Area of Expertise: Travel Behavior, Land Use, & the Built Environment

Do Existing Policies Still Hold? Quantifying Enduring Post-COVID Travel Patterns and Calibrating Policies

Status

In Progress

Project Timeline

January 1, 2026 - December 31, 2026

Principal Investigator

Siddhartha Gulhare

Project Team

Yongsung Lee, David Bunch

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

Campus(es)

UC Davis

Project Summary

The pandemic has caused lasting changes in when, where, and why people travel, affecting transportation policies built on pre-pandemic habits. This proposal explores the scale and structure of travel shifts after the pandemic. It evaluates whether California’s Sustainable Communities Strategies (SCS), targeted programs like Green Means Go, remain effective, and if SB 743 aligns with new travel behaviors. Utilizing LEHD LODES and Replica data, the project team analyzes origin-destination patterns by time-of-day, trip purpose, and residential choices across industries from 2019 to 2024.

The research uses term clusters (representing complete communities), where residents can live, work, and access daily needs within the same area. First, the team analyzes intra- and inter-cluster travel changes to determine whether travel has become localized or dispersed. Second, researchers examine whether the self-sufficient cluster model, where people can live, work, and recreate within the same area, is consistent across industries and income groups. Finally, the team evaluates if hybrid work patterns have changed job-housing balance and impacted the resilience of clusters targeted for infill and VMT reduction.

This study offers timely empirical insights to assist state policymakers (SACOG, SCAG) in revisiting policy assumptions, updating SB 375 implementation strategies, and identifying where local plans may need recalibration to meet California’s goals.

published journal article

The Evolving Travel and Driving Behaviors of Older U.S. Travelers in the 21st Century

Publication Date

December 4, 2025

Associated Project(s)

Working from Home and Travel: What Does the Future Hold?

Author(s)

Phoebe Chiu, Yu Hong Hwang, Fariba Siddiq, Brian D. Taylor

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment
View published journal article

Abstract

The number and share of U.S. residents aged 60+ years have increased substantially since 2000, and both are projected to expand further in the years ahead. The mobility patterns of this growing cohort of travelers are consequential and only lightly studied since the COVID-19 pandemic. To better understand the travel patterns of older adults and how they have evolved since the turn of the century broadly, and following the COVID-19 pandemic in particular, this article analyzes national data from the 2001, 2009, 2017, and 2022 iterations of the U.S. National Household Travel Survey. The article compares travelers in their 60s, 70s, and above with middle-aged (aged 30–59 years) and younger travelers (aged 5–14 and 15–29 years) across multiple dimensions. The study finds that trip-making and person-miles of travel have been falling for older and younger travelers for years and declined dramatically following the pandemic. Meanwhile, both trip lengths and driving rates have grown. The study finds, as well, that older adults are driving later in life over time, and non-driving adults are making fewer trips and traveling fewer miles than those who remain behind the wheel. The study also finds that the odds of giving up driving because of a medical condition or disability have declined significantly since 2009, controlling for an array of factors associated with travel. The practical and policy implications of reduced trip-making, longer trips, higher rates of driving, and declining driver cessation among older travelers are many, and warrant more attention from transportation analysts and policymakers in the years ahead.

Related Publications

research report

What are the best ways to organize, coordinate, and deliver public transit service in large metropolitan areas? A Research Synthesis

March 3, 2026

policy brief

Organizing and Delivering Public Transit Service in California

February 26, 2026

research report

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

August 4, 2025

policy brief

Which Pandemic-Induced Changes in Work and Commuting Are Sticking, and What Does this Mean for Public Policy?

April 1, 2025

published journal article

Going Nowhere Faster: Did the Covid-19 Pandemic Accelerate the Trend Toward Staying Home?

