policy brief

Women Have Smaller Activity Spaces Than Men, Especially in Households with Children

Publication Date

September 3, 2025

Author(s)

Fariba Siddiq, Zhiyuan Yao, Evelyn Blumenberg

Abstract

Differences in how men and women travel have long been a focus in transportation research. Many studies have explored how socially-defined gender roles influence travel decisions and behaviors, consistently highlighting disparities between men’s and women’s travel patterns. For example, compared to men, women tend to make more caregiving and household-related trips, have shorter commutes, and are more likely to combine multiple destinations or purposes into a single tour. This body of research often concentrates on standard measures of travel—such as the number of trips taken, how far and for how long people travel, and travelers’ experiences— while also considering the influence of neighborhood design. However, travel patterns also are shaped by broader social structures and inequalities, which are not captured by these traditional measures. To better understand sex differences in travel, this study examined disparities in the size of an individual’s “activity spaces,” defined as the geographic area a person covers during daily activities, such as commuting, shopping, socializing, and leisure. The study draws on detailed trip data from the confidential California add-on to the 2017 National Household Travel Survey (NHTS), which provides the exact starting and ending locations for each trip taken on the survey day. The study estimates the size of each person’s activity space and compare patterns between men and women. It then explore how these differences relate to individual, household, and neighborhood characteristics.

policy brief

Advancing Community-Identified Strategies to Transform Roadways in California’s San Joaquin Valley

Abstract

Disparities in exposure to roadway hazards (e.g., pollution, noise) remain stubbornly persistent due to structural inequalities embedded in the built environment. Research has consistently documented racial/ethnic and socioeconomic disparities in traffic exposures nationwide, including heightened exposure to heavy-duty truck traffic, a significant source of noise and pollution. Such disparities also exist in the provision of sidewalks, bike lanes, and street trees, which can help mitigate roadway dust, noise, and pollution and can increase pedestrian safety, encourage walking and cycling, and provide health benefits.

This publication describes how the research team evaluated opportunities and barriers to using a community steering committee process approach to advance environmental justice and transportation equity. Through interviews and case study analysis, the team examined the role community leaders played in the prioritization and implementation of three community-identified strategies that mitigate roadway hazards in three AB 617 communities in California’s San Joaquin Valley – Stockton, South Central Fresno, and Arvin/Lamont. These strategies include (1) vegetative barriers between roadways and sensitive land uses; (2) expanded sidewalk infrastructure; and (3) revised heavy duty truck route designations.

research report

Between the Forest and the Trees: Community Strategies to Transform Roadways in California’s San Joaquin Valley

Abstract

Expanding participation of historically disenfranchised groups within decision-making processes is an important strategy to increase equity within transportation planning but traditional engagement practices (e.g., public meetings, focus groups) have historically done little to address the needs of disadvantaged communities. This study evaluates the opportunities and barriers to using a community steering committee participation model within transportation planning to advance equity and environmental justice. It utilizes interview and case study analysis to examine the experiences of residents and community leaders in prioritizing community-identified strategies to mitigate roadway hazards in three AB 617 communities in California’s San Joaquin Valley – Stockton, South Central Fresno, and Arvin/Lamont. It investigates the role resident and CBO members played in the prioritization, approval, and implementation of three strategies to transform roadways and mitigate air pollution, noise, dust, and safety hazards: (1) new vegetative barriers between major roadways and sensitive land uses; (2) expanded sidewalk infrastructure; and (3) revised heavy-duty truck route designations. Findings demonstrate that “meaningful involvement” for impacted communities within transportation planning will require officials, residents, and organizations to commit to an ongoing process of experimentation and learning about the most effective approaches for advancing transportation equity and environmental justice.

Impacts of Remote/Hybrid Work and Remote Services on Activity and Transportation Patterns

Status

In Progress

Project Timeline

May 1, 2025 - March 31, 2026

Principal Investigator

Campus(es)

UC Davis

Project Summary

This project will provide science‐based robust information on the behavioral impacts of information and communication technology (ICT) based remote activities on travel choices, including telework, hybrid work, and online shopping. The study will analyze data from the California Mobility Panel, which has been built with rounds of data collection in 2018, 2019, spring and fall 2020, 2021, and 2023, and will be complemented by a new round of data collection in fall 2024. With unique, rich panel data, the project will model complex relationships around remote activities in a single modeling framework, which examines cross‐domain and bidirectional causal effects. The project will employ robust analytical approaches to estimate the effects of remote activities on travel patterns under different land use configurations. The project will greatly improve the understanding of the impacts of remote/hybrid work and other remote services and inform State and planning agencies by shedding light on the complex ways remote activities affect short‐term daily routines (e.g., telecommuting vs. commuting trips, travel mode choice, and spatial/ temporal trip distributions) and long‐term choices (vehicle choice, residential location and real estate development), and will help understand the impacts on vehicle miles traveled (VMT) and transportation‐based greenhouse gas (GHG) emission impacts.

policy brief

What Would it Take for Drivers to Adopt Eco-Driving Behaviors?

