We consider how cities are responding to California’s legislation that preempts them from requiring parking close to transit. To what extent are cities sticking to the letter of the law? Which cities are going further and taking the opportunity to go beyond the scope of the state requirements? Or are some cities attempting to evade the spirit of the law?
published journal article 
policy brief
California High-Speed Rail (HSR) is a publicly funded high-speed rail system currently under construction in the state. According to the California High-Speed Rail Authority (CHSRA), service on the initial 119-mile segment from Madera to Bakersfield is projected to begin in 2029. The full Phase 1 will later connect Anaheim and Los Angeles with San Francisco via the Central Valley in 2033. The ride between Los Angeles and San Francisco will cover a total distance of 380 miles and take 2 hours and 40 minutes.
Caltrans’ 2021 Interregional Transportation Strategic Plan, makes HSR the state’s highest transportation priority for the San Francisco Bay Area — Los Angeles corridor. Quantifying its public benefits are difficult but include reducing traffic demands on California’s roads and airports.
published journal article
Emerging evidence suggests that the recovery of transit ridership post-COVID has been uneven, especially for rail transit. This study aims to understand the station area land use, built form, and transit network characteristics that explain station-level changes in transit ridership pre- and post-COVID, and explores the degree to which those changes are rail transit-specific or the result of overall changes in visits to station areas. Specifically, the study examines ridership changes between 2019 and 2021 for 242 rail stations belonging to the Bay Area Rapid Transit (BART), San Diego Metropolitan Transit System (MTS), Sacramento Regional Transit (SACRT), and LA Metro and associate those changes with the built environment, socio-demographics, and rail network characteristics around each station using regression analysis. The study also compares these changes in ridership to overall changes in activity aggregated by station area type. The study found there was an overall decrease in station-level ridership of 72 %, but changes were not uniform, with 92 stations decreasing more and 152 stations decreasing less. The study also found that ridership declined more drastically than overall station area activity across all four rail systems, which implies that rail transit riders were more sensitive to pandemic-related changes than other commuters. The findings suggest that a rail transit ridership recovery strategy should strategize to reinvent and reinforce downtowns as destinations, and shift rail transit services to appeal to non-commute travel, as well as enhance bike and pedestrian accessibility around stations.
research report
This study provides a method to quantify the benefits of reducing the costs from flight delays by shifting air passenger traffic to high-speed rail (HSR). The first estimate was the number of flight reductions by each quarter hour for airport origin and destination pairs based on HSR ridership forecasts in the California High-Speed Rail 2020 Business Plan. Lasso models are then applied to estimate the impact of the reduced queuing delay at SFO, LAX and SAN airports on arrival delays at national Core 29 airports. Finally, these delay reductions are monetized using aircraft operating costs per hour and the value of passenger time per hour. The research team applied several different variations of this approach, for example, considering delay at all 29 Core airports or just major California airports, different scenarios for future airport capacity and flight schedules, and different forecasts for future HSR ridership. The estimated mid-range delay cost savings are $51-88 million (2018 dollars) in 2029 and $235-392 million (2018 dollars) in 2033. The estimated savings are similar to, but slightly lower than, those based on cost estimates to upgrade airport capacity to handle passenger traffic that could be diverted to HSR.
published journal article
Now that dockless electric bike-share systems have become a fixture in major cities in the U.S., it is important to understand why someone chooses to use the service. Beyond socio-demographics, factors such as mode-related attitudes, the social environment, and the availability of the service may influence both its adoption and frequency of use. This study modeled dockless electric bike-share adoption and use frequency using data collected from a household survey and a bike-share user survey from the Sacramento region. The study used integrated choice and latent variable models to understand the influence of attitudes on electric bike-share adoption and use frequency. Three latent variables − bike affinity, car necessity, and bike social environment − were developed using responses to eleven statements. The models show that apart from socio-demographics, attitudes related to bike affinity and bike social environments significantly and positively influence bike-share adoption with a large effect size, whereas the car necessity attitude significantly and negatively influences the use frequency with a large effect size. Individuals with low incomes are less likely to adopt the bike-share service. The availability of electric bike-share in key locations (home and/or work and/or school) where an individual frequently goes significantly and positively influences adoption with a large effect size but does not influence use frequency. Findings from this study can inform the dockless electric bike-share policies of cities as well as the rebalancing strategies of service providers.
published journal article published journal article policy brief
Under California Assembly Bill 617 (Garcia, 2017), local and state agencies are working to reduce air pollution exposure in low income communities. These communities—often referred to as AB 617 communities—are disproportionately impacted by air pollution due to their proximity to transportation corridors, industrial installations, and logistics centers. A research team at the University of California, Davis investigated the impact of truck parking related activities on air quality in California’s AB 617 communities in Kern County, including truck idling, time spent searching for parking, and parking locations in communities. Searching for parking involves trucks driving extra miles to find available parking spaces, which leads to additional fuel consumption and increased emissions of pollutants such as nitrogen oxides (NOx) and particulate matter (PM 2.5 and PM 10). Once parked, prolonged or illegal parking can exacerbate congestion, noise, and localized pollution. These combined activities heighten exposure to harmful emissions in EJ communities, potentially leading to health issues (e.g., asthma and cardiovascular diseases). A comprehensive policy framework addressing truck parking facilities, management, and air pollution control is crucial for improving air quality and living conditions in AB 617 communities. There are a number of initiatives that could contribute to improving the conditions on these communities.
Remote work, online shopping, and streaming surged during the pandemic and remain high today, changing how people and goods move. This project synthesizes research on post-pandemic travel patterns and interviews transportation leaders and equity advocates to explore how policies and investments should evolve to meet new demands while supporting environmental and equity goals.
research report California’s housing affordability and transit ridership crises are heavily influenced by how cities zone for new development. Cities often face a choice between targeted corridor-based upzoning, which allows more housing along main roads, and more expansive area-based upzoning, which opens surrounding neighborhoods to growth. This project compares how these approaches affect housing supply, affordability, and transit ridership in several California metro areas. Using detailed zoning and land use data, it will estimate where new housing is most likely to be built and its potential to support equitable transit access, housing affordability, and walkable communities.