October 30, 2024

policy brief

Older Adults are Driving Later in Life, but Getting Out Less

March 1, 2025

policy brief

Young Adults Aren’t Leaving Home, Socializing, or Traveling as Much Post-Pandemic

March 1, 2025

policy brief

Americans are Spending More Time at Home and Traveling Less Post-Pandemic

March 1, 2025

op-ed

America is becoming a nation of homebodies

March 10, 2025

other

Press Release: Not Going Out is the “New Normal” Post-Covid, Say Experts

research report

Transformative Community Planning as a Tool for Advancing Mobility Justice: Two Case Studies Using Community-Based Participatory Action Research and Racial Equity Impact Assessment

Publication Date

November 1, 2025

Associated Project(s)

Transformative Community Planning as a Tool for Advancing Mobility Justice

Author(s)

Charisma Acey, Margaretta Lin, Daniel Lindheim, Rowland Awadagin Herbert-Faulkner

Areas of Expertise

Safety, Public Health, & Mobility Justice Travel Behavior, Land Use, & the Built Environment
View research report

Abstract

Top-down transportation planning practices have historically ignored the needs and concerns of low-income communities of color, which can lead to residential and commercial displacement as public investments increase land values and rents. The concept of mobility justice centers the needs of communities that have historically been excluded from transportation planning decisions. We partnered with community groups to examine two transportation planning projects in the Bay Area using collaborative research methods. The first was a retrospective analysis of the East Bay Bus Rapid Transit project in East Oakland that reflects the harms of top-down planning. The second study examined the City of Richmond’s Transformative Climate Communities projects, a more collaborative approach to planning with low-income communities involved at every stage. The top-down planning model employed in the East Oakland case study resulted in significant health, safety, and displacement impacts that could have been avoided. The Richmond case study shows project changes occurring as a direct result of using mobility justice principles.

Related Publications

policy brief

Transformative Community Planning Can Advance Mobility Justice

November 1, 2025

policy brief

Transformative Community Planning Can Advance Mobility Justice

Publication Date

November 1, 2025

Associated Project(s)

Transformative Community Planning as a Tool for Advancing Mobility Justice

Author(s)

Charisma Acey, Margaretta Lin

Areas of Expertise

Safety, Public Health, & Mobility Justice Travel Behavior, Land Use, & the Built Environment
View policy brief

Abstract

Top-down transportation planning practices have historically ignored the needs and concerns of low-income communities of color. Federal funding guidelines, agency objectives, regional and local planning processes, and community priorities often conflict with each other at the expense of the health, safety, and livelihood of vulnerable populations. Decades of discriminatory government policies and disinvestment have enabled gentrification, particularly in underserved neighborhoods where new transportation investments make these areas more accessible and attractive to wealthier, often white, residents, which can lead to residential and commercial displacement as public investments increase land values and rents. Mobility justice, which treats mobility as a fundamental human right and promotes a version of transportation planning that incorporates distributive, procedural, and recognition justice, offers an alternative framework.

Related Publications

research report

Transformative Community Planning as a Tool for Advancing Mobility Justice: Two Case Studies Using Community-Based Participatory Action Research and Racial Equity Impact Assessment

November 1, 2025

published journal article

State Preemption in Theory and Practice: The Case of Parking Requirements

Publication Date

October 17, 2025

Associated Project(s)

State Preemption and Parking Requirements

Author(s)

Amy Lee, Adam Millard-Ball, Michael Manville

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment
View published journal article

Abstract

In U.S. law, states can override actions of local governments that contravene state interests. In practice, preemptions are often more ambiguous nudges, and local responses can vary by interpretation and interests. This paper explores one such case of state preemption: California’s 2022 law that limited local governments’ ability to require automobile parking. We find that the law’s complexity and ambiguity created intense debates about interpretations, in all jurisdictions, leading to heterogeneous implementation across cities. Local interests also motivated strategic responses to the law, which we present in a threefold taxonomy: cities interested in parking reform used it as a springboard; cities interested in parking reform but facing local resistance used it as a protective shield; recalcitrant cities treated it as an obstacle or subverted the law. Our analysis shows that preemption is not as clear cut as it seems, and what conditions help and hinder changes in actual outcomes.

