New Methods for Integrating “Discrimination Effects” and Travel Demand Modeling

Status

Complete

Project Timeline

September 20, 2022 - March 31, 2025

Principal Investigator

Campus(es)

UCLA

Project Summary

Advancing the tools needed for equity analysis of transportation investments requires new frameworks that consider the conditions of vulnerable communities and link to travel choice behavior measurement, transportation systems infrastructure, and policy. Large-scale urban travel demand models (made up of a system of linked discrete choice models) are widely used to evaluate the costs and benefits of transportation investments and are employed during the transportation decision-making process). Yet, absent from this classic framework is the role that discrimination plays in constraining opportunity spaces for certain travelers, which then skews assessments of transportation costs and benefits and drives inequitable and harmful transportation investments.

This research project will develop a methodological framework for travel demand modeling that explicitly integrates social-political attitudes, such as discrimination in transport services like ride hailing or in economic activity opportunities such as the labor market. This new framework requires new approaches of latent variable measurement of spatially varying discrimination effects, and development of a choice set generation process that links discrimination with restriction of opportunities. Developing methods to integrate social-political attitudes with the travel behavior modeling framework requires innovation in the measurement of latent spatial discrimination effects and how best to associate these effects with the choice generation process. The required research activities include a literature and data review, testing of approaches for integrating discrimination effects in travel choice models, estimating two-mode destination models for LA County, and performing a series of statistical and model checking tests.

Road Infrastructure Resilience Improvement for Wildfire Hazards

Status

In Progress

Project Timeline

February 3, 2025 - June 30, 2027

Principal Investigator

Project Summary

The recent wildfires in Los Angeles County have exposed severe vulnerabilities in the region’s road network, especially in hillside and canyon neighborhoods. These areas often feature circuitous, poorly connected street layouts with narrow roads and limited evacuation routes, creating dangerous bottlenecks during emergencies. In the January 2025 wildfires, gridlocked traffic at critical choke points forced residents to abandon vehicles, further complicating evacuation efforts and delaying emergency responders. These challenges underscore the urgent need to address inadequate street connectivity in wildfire-prone areas. Climate change-driven increases in wildfire frequency and intensity exacerbate these risks by raising the likelihood of extreme events that outpace current evacuation and response capabilities. Existing research on wildfire hazards often focuses on evacuation strategies or overall system resilience. Still, it rarely examines how street network design impacts evacuation efficiency and wildfire resilience at a network-wide scale. Furthermore, traditional risk-based approaches fail to consider cascading impacts on interconnected road systems

To tackle these issues, this project has initiated hyperlocal data collection in wildfire-affected regions of Los Angeles using a cutting-edge mobile mapping platform equipped with a Kaarta device. This system captures high-resolution LiDAR and panoramic imagery, enabling precise assessments of road widths, connectivity, and vulnerabilities in real-world conditions. By integrating wildfire simulation, connectivity analysis, and resilience assessment to prioritize retrofitting needs, this study will provide actionable recommendations for evacuation planning and infrastructure resilience in Los Angeles County.

After the Crash: Post-Collision Travel Behavior and Safety Perceptions

Status

Complete

Project Timeline

October 1, 2023 - September 30, 2024

Principal Investigator

Project Team

Jesus M. Barajas, Md. Musfiqur Rahman Bhuiya

Project Summary

Over the past five years in California, there were an average of over 3,800 fatalities, almost 15,900 serious injuries, and more than 233,100 minor injuries each year resulting from vehicular collisions. These collisions disproportionately affect individuals from socioeconomically disadvantaged backgrounds, including people with disabilities. Despite the physical and mental harm suffered by collision victims, little is known about how these incidents impact their travel behaviors, such as travel frequency and mode choices. Reduced travel frequency could potentially harm socioeconomic equity, as victims who travel less may be less active in the economy as workers or consumers. This effect is likely to be more pronounced for people with disabilities, who already face disadvantages in terms of access and mobility. Furthermore, shifts away from public or active transportation options in favor of other modes may undermine the other state goals, including reducing greenhouse gas emissions from transportation.

