published journal article

Health and equity impacts from electrifying drayage trucks

Abstract

Diesel heavy-duty drayage trucks (HDDTs) serving the Ports of Los Angeles and Long Beach in Southern California are large contributors to regional air pollution, but cost remains an obstacle to replacing them with zero-emission HDDTs. To quantify the health and equity impacts of operating diesel HDDTs, we built a microscopic simulation model of a regional freeway network and quantified their emissions of PM2.5 (particulate matter with a diameter < 2.5 μm) and CO2 in 2012 and 2035, before estimating their contribution to selected health outcomes. We found that 483 premature deaths ($5.59 billion) and 15,468 asthma attacks could be attributed to HDDTs in 2012. Regulations and technological advances could shrink these impacts to 106 premature deaths ($1.31 billion) and 2,142 asthma attacks in 2035 (over 2/3 accruing to disadvantaged communities) despite population growth and a 145 % jump in drayage traffic, but they still justify replacing diesel HDDTs with zero-emission HDDTs by 2035.

research report

Considering Fare-Free Transit in The Context of Research on Transit Service and Pricing: A Research Synthesis

Abstract

In this report, the research team examines both the substantial research literature on transit pricing and use and the literature on free and reduced-fare (FAR) programs. In general, we find that free and reduced-fare programs can take many forms, and the idea of “fare-free” transit is far from a one-size-fits-all proposition. Second, while reducing or eliminating fares does indeed increase ridership, all else equal, transit research has consistently found that riders tend to be more service-elastic than fare-elastic. In other words, they tend to respond more to service improvements than price reductions, which means that, at the margin, money “spent” on fare-free programs (in the form of foregone revenues) may attract fewer riders than if that money were put toward improving service. Third, the social equity dimensions of fare-free transit are many, ranging from considering the share of fare-free benefits that flow to higher-income riders to the potential racial equity benefits of reduced fare enforcement policing on transit.

dissertation, thesis, or capstone

Alternative Fuel Adoption Behavior of Heavy-duty Vehicle Fleets

book/book chapter

Understanding and Modeling the Impacts of COVID-19 on Freight Trucking Activity

Abstract

Restrictions on travel and in-person commercial activities in many countries (e.g., the United States, China, European countries, etc.) due to the global outbreak and rapid spread of the coronavirus disease 2019 (COVID-19) have severely impacted the global supply chain and subsequently affected freight transportation and logistics. This chapter summarizes the findings from the analysis of truck axle and weight data from existing highway detector infrastructure to investigate the impacts of COVID-19 on freight trucking activity. Three aspects of COVID-19 truck impacts were explored: drayage, long and short-haul movements, and payload characteristics. This analysis revealed disparate impacts of this pandemic on freight trucking activity because of local and foreign policies, supply chain bottlenecks, and dynamic changes in consumer behavior. Due to the ongoing effects of COVID-19, it is not yet possible to distinguish between transient and long-term impacts on freight trucking activity. Nonetheless, a future expansion of the study area and the incorporation of other complementary data sources may provide further insights into the pandemic’s impacts on freight movement.

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.

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.

policy brief

Barrier Effects of Freeways for Pedestrian and Bicycle Travel

presentation

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