research report

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

Publication Date

January 1, 2025

Author(s)

Esra Zengin, Yousef Bozorgnia, Jonathan P. Stewart

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation

Abstract

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.

policy brief

A Detailed Look at How the Pandemic Changed Travel Patterns Across Regions in Northern California Megaregion

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Many studies have focused on the shifts in travel patterns caused by the COVID-19 pandemic and how travel demand continues to evolve in the post-pandemic era. Key metrics such as trip volume–the total number of trips within a specific area–help explain the pandemic’s impact on travel demand over time. However, to fully understand changes in travel behaviors, it is also important to analyze where trips start and end—otherwise known as Origin-Destination (OD) demand.
To better understand OD demand during and after the pandemic, the research team developed a data-driven methodology to analyze travel patterns across different regions, times of day, days of the week (weekday and weekend), and trip purpose. This study used passively collected location-based data from the StreetLight Data platform (StreetLight Data, 2022) in the form of weekly OD matrices of all vehicle modes, segmented by various relevant variables. It focused on the Northern California Megaregion, which includes 21 counties from the San Francisco Bay Area to the Sacramento region and the northern part of the San Joaquin Central Valley. The study period spanned from January 2019 to October 2021.

policy brief

The Costs and Gains of Raising Truck Speed Limits

Publication Date

October 1, 2024

Author(s)

Michael Zhang, Sarder Rafee Musabbir

Areas of Expertise

Safety, Public Health, & Mobility Justice

Abstract

Highway speed limits are increasing across the United States (Figure 1). There is also a national trend toward uniform speed limits, within states, for both passenger vehicles and trucks. California is one of only seven remaining states that sets different speed limits, with lower speed limits for trucks than passenger vehicles. While higher speed limits provide operational benefits by shortening travel times and fostering economic benefits—especially for the trucking and logistics industries—they can also increase the likelihood and severity of crashes since higher vehicle speeds require longer stopping distances and generate more energy during a collision.
While there is no consensus on the optimal speed limit, research generally shows that lower speed limits reduce the frequency and severity of crashes. Likewise, there is mixed evidence on whether universal (i.e., same for trucks and passenger vehicles) or differential speed limits are safer. While some evidence suggests that setting lower speed limits for heavier trucks that take longer to stop has safety benefits, others argue that differential speed limits create bottlenecks may cause more crashes as cars attempt to overtake slower-moving trucks.
The research team used traffic simulation and statistical models to estimate the costs of crashes, travel time, and vehicle operation for various speed limit scenarios in California. Analysis focused on the economic and comprehensive costs associated with fatal and severe traffic crashes, as outlined by the National Safety Council. They derived key metrics such as traffic speeds, travel times, and distances by simulating typical highway operating conditions. These insights helped calculate the overall economic and operational impact across the state’s highway system.

policy brief

What are the Public Health and Environmental Implications of Drayage Truck Electrification Targets in California?

Publication Date

January 1, 2025

Author(s)

Monica Ramirez-Ibarra, Jean-Daniel Saphores

Areas of Expertise

Freight, Logistics, & Supply Chain Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

To better understand the implications of transitioning drayage trucks to zero-emission, this project analyzed the health impacts and GHG freeway emissions from diesel-powered drayage trucks and the benefits of replacing them with zero-emission trucks, accounting for current and expected air quality regulations. The study area stretched between the San Pedro Bay and the Inland Empire, home to large warehouse complexes. It focused on two years: 2012 (when pre-2007 drayage trucks were phased out in the Clean Air Action Plan), and 2035 (the deadline in Executive Order N-79-20). The analyses incorporated projections of the size and composition of the vehicle fleets from data collected by the California Air Resources Board (CARB), estimates of future emission factors from the U.S. Environmental Protection Agency that account for projected technology improvements, and projected increases in cargo demand at the ports in 2035 compared to 2012.

preprint journal article

A Choice Experiment Survey of Drayage Fleet Operator Preferences for Zero-Emission Trucks

Areas of Expertise

Freight, Logistics, & Supply Chain Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

Many U.S. states are supporting the transition of the heavy-duty vehicle (HDV) sector to zero-emission vehicles (ZEVs), with California leading the way through its policy and regulatory initiatives. Within various HDV fleet segments, California’s drayage fleets face stringent targets, requiring all vehicles newly registered in the Truck Regulation Upload, Compliance, and Reporting System to be ZEVs starting January 2024, and all drayage trucks in operation to be zero-emission by 2035. Understanding fleet operator behavior and perspectives is crucial for achieving these goals; however, it remains a critical knowledge gap. This study investigates the preferences and influencing factors for ZEVs among drayage fleet operators in California. A stated preference choice experiment survey was conducted, developed based on previous qualitative studies and literature reviews. With participation from 71 fleets of various sizes and alternative fuel adoption status, there were 648 choice observations in a dual response design collected, consisting of a forced choice between ZEVs and a free choice between ZEVs and status quo alternatives. Multinomial logit model analyses revealed driving range and purchase costs as significant factors for ZEV adoption, with charging facility construction costs also critical in hypothetical choices between ZEVs and status quo alternatives. Fleet or organization size also influenced ZEV choices, with large fleets more sensitive to operating costs and small organizations more sensitive to off-site stations. These findings enhance understanding in this area and provide valuable insights for policymakers dedicated to facilitating the transition of the HDV sector to zero-emission.

preprint journal article

Small and Large Fleet Perceptions on Zero-emission Trucks and Policies

Areas of Expertise

Freight, Logistics, & Supply Chain Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