Interviews with professionals who work with individuals affected by road collisions reveal that there is no systematic collection of data regarding the effects of such collisions on individual travel behavior. This project aims to fill this gap by conducting focus groups with individuals who have experienced road collisions. The focus will be on their safety concerns and transportation priorities. Specifically, this project aims to address: i) how collisions or near misses impact travel frequencies and mode choices, especially for individuals with disabilities, and ii) how experiences with collisions or near misses make people more likely to use single-occupancy vehicular modes like driving, riding as a passenger, or using taxis, ride-hailing services, or paratransit. This research builds upon an ongoing project where the researchers are collaborating with community-based organizations across California and medical professionals who work with road collision survivors. The goal is to understand the transportation concerns expressed by these individuals. This project will conduct six focus groups. Participants will generate ideas and comprehensively explore the issues and concerns raised. In each session, participants will be asked about their travel habits, transportation concerns, and specific road safety worries. The insights gathered will inform policy recommendations related to road safety, transportation equity, and reducing greenhouse gas emissions. They will also guide future research efforts, including a more extensive survey to better understand how experiences with road collisions affect travel behavior.

Investigating Unmet Travel Needs in Disadvantaged and Rural Communities: Can sustainable transportation meet these needs?

Status

Complete

Project Timeline

May 1, 2025 - September 30, 2025

Principal Investigator

Project Team

Jesus M. Barajas, Weijing Wang

Campus(es)

UC Davis

Project Summary

Disadvantaged, low-income, rural, and tribal communities, often collectively referred to as underserved or priority populations, have less access to transportation infrastructure, face more barriers in getting around, and are underrepresented in the transition to sustainable and electric transportation. Using results from a California wide questionnaire survey that overrepresents priority populations, we will investigate unmet and suppressed travel needs, whether sustainable transportation can meet those needs, and what policy, practice, and infrastructure interventions can support sustainable transportation in these communities. The research will give insight into communities that are typically not included in large numbers in travel surveys, which means their transportation needs, unmet and suppressed travel needs, and any barriers they face in adopting sustainable transportation are as not well understood in quantitative research. The results will inform policy, practice, and infrastructure programs that aim to create a more equitable and just transportation system by providing insight on the nature of unmet and suppressed travel, including types of destinations (e.g., work, education, health) populations cannot access or have difficulties in accessing, their preferred mode to reach that location, and whether sustainable transportation can meet these unmet needs (in addition to meeting currently met needs).

published journal article

The social life of the sidewalk: tracing the mobility experiences of youth in Westlake, Los Angeles

Abstract

Although many young people travel independently in the city, transportation research seldom considers the experiential qualities of their routes, focusing instead on the functional aspects of mode choice. More in-depth understanding of how adolescents experience, negotiate, and perceive everyday mobility can support informed design, policy, and planning interventions to make these journeys safer and more enjoyable. This study explores the mobility experiences of 28 youth aged 11 to 15 as they travel to after-school activities in Westlake: a dense, underserved Los Angeles neighborhood. We use the concept of ‘sidewalk ecologies’ to investigate the spatially-situated social and material features that shape mobility experiences, and employ a range of interdisciplinary, youth-centered, mobile methods including thick mapping and walk-along interviews. We uncover how youth negotiate travel through adaptation rather than avoidance, how they develop agency to travel without supervision, and how social and material conditions create a lack of continuity between safe and enjoyable spaces. These insights inform design and programmatic interventions to enhance mobility for young pedestrians; five propositions for urban planners and designers include tending to the social determinants of safety, reinforcing familiar routes, and demonstrating care for people and place.

published journal article

Spatial analysis and predictive modeling framework of truck parking and idling impacts on environmental justice communities

Abstract

This study introduces a comprehensive modeling framework to analyze truck idling and parking activities, illustrated through a case study in environmental justice communities in Kern County, California. It includes 1) exploratory spatial and cluster analysis to identify hotspots of those truck activities and their influencing factors, and 2) advanced predictive models, particularly the Cross-Validated Random Forests model, to predict and investigate critical factors influencing truck idling time, parking search time, and inferred truck parking demand. The results reveal that the percentage of heavy-duty trucks and the specific land use influence truck idling time. For parking search time, key predictors include distance to major roads and employment in certain industries. The inferred truck parking demand model underscores the impact of commercial land use areas, proximity to major roads, and socioeconomic factors. These findings enable the identification of hotspots for truck idling and parking searches, facilitating targeted interventions such as optimizing land use planning, improving infrastructure around major roads, and enhancing parking facilities in commercial zones. Integrating spatial, socioeconomic, and GPS aggregate data, the methodology provides a scalable framework applicable to other regions facing similar challenges through data-driven planning and policy initiatives.

Is Micromobility Being Used in Place of Car Trips?

