Travel Behavior

Independent and Interactive Association of Reported Impairment in Fatal Crashes Among Young California Drivers: A Cross-Sectional Analysis

Lotito, Ainsley
Vaca, Federico E.
Li, Melody S.
Hu, Siwei
Hill, Linda
Julia Griswold
Li, Kaigang
2026

Objective
To examine the independent and combined associations of reported alcohol, drug, and fatigue involvement with crash fatality among young drivers in California.
Methods
Using 2016-2024 injury crash data from the University of California, Berkeley Transportation Injury Mapping System, we performed logistic regression to examine the association between reported driver impairment and crash fatality among drivers aged 15-24. Additive interaction was assessed using binary impairment indicators and interaction terms. Relative excess risk due to interaction (RERI) and 95%...

Hybrid Work and the Restructuring of Urban Mobility in U.S. Cities

Chen, Baoqi Eileen
Marta Gonzalez
2026

Entering the post-pandemic era, cities navigate a new normal shaped by hybrid work and space-time flexibility, but existing evidence is spatially scattered and temporally limited. Here we develop an analytical approach that examines this reorganization through three dimensions: remote work adoption via sector composition, daily travel behavior via trip-level metrics, and functional urban form via mobility-derived measures. To capture the interplay of urban dynamics, we synthesize three complementary spatial metrics. In particular, coupling overall trip centrality with work-trip...

Modeling the Travel Effects of Telework and Hybrid Work: Reshaping Duration, Distance, and Timing of Non-work Travel

Hamad, Nadim
Tahlyan, Divyakant
Said, Maher
Susan Shaheen
Joan Walker
Mahmassani, Hani
Stathopoulos, Amanda
2026

Telework has historically been framed as a means to reduce traffic congestion and alleviate the environmental and energy use impact of transportation. The COVID-19 pandemic precipitated a rapid and widespread shift to remote work, triggering a broad set of interconnected changes in travel behavior that extend well beyond commuting and continue to reshape daily activity patterns. In the contemporary labor market, hybrid work models have gained varied degrees of acceptance by employers and employees, prompting renewed interest in understanding their broader implications for individual...

Lifetime Cost of Battery, Fuel-Cell, and Plug-in Hybrid Electric Vehicles

Mark Delucchi
Tim Lipman
2010
This chapter reviews the estimates of the full social lifetime cost of a battery electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), and a fuel-cell hybrid electric vehicle (FCEV), which consists of the initial and periodic costs of owning and operating a vehicle, including some nonmarket costs that are incurred by the society as a whole. When compared with a conventional gasoline internal combustion engine vehicle (ICEV), advanced BEVs, PHEVs, and FCEVs have higher initial costs, lower fuel costs, lower external costs, possibly higher insurance costs, and possibly lower...

Evaluation of Fuel Cell Auxiliary Power Units for Heavy-Duty Diesel Trucks

Christie-Joy Brodrick
Tim Lipman
Mohammad Farshchi
Nicholas P. Lutsey
Harry A. Dwyer
Daniel Sperling
William Gouse
Bruce Harris
Foy King
2002

A large number of heavy-duty trucks idle a significant amount. Heavy-duty line-haul truck engines idle about 20–40% of the time the engine is running, depending on season and operation. Drivers idle engines to power climate control devices (e.g., heaters and air conditioners) and sleeper compartment accessories (e.g., refrigerators, microwave ovens, and televisions) and to avoid start-up problems in cold weather. Idling increases air pollution and energy use, as well as wear and tear on engines. Efforts to reduce truck idling in the US have been sporadic, in part because it is widely...