Abstract

Climate change in California could greatly impact the state’s economy, nature, and public health. One strategy to reduce fuel consumption and greenhouse gas emissions from the transportation sector is eco-driving. Eco-driving is a set of behaviors or driving styles that encourage fuel-efficient driving that could help minimize energy consumption anywhere from five to 30 percent. With the advance of connected-vehicle technologies, the dynamic eco-driving concept uses real-time vehicle-specific information to optimize vehicle speed and reduce fuel consumption and emissions.

This policy brief finds that driver motivations for adopting eco-driving behaviors varies, perceived ease of use was a key factor influencing a
driver’s intention to use an eco-driving system, and (3) based on the result of the driving simulator experiment, drivers may become distracted while trying to follow the information provided by the eco-driving interface.

Investigating the Evolution of Residential Self-Selection in the Post-COVID Era: The Transition to Digital Lifestyles and Changing Travel Behaviors

Status

In Progress

Project Timeline

May 1, 2025 - June 30, 2026

Principal Investigator

Project Team

Campus(es)

UC Davis

Project Summary

The COVID-19 pandemic has caused a profound transformation in individuals’ residential location choices and travel patterns. Traditional determinants of where to live, such as housing affordability or proximity to work/amenities, now closely intersect with the convenience of remote work and other online activities. This transition reshapes how individuals choose their living environment and organize their travel during the day. To navigate this evolving landscape, this research will delve into the residential self-selection in the post-COVID era. Central to the researchers’ investigation is understanding individuals’ shifting tendencies towards digital nomadism and the impact of this transition on housing preferences and activity-travel behavior. The researchers seek to uncover to what extent factors like the convenience of remote activities, hybrid work schedules, and tech-savviness influence residential and travel choices. Furthermore, the researchers will explore the equity considerations inherent in these decisions, examining how sociodemographics intersect with the evolving structure of residential self-selection. To achieve these objectives, the researchers will employ a targeted sampling methodology to recruit individuals who have relocated over the last 12 months, as well as those who have not moved since the start of the pandemic in March 2020. Through the analysis of this dataset that consists of movers and non-movers, the researchers will have the opportunity to (1) track the factors impacting relocation decisions and those influencing residential stability, (2) explore the effects of the remote activities both on residential and travel choices, and (3) assess the differences in remote activity participation and residential location choice across various population segments. These findings will not only inform planning and policy decisions but also set a baseline for future studies focusing on the interplay between residential self-selection, digital lifestyles, and housing preferences.

research report

Headed Out Less: Analyzing Teen and Young Adult Travel Trends in the 21st Century

Publication Date

August 4, 2025

Author(s)

Andy Fung, Fariba Siddiq, Yu Hong Hwang, Brian D. Taylor

Abstract

Since the turn of the millennium, daily travel per person in the U.S. has been declining. Leading up to the pandemic, travel by older teens and young adults declined even more steeply than among older adults. After collapsing early in the pandemic, per capita travel by all ages has rebounded, but remains below pre-pandemic levels. To explore changes in personal travel, particularly among younger travelers, we examine National Household Travel Survey data from 2001, 2009, 2017, and 2022 to compare measures of everyday travel by youth (aged 15 to 29) with middle-aged adults (aged 30 to 59). The data presented in this report point to even lower levels of youth travel compared to pre-pandemic levels. Trips for all purposes have declined in absolute terms, especially for shopping/errands and, for youth in particular, social/recreational purposes. In relative terms, private vehicle use has increased, and travel by public transit and active modes has decreased. These shifts in personal travel – down overall and toward cars – suggest that pandemic-prompted travel shifts toward fewer out-of-home activities and increased use of information and communications technologies for shopping and other trips may be having enduring effects on personal travel, particularly among younger travelers.

