published journal article

Investigating Travel Demand Heterogeneity During and After the Pandemic in the Northern California Megaregion: A Data-Driven Analysis of Origin-Destination Structural Patterns

Abstract

The study delves into the complexities of travel disruption and recovery during and after the COVID-19 pandemic. Using a data-driven methodology, we explore spatial-temporal patterns across regions by times of the day, weekdays/weekends, and trip purposes. Using passively collected location-based data from January 2019 to October 2021 in the Northern California Megaregion, our analysis compares travel patterns through the structural similarity of origin-destination (OD) matrices. Introducing the concept of a “local sliding geographical window” based on natural trip flow, the study identifies various impacts of the pandemic on travel demand including but not limited to (a) trip volume and recovery (e.g., weekday trips dropped by 47% in April 2020, gradually recovering already by October 2021); (b) impact on home-based work and other trips which were significantly disrupted on weekdays compared with non-home-based; (c) OD pattern changes (e.g., all sub-regions experienced significant changes, but the San Francisco Bay area faced the maximum disruptions); (d) gradual recovery with regional variations (e.g., San Francisco lagged in its travel activity recovery but this improved after April 2021, whereas the Northern San Joaquin Valley recovered fastest); (e) disruption and recovery linked to socioeconomic factors (e.g., parts of San Francisco, characterized by higher income, white-collar jobs, faced maximum disruption, whereas the Northern San Joaquin Valley, with a higher proportion of blue-collar workers, experienced the least disruption); and (f) differential recovery rates across and within regions, with areas rich in white-collar jobs showing slower recovery for work trips compared with areas with a higher proportion of blue-collar jobs.

published journal article

Teleworkers and Physical Commuters During the COVID-19 Pandemic: the Change in Mobility Related Attitudes and the Intention to Telecommute in the Future

Abstract

The COVID-19 pandemic has disrupted commuting habits, with many individuals shifting to telecommuting. This study examines the impact of disrupted commuting habits on psychological constructs, such as attitudes or active lifestyle. Using longitudinal survey data from the California panel study of emerging transportation, the study compares two groups (those who started telecommuting, N = 458, and those who continued physically commuting, N = 523) at two points (early pandemic 2020 and later pandemic 2021). Exploratory factor analysis was used to extract the latent psychological constructs and structural equation modeling was used to model the intention to telecommute in the future for each year. Results show that some psychological constructs (such as attitude toward sustainable modes) remain stable across groups and time, while others (such as concern about pathogens) depend on both group and stage of the pandemic. The intention to telecommute in the future remains high and is mainly dependent on individuals’ attitude toward it and their tech-savviness, rather than on a concern about pathogens or demographics. The findings may inform policies that promote sustainable and flexible mobility options, like telecommuting, that have the potential to enhance work-life balance in a post-pandemic world.

Investigating Opportunities to Mobilize Community Associations to Promote Sustainable Transportation and Land Use

Status

Complete

Project Timeline

September 25, 2023 - January 31, 2025

Principal Investigator

Project Team

Campus(es)

UC Irvine

Project Summary

In recent decades, common-interest housing developments have become prevalent in many American cities. According to the Community Associations Institute’s 2021 estimates, nearly 30% of the U.S. population now lives in a development or area governed by a community association, with homeowners associations being the most common type. Despite the widespread presence of homeowners associations (HOAs), there has been limited research on how they impact the adoption of new mobility technologies, innovative urban neighborhood designs, and sustainable land use and transportation initiatives. HOAs and similar community governing bodies have the authority to impose additional restrictions on community activities, which has often led to them being perceived as obstacles to achieving a more environmentally friendly and inclusive future. While this perception is grounded in reality, it doesn’t fully account for the significant variation in how HOAs operate. This perspective also hinders innovative thinking about how HOAs could contribute to creating more sustainable communities. Exploring ways to engage these influential entities in pursuing various planning objectives is crucial.

This project will improve the collective understanding of how HOAs and other community associations impact sustainable land use and transportation. The researchers will achieve this by: i) creating an integrated geospatial database that includes information about HOAs, land uses (including Accessory Dwelling Units, or ADUs), and transportation indicators, ii) investigating the relationship between the presence or absence of HOAs and factors such as ADU construction, travel patterns, and the built environment, and iii) identifying best practices and extracting lessons from successful cases.

published journal article

A Case for Race and Space in Auto Ownership Modeling: A Los Angeles County Study

Abstract

Auto ownership behavior is driven by complex relationships that can vary dramatically across different traveler groups and communities. Differences in auto ownership among racial groups have been of particular interest, given ongoing efforts to advance equity in transportation outcomes. There are a number of studies documenting racial disparities in auto ownership associated with racial and ethnic residential clustering, termed “automobile mismatch.” Yet, these differences in auto ownership behavior by race and residential location are virtually never considered in models of travel behavior, despite calls for the consideration for race in transportation planning and decision making. This study aims to bridge the gap between understandings of the connections between race and space and transportation outcomes, using Los Angeles County as a case study. A series of auto ownership model specifications are used to investigate statistical connections between the racial and ethnic categories of residents, and neighborhoods, revealing systematic variations across racial and spatial dimensions. The composite model, which includes racial and spatial indicators, outperforms the base model, suggesting that the inclusion of race and space explains significantly more information on variations in auto ownership and provides a superior fit to the data. Our findings also suggest that the exclusion of racial and spatial indicators may lead to overestimation of certain effects, and may completely misrepresent the importance of certain household, individual-level, and built environment effects in explaining auto ownership preferences. Given the increasing attention to equity and representation in transportation outcomes, models that exclude considerations for race and space may be poorly positioned to support meaningful transportation equity analyses.