Behavioral Response to Hydrogen Fuel Cell Vehicles and Refueling: Results of California Drive Clinics

Elliot Martin
Susan Shaheen
Tim Lipman
Jeffrey Lidicker
2009

Over the last several decades, hydrogen fuel cell vehicles (FCVs) have emerged as a zero tailpipe-emission alternative to the battery electric vehicle (EV). To address questions about consumer reaction to FCVs, this report presents the results of a “ride-and-drive” clinic series (N=182) held in 2007 with a Mercedes-Benz A-Class “F-Cell” hydrogen FCV. The clinic evaluated participant reactions to driving and riding in an FCV, as well as vehicle refueling. Pre-and post-clinic surveys assessed consumer response. More than 80% left with a positive overall impression of hydrogen. The majority...

Trends and 2025 Insights on the Rise of Electric Vehicles in the USA

Matteo Muratori
Doug Arent
Morgan Bazilian
John Bistline
Brennan Borlaug
Austin Brown
Pierpaolo Cazzola
Ercan Dede
Chris Gearhart
David Greene
Alan Jenn
Alissa Kendall
Catherine Ledna
Yanghe Liu
Tim Lipman
Sreekant Narumanchi
Ahmad Pesaran
Ramteen Sioshansi
Thomas Timbario
Kevin Walkowicz
Arthur Yip
2025

Plug-in electric vehicles (EVs) are reshaping the transportation energy landscape, providing a practical alternative to petroleum fuels for a growing number of applications. EV sales grew 55× in the past decade (2014–2024) and 6× since 2020, driven by technological progress enabled by policies to reduce transportation emissions as well as industrial plans motivated by strategic value of EVs for global competitiveness, jobs and geopolitics. In 2024, 22% of passenger cars sold globally were EVs and opportunities for EVs beyond on-road applications are growing, including solutions to...

Electric Vehicle Charge Management Strategies to Benefit the California Electricity Grid

Tim Lipman
Yuhao Yuan
2025

Recent studies suggest that there could be significant value to electric vehicle (EV) drivers and power companies from incorporating EVs into the state’s electrical power grids, known as Vehicle-Grid Integration (VGI). However, the benefits could be highly variable depending on the location of the utility territory, vehicle type and battery capacity, the relevant timeframe, and whether the connection involves only managed charging or includes bidirectional charging permitting vehicle to grid (V2G) power transfer, and other factors. Various studies conducted to date generally conclude that...

Driving California’s Transportation Emissions to Zero

Austin Brown
Daniel Sperling
Bernadette Austin
J. R. DeShazo
Lew Fulton
Tim Lipman
Colin Murphy
Jean Daniel
Gil Tal
Carolyn Abrams
Debapriya Chakraborty
Daniel Coffee
Sina Dabag
Adam Davis
Mark Delucchi
Kelly Fleming
Kate Forest
Juan Carlos Garcia Sanchez
Susan Handy
Michael Hyland
Alan Jenn
Seth Karten
Blake Lane
Michael Mackinnon
Elliot Martin
Marshall Miller
Monica Ramirez-Ibarra
Stephen Ritchie
Sara Schremmer
Joshua Segui
Susan Shaheen
Andre Tok
Aditya Voleti
Julie Witcover
Allison Yang
2021

The purpose of this report is to provide a research-driven analysis of options that can put California on a pathway to achieve carbon-neutral transportation by 2045. The report comprises thirteen sections. Section 1 provides an overview of the major components of transportation systems and how those components interact. Section 2 discusses the impacts the COVID-19 pandemic has had on transportation. Section 3 discusses California’s current transportation-policy landscape. These three sections were previously published as a synthesis report. Section 4 analyzes the different carbon scenarios...

Electric Vehicle Charge Management for Lowering Costs and Environmental Impact

Elpiniki Apostolaki-Iosifidou
Marco Pruckner
Soomin Woo
Tim Lipman
2020

As the number of electric vehicles is increasing, there is a pervasive call for research and new strategies in the field of vehicle grid integration. Using electric vehicle real-time data, drivers' spatial behavior and patterns can be derived for their morning and evening commute. These patterns combined with dynamic electricity costs, wholesale and retail, and variable greenhouse gas (GHG) emissions, lead to significant outcomes on savings and environmental impact. In this study, electric vehicle charging management is analyzed for the case of north California, using real world data. The...