policy brief

Connected and Automated Vehicle Impacts in Southern California: Travel Behavior, Demand, and Transportation System Perspectives

Abstract

Connected and automated vehicle (CAV) technologies received extensive attention in the recent decade. CAVs are vehicles that can drive without a human driver (automated vehicle, or AV) and can communicate with other vehicles and infrastructures (connected vehicle, or CV). The technologies can benefit transportation systems in many aspects, including safety, economics, efficiency and convenience, and accessibility. While studies of CAV operations are accelerated by tons of data collected from on-road tests worldwide, the comprehensive impacts of CAVs on transportation systems are still unclear. These benefits might affect travel behavior fundamentally, which might induce more travel demand, while on the other hand, vehicle automation and connection would enhance roadway capacity. Ultimately, it’s essential to evaluate the CAV impacts on transportation systems in the context of significantly changing travel demand and supply. This study aims to answer the following questions: 1) how the deployment of CAVs impacts people’s travel behaviors in Southern California; 2) to what extent the changes in people’s travel behavior can affect the travel demand; 3) how well can the increased roadway capacity help alleviate the strain on the network with CAV deployment; and 4) will the CAV technologies contribute to the travel accessibility of underserved groups?

policy brief

Student Transportation Options Provided by California Community Colleges Often Limited to Parking Permits and Transit Passes

published journal article

Grocery shopping in California and COVID-19: Transportation, environmental justice, and policy implications

Abstract

To understand how COVID-19 changed grocery shopping and explore implications for transportation and environmental justice, we surveyed in May 2021 California members of KnowledgePanel®, the largest and oldest U.S. probability-based panel. We asked how frequently Californians grocery shopped before and during the pandemic, and how they may grocery shop afterward in-store, online with home delivery (“e-grocery”), or online with store/curbside pick-up (“click-and-pick”). We found that most Californians continued to grocery shop in-person during the pandemic, although less frequently than before. Many relied more on e-grocery (+8.9 %) and click-and-pick (+13.3 %), although older generations remained attached to in-store shopping. African American households grocery shopped in-store less than Whites pre-pandemic; post-pandemic, they may compensate with more e-grocery and click-and-pick. While higher levels of environmental injustice (based on CalEnviroScreen) were associated with less in-store shopping, we found no association with e-grocery or click-and-pick. Our results have implications for travel, food logistics, and parking management.

policy brief

Barrier Effects of Freeways for Pedestrian and Bicycle Travel

research report

Understanding Transportation Programs and Services at California Community Colleges

Abstract

High transportation costs and access barriers can make it difficult for community college students to manage employment, household responsibilities, and education, negatively affecting their academic success. Understanding the state of existing transportation services and programs at California community colleges is the first step to addressing these barriers. We inventoried the transportation services, programs, and costs at 115 of the 116 California community colleges as advertised on each campus’ website. We found that most community colleges offer some form of parking or public transit student subsidies but little else. Due to the state education code, parking costs were similar across campuses. In contrast, transit pass costs varied from $0 to more than $100 per semester. On average, students paid more for transit passes than for parking permits. Throughout the search process, information on the campus’ transportation programs and services was difficult to locate since each campus posted this information in different places on their websites. The findings suggest that more colleges should consider offering low-cost transit passes by assessing a transportation fee or enacting partnerships with other government entities. California community colleges may also want to consider expanding how they provide transportation support and better publicizing information on transportation and standardizing how information is provided. Overall, community colleges, with the support of the State, have opportunities to better support students’ transportation needs to ensure that transportation access is not a barrier to educational outcomes.

presentation

Kent Distinguished Lecture, University of Illinois Transportation Center, Nov 2022: "Data, modeling and emerging technologies on the road to sustainable freight transportation."

policy brief

Rural Electric Vehicle Carsharing is Improving Household Mobility and Reducing Reliance on Personal Vehicles