Related Publications

policy brief

How California cities respond to state-level parking reform

January 22, 2026

published journal article

Hybrid Workers’ Activity Intensity: Post-Pandemic Comparison of Telework-Only and in-Person Workdays

Publication Date

August 29, 2025

Associated Project(s)

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

Author(s)

Patrick Loa, Yongsung Lee, Giovanni Circella

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment
View published journal article

Abstract

The COVID-19 pandemic profoundly reshaped work patterns, with a sizable portion of workers becoming engaged in hybrid work (i.e., combining teleworking and in-person work). This study investigates whether hybrid workers, in the post-pandemic era, participate in out-of-home activities differently on their telework days than on their in-person workdays. Using data from 1,438 hybrid workers in California, US, collected during fall 2023, we estimate a multivariate ordered-response probit model with threshold shifters. Differences in participation across six out-of-home activities (shopping, errands, drop-off/pick-up, eating out, visiting friends and family, and exercise) between telework and in-person workdays are jointly modeled. Workers show greater overall activity participation on telework days, with considerable heterogeneity among individuals. On telework days, women and older workers tend to have lower participation in out-of-home activities. Flexible work schedules are associated with higher participation in social activities. Greater time savings (from not having to physically commute) lead to higher overall participation. The results underscore the importance of policies that support flexible work arrangements, considering their potential to positively affect lifestyle and productivity. Additionally, teleworking at non-home locations is linked to higher activity participation overall, suggesting potential trip-chaining or unique activity allocation strategies that warrant further investigation. The study contributes to the literature on post-pandemic teleworking and activity participation, and offers valuable insights into urban planning, transportation policy, and remote-work policies.

policy brief

Shifting Air Travel to High-Speed Rail Could Save $300 Million in Reduced Airport Delays

Publication Date

June 1, 2022

Associated Project(s)

Assessing Benefits from Shifting Passenger Travel from Air to High-Speed Rail in California

Author(s)

Kaijing Ding, Mark Hansen

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment
View policy brief

Abstract

California High-Speed Rail (HSR) is a publicly funded high-speed rail system currently under construction in the state. According to the California High-Speed Rail Authority (CHSRA), service on the initial 119-mile segment from Madera to Bakersfield is projected to begin in 2029. The full Phase 1 will later connect Anaheim and Los Angeles with San Francisco via the Central Valley in 2033. The ride between Los Angeles and San Francisco will cover a total distance of 380 miles and take 2 hours and 40 minutes.

Caltrans’ 2021 Interregional Transportation Strategic Plan, makes HSR the state’s highest transportation priority for the San Francisco Bay Area — Los Angeles corridor. Quantifying its public benefits are difficult but include reducing traffic demands on California’s roads and airports.

Related Publications

research report

Quantifying Major Travel Delay Reduction Benefits from Shifting Air Passenger Traffic to Rail

June 1, 2022

published journal article

Rail transit ridership changes in COVID-19: Lessons for station area planning in California

Publication Date

September 23, 2025

Associated Project(s)

Rail Transit Ridership in California: Lessons Learned from Station Area Assessments

Author(s)

Meiqing Li, Daniel Rodriguez, Susan Pike, Michael McNally

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment
View published journal article

Abstract

Emerging evidence suggests that the recovery of transit ridership post-COVID has been uneven, especially for rail transit. This study aims to understand the station area land use, built form, and transit network characteristics that explain station-level changes in transit ridership pre- and post-COVID, and explores the degree to which those changes are rail transit-specific or the result of overall changes in visits to station areas. Specifically, the study examines ridership changes between 2019 and 2021 for 242 rail stations belonging to the Bay Area Rapid Transit (BART), San Diego Metropolitan Transit System (MTS), Sacramento Regional Transit (SACRT), and LA Metro and associate those changes with the built environment, socio-demographics, and rail network characteristics around each station using regression analysis. The study also compares these changes in ridership to overall changes in activity aggregated by station area type. The study found there was an overall decrease in station-level ridership of 72 %, but changes were not uniform, with 92 stations decreasing more and 152 stations decreasing less. The study also found that ridership declined more drastically than overall station area activity across all four rail systems, which implies that rail transit riders were more sensitive to pandemic-related changes than other commuters. The findings suggest that a rail transit ridership recovery strategy should strategize to reinvent and reinforce downtowns as destinations, and shift rail transit services to appeal to non-commute travel, as well as enhance bike and pedestrian accessibility around stations.