Given that small fleets (defined as those with 20 or fewer vehicles) represent a considerable portion of the heavy-duty vehicle (HDV) sector, understanding their perspectives, along with those of large fleets, on zero-emission vehicles (ZEVs) and related policies is crucial for achieving the U.S. HDV sector’s ZEV transition goals. However, research focusing on small fleets or comparing both segments has been limited. Focusing on California’s drayage sector with stringent ZEV transition targets, this study investigates the awareness and perceptions of small and large fleet operators on ZEV technologies and policies established to promote ZEV adoption. Using a fleet survey, we obtained 71 responses from both small and large fleets. We employed a comprehensive exploratory approach, utilizing descriptive analysis, hypothesis testing, and thematic analysis. Findings reveal that both segments generally rated their ZEV knowledge as close to neutral, with about a third reporting limited awareness of the ZEV policy. Both segments highlighted various adoption barriers, including challenges with infrastructure, costs, and operational compatibility. Business strategies under the ZEV policy differed significantly: small fleets planned to delay or avoid ZEV procurement, with some considering relocation, while large fleets were more proactive, with many already having procured or preparing to procure ZEVs. Both segments voiced concerns about the disproportionate impact on small fleets. The findings enhance our understanding of equity issues in ZEV adoption across fleet segments and offer valuable insights for policymakers committed to a more equitable distribution of the impacts. ​​

preprint journal article

Charging Infrastructure Decisions by Heavy-duty Vehicle Fleet Operators: An Exploratory Analysis

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

Insufficient charging/fueling infrastructure poses a major challenge to achieving U.S. policy goals for transitioning the heavy-duty vehicle (HDV) sector to zero-emission vehicles. Addressing the infrastructure needs of HDV fleet operators, who are key demand-side stakeholders, is crucial for developing effective solutions and strategies. This study investigates these needs through a fleet survey of California’s drayage sector, focusing on battery electric trucks. Key aspects examined include preferences for charging locations, access types, charging duration, time-of-day for charging, and innovative solutions like Truck-as-a-Service. Analyzing responses from 53 companies with varying fleet sizes, annual revenues, and operational characteristics, the study employed a comprehensive exploratory approach, utilizing descriptive analysis, thematic analysis, and hypothesis testing. Findings reveal that while most fleets preferred on-site charging, about a quarter, primarily smaller fleets with five or fewer trucks, preferred both on-site and off-site options. Private access was often favored for on-site facilities, though some respondents recognized the benefits of shared access for expanding operational coverage. The study also identified a need for faster charging solutions at both off-site and on-site locations, particularly for long-haul or mixed operations. Time-of-day preferences varied widely, driven by the need for efficient operations. Furthermore, a small proportion of participating fleets preferred Truck-as-a-Service over traditional procurement, predominantly among smaller fleets or those with lower revenues. The comprehensive research findings contribute to a deeper understanding of charging infrastructure needs and offer practical insights for policy practitioners and industry stakeholders committed to advancing zero-emission infrastructure. ​​

policy brief

How Did Transit Service Adjustments During the Pandemic Impact Job Accessibility in the San Francisco Bay Area?

Publication Date

January 1, 2025

Author(s)

Phoebe Ho, Johanna Zmud, Joan Walker

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

This study examined geographic and temporal patterns in service adjustments and evaluated their job accessibility impacts for three major San Francisco Bay Area transit agencies between 2020 and 2023: the Alameda-Contra Costa Transit District (AC Transit), the San Francisco Bay Area Rapid Transit District (BART), and the San Francisco Municipal Transportation Agency (MUNI). This retrospective analysis can help transit agencies develop equitable service strategies in the event of future disruptions.

published journal article

Demand-side challenges and research needs on the road to 100% zero-emissions vehicle

Publication Date

January 1, 2025

Author(s)

Scott Hardman, Amrita Chakraborty, Kelly Hoogland, Claire Sugihara

Areas of Expertise

Zero-Emission Vehicles & Low-Carbon Fuels

Abstract

Most net-zero emissions targets require electrification of the entire light-duty vehicle fleet, and before that the electrification of all new vehicle sales. This paper reviews literature on demand-side issues related to achieving 100% zero-emissions vehicle sales, focusing on plug-in electric vehicles (PEVs). It discusses potential demand-side challenges to increasing PEV sales and related research gaps, including consumer factors (perceptions, knowledge, and consumer characterises), demand-focused policy (incentives), infrastructure, and energy prices. While global PEV sales have substantially increased in recent years, several challenges remain: some demographic groups are currently underrepresented among PEV buyers (e.g. renters, lower income buyers), some car drivers are resistant to PEVs, incentives are influential but have predominantly benefited higher-income new-car buyers and are being phased out, infrastructure is not sufficiently developed or equally distributed, infrastructure is not user friendly, and some households lack charging access. Some issues identified may be related to the early stage of the PEV market, though they will need to be addressed to reach higher PEV sales and PEV fleet shares. Finally, it outlines areas where more research is needed to understand and guide the PEV transition.

policy brief

Assessing the Shift to Remote and Hybrid Work in California throughout the COVID-19 Pandemic

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Abstract

Beginning in 2020, many in-person activities were replaced by virtual activities as a response to the COVID-19 pandemic. This affected fundamental elements of transportation systems such as trip frequency, commute distance, origins, and destinations. For example, remote work and study were widely adopted among workers and students. Still, the ways that the pandemic affected individuals’ work arrangements across different phases of the pandemic and the extent to which full remote work and hybrid work induced by the pandemic might persist in the future are unclear. In addition, recent studies are not conclusive regarding the ways changes in work arrangements do/will impact travel patterns and trip making.