policy brief

3 PM Is the New 5 PM: Post-Pandemic Travel Patterns in Southern California Are Shifting

Abstract

In the spring of 2020, daily travel collapsed as public health measures during the COVID-19 pandemic kept most people at home. Streets were suddenly and eerily empty in cities around the world. Since then, rates of driving, biking, and walking have largely rebounded, roughly returning to pre-pandemic levels. However, public transit use, particularly in the U.S., has been slow to recover and remains mostly well below pre-pandemic levels.The effects of pandemic-influenced changes in activity and travel are not always intuitive. Working from home may reduce the number of commute trips (especially on public transit), but may induce longer commutes when they do occur. Working from home may also free up time for running errands and chauffeuring children. Similarly, online shopping may reduce trips to the store, but it also generates more commercial delivery trips.While previous research has examined pandemic-induced changes in how much and by which modes people travel, when travel occurs has garnered far less attention. Yet the many longer-term changes in personal and commercial activities coming out of the pandemic — such as remote work, online shopping, and video streaming — likely influence the timing of travel. Changes in travel timing also deserve further study because travel peaking — by time of day and day of week — strongly influences traffic congestion, vehicle emissions, and public transit demand

policy brief

Impacts of Freeway Siting on Stockton’s Asian American Community

Abstract

Stockton, California, underwent spatial restructuring in the decades following World War II. State and local government contributed and responded to these changes by implementing connected freeway and urban renewal programs. Xenophobia and racism placed Asian American communities in their path.A major economic hub for California’s agricultural sector, Stockton and the surrounding region had a racially and ethnically diverse population in the mid-1900s, with people of color restricted to the lowest rungs of society. Asian Americans played a major role in the city’s development but were socially, economically, and politically marginalized. Since the mid-1800s and into the 1970s, Asian Americans were targets of multiple forms of discrimination, some shared by other people of color and others unique to Asians, including xenophobic immigration restrictions, prohibitions against owning land, and mass internment.Residential segregation limited their housing options, forcing many to settle in and around downtown. Despite facing racism and having limited resources, Asian Americans were able to form vibrant albeit low-income ethnic enclaves: Chinatown, Japantown, and Little Manila.Government actions initiated, facilitated, and responded to a postwar restructuring of the urban landscape through suburbanization and the abandonment of the central business district. A dramatic expansion of the freeway system made way for urban sprawl. At the same time, Stockton responded to the commercial decline of its downtown by pursuing urban renewal. These coordinated, massive infrastructure programs were linked through a common agenda of “slum clearance” that sought removal of entire neighborhoods. Tragically, the Asian enclaves lay along the path of destruction of both.

research report

Lessons Learned from Abroad: Potential Influence of California High-Speed Rail on Economic Development, Land Use Patterns, and Future Growth of Cities

Abstract

This study discusses the potential economic and development impacts that high-speed rail (HSR) may bring to California. The research reviews the reported impacts of HSR implementation in various countries, particularly in Europe, and case studies of selected HSR station cities in France, Spain, and Italy. The analysis suggests that HSR could bring economic development to the state and stimulate population growth but might eventually lead to gentrification in certain locations. Not all station cities experience the same impacts, and certain conditions may foster greater economic development. Station location and connectivity to downtown areas would be particularly important in influencing these impacts, while peripheral stations would be less able to attract land use development and relocation of activities. The availability of rail service to larger cities (and connections to other major markets) and the coordination with urban planning and policy are key to determining the development of areas around HSR stations. The study indicates that for HSR to bring about desired economic development, the planning and design of stations and services must be integrated with the vision and urban plans of each station city.

research report

Measuring Changes in Air Quality from Reduced Travel in Response to COVID-19

Abstract

The lack of a strong reduction in ambient ozone (O3) concentrations during reduced traffic periods associated with COVID-19 calls into question the conventional wisdom that mobile sources dominate air pollution in California. Fossil-fueled motor vehicles emit oxides of nitrogen (NOx) and volatile organic compounds (VOCs) that are precursors to O3 formation, but the chemical reaction system that forms O3 is complex. The ratio of NOx/VOCs determines if the O3 formation regime is NOx-limited (reducing NOx reduces O3) or NOx-rich (reducing NOx increases O3). This project developed new methods to directly measure O3 chemistry in the atmosphere and applied them over long-term campaigns in multiple California cities to quantify traffic contributions to O3 formation. A seasonal cycle was observed of NOx-rich O3 chemistry during cooler months trending toward NOx-limited chemistry in warmer months. Superimposed on this seasonal cycle was a spatial pattern of NOx-rich chemistry in dense urban cores and NOx-limited chemistry in areas downwind of urban cores. Chemistry-based models with source tagging were also developed to better understand these trends. Seasonal changes to biogenic VOC and gasoline evaporative VOC emissions likely explain the seasonal changes in O3 formation chemistry. Reduced traffic emissions in March 2020 did not reduce O3 concentrations because the chemistry was heavily NOx-rich during the spring season. Extended model predictions suggest that similar traffic reductions could have reduced ambient O3 concentrations in small and intermediate cities if they had occurred in the summer months. Traffic reductions alone would not be sufficient to reduce O3 concentrations in the urban cores of larger cities. Reduced emissions from transportation sources can improve air quality in California, but transportation sources no longer exclusively dominate O3 formation. Future emissions controls should be coordinated across multiple sectors (including transportation) to achieve their objectives.