Related Publications

policy brief

Decline of Rail Transit Requires New Strategies

September 1, 2024

research report

Rail Transit Ridership Changes in COVID-19: Lessons from Station Area Characteristics

September 1, 2024

research report

Quantifying Major Travel Delay Reduction Benefits from Shifting Air Passenger Traffic to Rail

Publication Date

June 1, 2022

Associated Project(s)

Assessing Benefits from Shifting Passenger Travel from Air to High-Speed Rail in California

Author(s)

Kaijing Ding, Mark Hansen

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment
View research report

Abstract

This study provides a method to quantify the benefits of reducing the costs from flight delays by shifting air passenger traffic to high-speed rail (HSR). The first estimate was the number of flight reductions by each quarter hour for airport origin and destination pairs based on HSR ridership forecasts in the California High-Speed Rail 2020 Business Plan. Lasso models are then applied to estimate the impact of the reduced queuing delay at SFO, LAX and SAN airports on arrival delays at national Core 29 airports. Finally, these delay reductions are monetized using aircraft operating costs per hour and the value of passenger time per hour. The research team applied several different variations of this approach, for example, considering delay at all 29 Core airports or just major California airports, different scenarios for future airport capacity and flight schedules, and different forecasts for future HSR ridership. The estimated mid-range delay cost savings are $51-88 million (2018 dollars) in 2029 and $235-392 million (2018 dollars) in 2033. The estimated savings are similar to, but slightly lower than, those based on cost estimates to upgrade airport capacity to handle passenger traffic that could be diverted to HSR.

Related Publications

policy brief

Shifting Air Travel to High-Speed Rail Could Save $300 Million in Reduced Airport Delays

June 1, 2022

published journal article

What factors influence the adoption and use of dockless electric bike-share? A case study from the Sacramento region

Publication Date

September 1, 2025

Associated Project(s)

Investigating the Influence of Dockless Electric Bike-share on Travel Behavior, Attitudes, Health, and Equity, How Dock-less Electric Bike Share Influences Travel Behavior, Attitudes, Health, and Equity: Phase II

Author(s)

Hossain Mohiuddin, David Bunch, Tatsuya Fukushige, Dillon Fitch-Polse, Susan Handy

Areas of Expertise

Public Transit, Shared Mobility, & Active Transportation Travel Behavior, Land Use, & the Built Environment
View published journal article

Abstract

Now that dockless electric bike-share systems have become a fixture in major cities in the U.S., it is important to understand why someone chooses to use the service. Beyond socio-demographics, factors such as mode-related attitudes, the social environment, and the availability of the service may influence both its adoption and frequency of use. This study modeled dockless electric bike-share adoption and use frequency using data collected from a household survey and a bike-share user survey from the Sacramento region. The study used integrated choice and latent variable models to understand the influence of attitudes on electric bike-share adoption and use frequency. Three latent variables − bike affinity, car necessity, and bike social environment − were developed using responses to eleven statements. The models show that apart from socio-demographics, attitudes related to bike affinity and bike social environments significantly and positively influence bike-share adoption with a large effect size, whereas the car necessity attitude significantly and negatively influences the use frequency with a large effect size. Individuals with low incomes are less likely to adopt the bike-share service. The availability of electric bike-share in key locations (home and/or work and/or school) where an individual frequently goes significantly and positively influences adoption with a large effect size but does not influence use frequency. Findings from this study can inform the dockless electric bike-share policies of cities as well as the rebalancing strategies of service providers.

Related Publications

published journal article

Examining the Effects of the Sacramento Dockless E-Bike Share on Bicycling and Driving

January 3, 2021

published journal article

Does Bike-share Enhance Transport Equity? Evidence from the Sacramento, California Region

May 6, 2023

policy brief

Electric Bike-share in the Sacramento Region is Replacing Car Trips and Supporting More Favorable Attitudes Towards Bicycling

June 1, 2020

research report

Investigating the Influence of Dockless Electric Bike-share on Travel Behavior, Attitudes, Health, and Equity

March 1, 2020

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