Abstract

Households in marginalized areas of rural California contend with difficult transportation challenges resulting from infrequent transit service, limited access to app-based rideshare services, and higher vehicle ownership costs associated with long travel distances. In 2014, researchers at the University of California, Davis partnered with the San Joaquin Valley Metropolitan Planning Organization to engage with stakeholders to understand the challenges facing rural residents and develop solutions for improving mobility while reducing greenhouse gas emissions. One outcome of this work was the creation of an electric vehicle (EV) carsharing service known as Míocar. Míocar launched in 2019 and now has 27 vehicles located in eight affordable housing complexes in Tulare and Kern counties. Míocar provides a transportation option that helps to improve the mobility of individuals and households in marginalized communities and reduce greenhouse gas emissions by decreasing reliance on conventional personal vehicles.

research report

Dividing Highways: Barrier Effects and Environmental Justice in California

Abstract

We examine the barrier effects of freeways in California. We analyze the association between freeways and three measures of nearby street connectivity: the composite Street Network Disconnectedness index (SNDi), circuity, and the distance between crossings – underpasses or bridges that enable people to cross the freeway. We also assess the quality of a sample of these crossings for pedestrians and cyclists. We find that barrier effects are most pronounced in communities of color. We also find that even where crossings exist, they are unpleasant or even hazardous for pedestrians and cyclists because of high-speed traffic on on- and off-ramps, and because large volumes of traffic are funneled through a small number of crossings rather than being distributed over a wider network.

published journal article

Cross-sectoral and multiscalar exposure assessment to advance climate adaptation policy: The case of future coastal flooding of California’s airports

Abstract

Climate adaptation is inevitable in managing the climate risk of infrastructure systems and has become an emerging topic in the past decade. Despite the growing need for collaborative and multi-agency efforts in climate change adaptation, however, current airport and transportation governance structures reinforce siloed approaches to manage climate risk. Here we combine a novel coastal flooding exposure assessment of California’s airports and a policy review to address the importance of collaborative climate adaptation by viewing airport infrastructures as interconnected systems across spatial scales and sectors. Our exposure assessment innovates by investigating the airport perimeter, its interconnected infrastructure (road access, ground-based navigation, and communications systems), and multimodal interregional transportation corridors. At the local scale, we find that substantial airport assets are exposed as early as 2020–2040, suggesting the urgency for near-term adaptation actions. Regarding the interconnected infrastructures, 23 unaccounted airports are identified at risk of disruption when compared with existing studies, including global hubs such as the Los Angeles International Airport. At the regional scale, we investigate how exposed airports transfer risk within the interregional multimodal transportation corridors, and we identify the critical airports within these corridors to be prioritized for adaptation. Finally, based on a policy review of more than 100 state legislature and planning documents, the implications of our results are discussed at the national and state levels. This study presents a new generation of infrastructure exposure assessment to climate-induced hazards, by addressing cross-sectoral and multiscalar dependencies that are currently overlooked by adaptation policies. We also argue that new modes of collaborative efforts are needed to achieve effective climate adaptation for interconnected infrastructures.

policy brief

Sustainable Transportation and Just Affordable Housing

Publication Date

October 13, 2022

Author(s)

Allie Padgett, Anne Yoon, Chhandara Pech, Jacob Wasserman, Paul Ong, Tiffany Green

Abstract

California’s intense affordable housing crisis has highlighted the fundamental linkage between land use, transportation, climate policy, and equity. Reducing greenhouse gas emissions, the main contributor to climate change, is a priority policy goal for the state of California, and cutting vehicle miles traveled (VMT) is a key mechanism for achieving this goal. In order to equitably achieve this reduction, it is critical that affordable housing options be situated in areas that facilitate less driving, through reliable access to public transit, walkability, and proximity to employment. These elements, among others, can combine to create more sustainable communities.In the face of rising housing prices, publicly subsidized affordable housing is crucial for low-income and other vulnerable Californians. This study analyzed geographic transportation, environmental, and racial and economic equity indicators alongside the spatial distributions of two affordable housing programs in 2012 and their change from 2012 to 2019:
• Housing Choice Vouchers (HCV), also known as “Section 8”: the nation’s major tenant-based rental support program, a portable voucher designed to cover the gap between 30% of a household’s income and the cost of rent in a market unit.
• Low-income Housing Tax Credit (LIHTC): the nation’s largest project-based affordable housing development program, a tax credit used to subsidize income-restricted, lower-rent housing units.