blog

What Happened to Stockton's First Asian Enclaves?: How the City’s Chinatown, Japantown, and Little Manila Were Razed in the Name of "Progress"

policy brief

Pathways to Autonomy: Supporting Youth Independent Mobility in Westlake, Los Angeles

Abstract

Each day, youth in Los Angeles venture out on their own to move to and from home, school, and after-school activities. Their travels represent important pathways to autonomy, agency, and urban citizenship, which a city can support with safe, pleasant paths that offer reassuring familiarity and opportunities for socializing.

research report

Pathways to Autonomy: Supporting Youth Independent Mobility in Westlake, Los Angeles

Abstract

In this study, the research paper uses the concept of “sidewalk ecologies” to highlight the complex interaction between spatially situated social and material features of sidewalks that influence youth mobility. The research team uses a range of interdisciplinary strategies, emphasizing youth-centered research methods and mapping to capture a rich portrait of the independent travel experiences, perceptions, and ideas of youth, in their own voices. This research was conducted in partnership with Heart of Los Angeles (HOLA), a community-based organization in Westlake that provides after-school programming to thousands of neighborhood youths, and yielded important findings.

research report

Effects of Road Collisions on the Travel Behavior of Vulnerable Groups: Expert Interview Findings

Abstract

The research team interviewed eight subject-matter experts in California in 2023 to understand how travel behavior and priorities may change in response to direct experience with road collisions. Experts represented a variety of perspectives, including medical doctors, advocates for active transportation safety, and advocates for people with disabilities. Their diverse specialties enabled us to capture a variety of concerns without triggering emotionally sensitive areas for people who have directly experienced road collisions. These experts identified common themes, including mental stress from the prospect of returning to driving—especially on freeways, lesser incidence of long-term changes in travel modes after experiencing a collision, dependence on others for rides in private vehicles, and changing routes or times of day of travel when traveling independently. These experts also explained how people’s mode choices are also affected by general concerns about collisions in the news more than by specific personal experiences with near misses. Interview subjects’ spoke of more specific concerns as well. These included but were not limited to, bicyclists using sidewalks instead of bike lanes when both are present, feeling stigmatized from using public transit or paratransit after experiencing a collision, and concerns with motorists treating bicyclists badly. These initial interviews clarify areas of focus and methodology for future qualitative and quantitative studies on the intersection of transportation safety and travel behavior change, particularly as they involve people who have directly experienced road collisions.

research report

The Effects of Truck Idling and Searching for Parking on Disadvantaged Communities

Abstract

This project identifies factors that affect three truck-related parameters: idling, searching for parking, and parking demand. These parameters are examined in communities in Kern County California that have high air pollution levels and are located near transportation corridors, industrial facilities, and logistics centers. Daytime truck idling is concentrated in and around commercial and industrial hubs, and nighttime idling is concentrated around major roads and highway entrances, and exits. Truck idling, searching for parking, and parking demand correlate with shorter distances from freight-related points of interest such as warehouses, increased size of nearby industrial or commercial land use, and proximity to areas of dense population or income inequality. Based on these findings, policy recommendations include targeted anti-idling interventions, improved truck parking facilities, parking systems that provide real-time availability information to drivers, provision of alternate power sources in parking facilities to allow trucks to turn off, cleaner fuels and technologies, enhanced routing efficiency, stricter emission standards, and stronger land-use planning with buffer zones around residential areas.

conference paper

An Exploratory Analysis of Alternative Travel Behaviors of Ride-hailing Users

Abstract

The emergence of ride-hailing, technology-enabled on-demand services such as Uber and Lyft, has arguably impacted the daily travel behavior of users. This study analyzes the travel behavior of ride-hailing users first from conventional person- and trip-based perspectives and then from an activity-based approach that uses tours and activity patterns as basic units of analysis. While tours by definition are more easily identified and classified, daily patterns theoretically better represent overall travel behavior but are simultaneously more difficult to explain. We thus consider basic descriptive analyses for tours and a more elaborate approach, Latent Class Analysis, to describe pattern behavior. The empirical results for tours using data from the 2017 National Household Travel Survey show that 76% of ride-hailing tours can be represented by five dominant tour types with non-work tours being the most frequent. The Latent Class model suggests that ride-hailing users can be divided into four distinct classes, each with a representative activity-travel pattern defining ride-hailing usage. Class 1 was composed of younger, employed people who used ride-hailing to commute to work. Single, older individuals comprised Class 2 and used ride-hailing for midday maintenance activities. Class 3 represented younger, employed individuals who used ride-hailing for discretionary purposes in the evening. Last, Class 4 members used ride-hailing for mode change purposes. Since each identified class has different activity-travel patterns, they will show different responses to policy directives. The results can assist ride-hailing operators in addressing evolving travel needs as users respond to various policy constraints.