Exploring the Impacts of Working at Home and Online Shopping on Post-Pandemic Travel and Transportation Policy in California

Status

In Progress

Project Timeline

August 5, 2024 - August 31, 2026

Principal Investigator

Project Team

Yage Liu

Campus(es)

UC Berkeley

Project Summary

The COVID-19 pandemic of ongoing changes in the workplace and within households that have significantly influenced travel patterns. Foremost among these are two related trends: people working for pay at home, and increasing household reliance on online shopping and home package delivery. Household travel over this period has markedly changed, with a precipitous falloff in transit ridership and an increase in the share of trips conducted via auto.

This research project explores how working from home and urban freight delivery have shaped household travel behavior in the post-pandemic period. Specifically, the project team will: (i) review empirical literature on trends in working from home and home freight delivery (and the relationship between them) before and during the pandemic; (ii) conduct data description and analysis of four national secondary data sources available through 2022, and explore the relationship between working at home, home freight delivery, online shopping, and patterns in trip frequency and distance by mode; (iii) conduct an online survey in one or more large metropolitan areas in California to explicitly investigate current self-reported and pre-pandemic household behavior, focusing on working at home, online shopping, home freight delivery, and travel behavior as mediated by occupation, income, neighborhood characteristics, and race/ethnicity; and (iv) as a final step, explore policy and planning responses by regional and local agencies.

Steering California’s Transportation Future: A Report on Possible Scenarios and Recommendations

Status

Complete

Project Timeline

January 19, 2022 - July 14, 2022

Principal Investigator

Project Team

Campus(es)

UCLA

Project Summary

What will California’s transportation and land use future look like? Will Californians gain more mobility and housing options that support the state’s economic, social, and climate goals? Or will the car continue to shape what cities look like and how people get around in them? These questions are important because how Californians live and move in the future will be shaped by investments and policies made today. In this project, the researchers investigated the future of transportation, land use, and planning in California by exploring four transportation/land use scenarios for 2050 with a panel of 18 experts. The four scenarios were: (1) more city living and lots of traffic, (2) easy to get around without a car, (3) you’ll need a car to get around, and (4) lots of travel choices, but most will drive. Their consensus opinion was that the most desirable scenario (“Easy to Get Around without a Car”) is also the least likely to materialize, due to faults in the political planning process. Despite promising state policies to increase transportation choices, problematic local land use politics and patterns appear likely to yield a future scenario (“Lots of Travel Choices, but Most Will Drive”) that continues car dependence and chronic congestion, absent a significant rebuilding of government trust and capacity.d

Evaluating Place-Based Transportation Plans

Status

Complete

Project Timeline

September 22, 2022 - September 30, 2023

Principal Investigator

Project Team

Campus(es)

UCLA

Project Summary

California has increasingly turned to place-based, community-driven programs such as Transformative Climate Communities (TCC), the Community Air Protection Program (CAPP), and Regional Climate Collaboratives (RCC) to address the twin priorities of climate change and environmental justice. Transportation improvements are at the heart of these programs because of the potential to mitigate air pollution, greenhouse gas emissions, and inequities in access to transportation. However, these efforts are inherently difficult to evaluate as they often involve a diverse set of projects with different timelines and locations. Moreover, evaluators often face the challenge of isolating the effects of individual programs. Carefully selected control sites can support this effort, but no two communities are exactly alike, limiting the ability of evaluators to make meaningful comparisons. This research addresses how place-based climate action efforts are being evaluated, and what insights from the broader policy and plan evaluation research literature might inform evaluation design. The focus is on place-based, community-driven programs in California that encompass multiple interventions to address intertwined issues of transportation justice, climate change, and air pollution. While TCC, RCC, CAPP, and the Sustainable Transportation Equity Project (STEP) are the most high-profile programs, the project will also consider planning grants such as Sustainable Communities Planning Grants and Community-Based Transportation Plans. For each funded program site the research team will review planning and evaluation documents and annual reports to compile a dataset of data collection and evaluation activities classified by (1) type of activity being assessed (planning vs. implementation), (2) evaluation indicator (e.g. air quality, transportation accessibility), (3) data source (e.g. interviews, air sensors), and program design (e.g. cross-sectional vs. longitudinal, inclusion of control sites). The research team will complement the review of these documents with 10-20 key informant interviews with staff from state and local agencies to help understand how the evaluations are proceeding in practice, and which aspects of place-based program evaluations have proved most valuable, challenging, and scalable to other programs.