (ZEVs) at car dealerships in California and rates of ZEV adoption in surrounding areas. ZEV accessibility scores for census tracts—based on available ZEV inventory and proximity to dealerships—correlated significantly with ZEV adoption rates, even after controlling for income, demographics, charging infrastructure, and consumer incentives. Our results suggest that a 1% increase in ZEV accessibility correlated with an increase in ZEV adoption by 0.73% in disadvantaged communities (DACs) versus 0.125% in non-DACs. This indicates a latent demand in DACs constrained by supply-side barriers. Dealership-based incentives positively correlated with local ZEV adoption. Policies that support equitable inventory distribution among dealerships, expanded dealership-based incentive programs, and coordination with charging infrastructure planning may increase ZEV adoption in DACs.

Cargo e-bikes are emerging as a promising solution for sustainable urban freight delivery, offering advantages over conventional van-based systems in emissions reduction, congestion mitigation, and operational flexibility. This white paper examines the current state of cargo e-bike deployment in the United States, identifies key barriers to adoption, and provides evidence-based recommendations for policymakers and urban planners. Despite a rapidly growing global market—with projected annual growth of 11–15% through 2034—cargo e-bike deployment faces three interconnected challenges: infrastructure gaps (microhub locations, bicycle network coverage, and parking); regulatory inconsistenciesacross jurisdictions regarding vehicle specifications and permitted infrastructure use; and operational challenges including higher upfront costs and battery-related concerns. To overcome these barriers, this report recommends that cities establish microhub networks, expand bicycle infrastructure, ensure adequate parking with charging capabilities,develop consistent regulatory frameworks, and implement financial incentives and pilot programs. Coordinated action across these domains can enable cargo e-bikes to realize their potential as transformative elements of sustainable urban logistics.

This study investigates free and reduced fare pass programs (FRFPs) for K-12, post-secondary, and college students across California since the COVID-19 pandemic and their role in ridership recovery. A survey of 67 transit agencies, including 34 with established FRFPs, indicates that most of them maintained their FRFPs between fiscal years 2018-2019 and 2022-2023, showcasing agencies' resilience despite financial uncertainty. LA Metro's GoPass enrolled over 241,000 students and generated 1.2 million monthly boardings, inspiring similar initiatives. Post-pandemic, K-12 FRFPs saw significant expansion, improved funding, and a surge in ridership across participating agencies. These findings underscore the positive influence of fare-based incentives on student mobility and attendance.

In 2020, pursuant to Senate Bill (SB) 743 (2013), the California Department of Transportation (Caltrans) adopted guidance requiring that the induced travel effects of capacity expansion projects on the State Highway System be analyzed as a part of the environmental review process under the California Environmental Quality Act. However, despite the fact that induced travel also has economic effects, most conventional benefit-cost analysis tools do not account for induced travel, at least not fully. In this study, the authors examined how induced travel is and can be incorporated into the California Life-Cycle Cost/Benefit Analysis Model (Cal-B/C) maintained by Caltrans. They found that induced travel is not calculated automatically within Cal-B/C. Instead, induced travel must be incorporated manually by the analyst by adjusting the average daily trips on the project information sheet. This can produce wildly divergent benefit/cost ratio outputs depending on whether and how induced travel is incorporated, as demonstrated by the authors’ sensitivity analysis using the benefit-cost analysis prepared for the Yolo 80 Corridor Improvements Project. Indeed, four of the scenarios in the sensitivity analysis resulted in negative benefit/cost ratios, and eight of the scenarios resulted in lower B/C ratios than the baseline result that was actually submitted to the California Transportation Commission. Yet neither Caltrans nor the California Transportation Commission rigorously checks whether Cal-B/C analyses prepared by or submitted to them accurately incorporate induced travel, despite the fact that the benefit/cost ratio projections for proposed highway capacity expansion projects can be instrumental in determining whether those projects get funded. The report concludes with four recommendations for better incorporating induced travel into Cal-B/C analyses. 

Transportation access is a significant issue in low-income, rural, and otherwise underserved communities in the US, with few affordable and reliable alternatives to car ownership. Carsharing is one promising alternative to improve access among these communities. This study examined the implementation and outcomes of an electric vehicle carsharing service launched in Richmond, California by Míocar. The findings are based on surveys with members, an interview with senior Míocar staff, and an analysis of service utilization data provided by Míocar. The Richmond service experienced a variety of implementation problems related to limited space for vehicles and chargers, vandalism of vehicles and hubs, and transitions between funding sources that required the service to re-launch new vehicle hubs and interrupted the continuity of service. However, utilization of the service was strong (700 reservation hours, 4,000 reservation miles) given its availability. Outcomes related to transportation equity and mode shifts, such as the value of carshare in improving mobility and reducing personal vehicle miles traveled were similar to those in Stockton and Tulare and Kern counties.

Autonomous trucks raise complex and interconnected questions about public safety and the future of labor. This white paper examines this safety and workforce connection through a review of multidisciplinary literature and findings from expert interviews to evaluate three automated trucking pathways: driverless trucks, truck platooning, and automated driving assistance systems (ADAS). A central finding is that human autonomy teams will remain integral across all three trajectories. Humans will co-design, test, supervise, and maintain these systems, playing enduring roles in pre-drive, front-line (including in-vehicle), and remote (off-vehicle) settings. These roles represent durable labor categories whose scope, skill requirements, and job quality will be shaped by regulatory design choices that also influence public safety outcomes. This paper finds that partial automation is likely to expand more rapidly than fully driverless operations, creating near-term opportunities to leverage ADAS technologies to improve safety and workforce retention. Investments in retraining and education can help workers transition into emerging roles, while advances in ADAS and ADS safety standards should explicitly address risks to both workers and the public. Greater coordination across government, labor, and industry will also be essential to implement these strategies and ensure that autonomous trucking supports higher-quality jobs and leads to safer, more resilient goods movement systems.

This report considers motivations, obstacles, and policies and programs adopted at the state, regional, and local levels in California to support transit-oriented development (TOD). Regulatory policies adopted by the state in recent years to induce TOD are discussed, as well as state-led and regionally-managed funding programs. Findings are presented from two on-line surveys of local planning directors, and 51 interviews with regional and local planners. The findings point to multiple obstacles to achieving TOD, including market factors, resident opposition, and lack of sufficient funding for implementation, such as for necessary infrastructure to support new development. The most commonly adopted local policies to support TOD include streamlining of environmental review requirements, mixed-use zoning and upzoning (permitting higher densities), improving bike and pedestrian facilities, development of Specific Plans for neighborhoods, and mechanisms to ease accessory dwelling units (ADUs). The survey findings indicate that policies and programs initiated from multiple levels of government are deemed effective for inducing TOD. A recent one-off TOD-supportive funding program that was managed regionally, called the Regional Earley Action Program (REAP), is found to be rated as very valuable both by regional and local planners, leading to the recommendation that this program be instated on an ongoing basis with dedicated funding. The report also concludes that policies deemed effective for inducing TOD, especially funding affordable housing and addressing the nexus of zoning, CEQA streamlining for infill, permit streamlining through ministerial review, and support for Specific Plans, should continue to receive policy support from the state legislature and regional agencies.