published journal article

Can Governments Streamline Environmental Impact Analysis to Promote Transit Oriented Development? Evidence from California

Publication Date

March 1, 2025

Author(s)

Bailey Affolter, Jamey Volker, Nicholas Marantz, Susan Pike, Graham DeLeon

Abstract

California’s seminal Sustainable Communities and Climate Protection Act of 2008—Senate Bill (SB) 375—includes two provisions specifically intended to help streamline transit-oriented development (TOD) projects through environmental review (California SB 375, 2008). One provision exempts qualifying TODs from environmental review entirely. The other provision streamlines environmental review for qualifying projects. This study explores the use and effect of those provisions. It first quantifies how much and where the provisions have been used. It then uses interviews and email communications with planning and development practitioners to explore why streamlining is used, whether streamlining actually helps reduce the time, cost, and uncertainty of permitting TOD projects, and how streamlining could be improved to better facilitate TOD projects. The study finds that SB 375 streamlining is a mixed bag. Neither streamlining provision has been used extensively. The full exemption appears to have been avoided because its costs and complications outweigh any streamlining benefit, though the more limited streamlining provision was regarded as having at least some utility. It also found that SB 375-streamlined projects might not be fulfilling SB 375’s more fundament goals—reducing vehicle kilometers traveled and greenhouse gas emissions. The clearest lesson for policymakers is to reduce the eligibility requirements for environmental review streamlining provisions.

policy brief

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

Publication Date

April 1, 2025

Author(s)

Fariba Siddiq, Brian D. Taylor

Abstract

Before the COVID-19 pandemic, most workers were tied to fixed locations and schedules, often necessitating long, stressful commutes that researchers have linked to reduced productivity, and lower overall well-being. During the pandemic, the need for social distancing, together with ongoing advances in communication technologies, led many firms and employees to embrace remote and hybrid work arrangements. Now, in the post-pandemic era, many employees prefer these arrangement and are resisting employers’ “return-to-office” mandates. What is the state of working from home and commuting post-pandemic? This study examined this question using data from the 2022 National Household Travel Survey.

published journal article

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

Abstract

Covid-19 significantly altered work, out-of-home activity participation, and travel, with much activity time being moved into the home. If these patterns hold, they could imply significant long-term changes for homes, businesses, cities, and transportation. We examined data for 34,000 respondents to the American Time Use Survey from 2019 (the pre-pandemic period), 2021 (the pandemic period), and 2022 and 2023 (the post-pandemic period). We used ordinary least squares (OLS) regressions to study participation in 12 out-of-home activities, travel (by auto, transit, and walking), and 16 in-home activities. We observed sharp declines in overall out-of-home activity, travel by all modes, and 10 of the 12 specific out-of-home activities in 2021 compared with 2019, whereas time spent on 13 of the 16 in-home activities rose during that period. By 2023, most of these changes persisted: Time spent out-of-home, traveling by all modes, and on six out-of-home activities remained notably lower in 2023 than in 2019, whereas time spent on nine in-home activities remained higher. The trend away from out-of-home activities and travel appears to be persisting.

policy brief

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

Publication Date

March 1, 2025

Author(s)

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

Abstract

Like much of the developed world, the U.S. is aging. Between 1920 and 2020, the number of people 65 and older in the U.S. grew almost five times faster than the population as a whole. Between 2000 and 2010, the 65+ population grew from 15.1 percent of the U.S. population to 16.8 percent (to 55.8 million people) between 2010 and 2020 (U.S. Census Bureau, 2020). Given this substantial growth, the mobility patterns of older travelers are consequential but have only been lightly studied post-pandemic. To address this gap, this research study analyzed data from the National Household Travel Surveys (NHTS) for 2001, 2009, 2017, and 2022 on the travel behavior of older adults in their 60s, 70s, and up compared with middle-aged and younger travelers.

policy brief

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

Publication Date

March 1, 2025

Author(s)

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

Abstract

During the COVID-19 pandemic, daily travel per person declined significantly in the U.S as activities that required leaving home were increasingly replaced by information and communication technologies (ICTs), such as smartphones, personal computers, streaming services, and social media. Trips for most purposes declined drastically in the spring of 2020 at the start of the pandemic, and public transit use in particular plummeted. With most of the disruptions of the pandemic over by early 2022, this research study investigated whether the travel effects of COVID-19 have persisted, especially among young adults (defined as those between the ages 15-29).

The research focused on youth, as any long-term shifts in their travel behavior might persist for decades. These younger travelers are transitioning to adulthood by obtaining drivers’ licenses, joining the workforce, living independently, and so on. Youth travel may be affected differently by the pandemic than older adults as they are more likely to substitute ICTs for travel, so the study examined how youth travel patterns and trends compare to those of middle-aged adults post-pandemic.

policy brief

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

Publication Date

March 1, 2025

Author(s)

Samuel Speroni, Brian D. Taylor

Abstract

The COVID-19 pandemic accelerated an ongoing trend of Americans spending more time at home and less time engaged in activities away from home. This shift in travel behavior has significant implications for cities, transportation systems, economics, and even mental health. To better understand this trend, this research project examined how people in the U.S. spend their time pre-pandemic, mid-pandemic, and post-pandemic using data from the American Time Use Survey, with a focus on work, leisure, and travel behavior.