Status

Complete

Project Timeline

October 1, 2022 - April 1, 2024

Principal Investigator

Project Team

Hossain Mohiuddin, Hossain Mohiuddin

Project Summary

Since 2017, there has been massive growth in micromobility trips (i.e., trips taken by electric bike-share and scooter-share). To understand the extent to which micromobility services such as bike-share and scooter-share are replacing driving, this project explores the trip-chaining patterns of micromobility users. The project uses travel diary data collected from micromobility users in 48 cities across the US. Results point to a considerable portion of car owners leaving their cars at home when using micromobility, suggesting that, for a subset of users, micromobility can form part of a car-free or car-light day of travel, despite having a car available.

Which Communities Suffer the Most from Neighborhood Severance Caused by Freeways?

Status

Complete

Project Timeline

September 20, 2021 - December 31, 2022

Principal Investigator

Project Summary

The racial legacy of freeways has come into stark focus in the past year. A recent Los Angeles Times article calls the region’s freeway system “one of the most noxious monuments to racism and segregation in the country.” A key feature of past freeways construction has been neighborhood severance. Freeways disrupt the neighborhood street grid, creating particular hardships for pedestrians who must take circuitous routes to access transit and to walk to stores, schools, and other destinations. The impacts of disconnected streets on walking and public health are well documented, but the environmental justice dimension of connectivity has remained unexplored, as has the link between street connectivity and local planning efforts. Reducing neighborhood severance is also a key goal in Caltrans’ 2017 bicycle and pedestrian plan, Towards an Active California. The plan commits the agency to identify and improve highway crossings and to prioritize improvements based on equity criteria. The research team will test whether Black, Indigenous, People of Color (BIPOC) communities suffer greater neighborhood severance effects based on four measures of connectivity: local street connectivity, connectivity for transit access, the number of freeway crossings per mile, and the quality of those crossings (e.g., pedestrian comfort). The first two measures are based on street characteristics such as circuity and the proportion of streets that are dead-ends. The project team will also examine the strength of the relationship between these four connectivity measures and the race/ethnic composition of the neighborhoods, based on 2020 Census block-level demographic data, and on the age of the constructed freeways, to determine whether planners have become more attuned to severance effects over time. Finally, the researchers will consider where new or upgraded crossings would yield the greatest connectivity benefits, particularly in BIPOC communities, by simulating the addition of new crossings and the removal of existing crossings, to determine which improvements have the greatest potential to reconnect street networks and improve pedestrian and bicycle access to transit.

Looking Abroad to Understand the Potential Impacts of California High-Speed Rail on Economic Development, Land Use Patterns, and Future Growth of Cities

Status

Complete

Project Timeline

September 20, 2021 - September 30, 2023

Principal Investigator

Project Team

Basar Ozbilen, Giovanni Circella, Maria Carolina Lecompte, Andrew Jarnagin, Lucia Rossignol

Project Summary

New transportation networks facilitate mobility and may also spur economic development. This was the case with the construction of railway and highway networks in the U.S. during the late 19th and mid-20th century, respectively. Over the past decades, a new transportation technology—high-speed rail (HSR)—has had a profound impact on urban-regional accessibility and intercity travel across Europe and East and South-East Asia. A growing literature shows that HSR systems can also benefit local and regional economies. But the economic and spatial impacts of HSR have been varied and are largely contingent on a variety of factors, as well as local planning and policy. As California is in the process of building its own HSR network, it is important to review the experience of established HSR networks abroad to understand the possible economic effects that HSR can have on regional and local economies. While the impacts of California’s HSR plan on job creation in local markets (e.g., the construction sector) and on the travel sector (e.g., forecasts for HSR travel demand) have been investigated, the possible indirect impacts on land values, tourism, firm location, and local and regional development, among others, have not garnered enough attention. This study will provide guidance for the development of California HSR by undertaking a comprehensive literature review of the economic impacts of existing HSR systems and conducting case studies of HSR station-cities in Europe. The literature review will identify the prerequisites necessary for certain positive economic outcomes for different types of station-cities. The research team will examine the impacts of HSR on construction jobs, but also on post-construction job growth, firm relocation, residential and commercial development, tourism, and population growth. The team will select several individual case studies representing different city typologies with input from the California High-Speed Rail Authority (CHSRA) and from the study’s advisory panel. The case studies will focus on station-cities that have experienced significant economic benefits since the initiation of HSR to identify how and why these benefits have occurred.

How Post-Pandemic Travel Trends May Affect Public Transit

Status

Complete

Project Timeline

October 1, 2021 - June 30, 2022

Principal Investigator

Project Team

Julene Paul

Project Summary

California’s metropolitan areas have invested heavily in improving and expanding public transit systems over the past half century. But despite demonstrable improvements in transit provision, ridership was eroding in many areas during the dozen years leading up to the COVID-19 pandemic, and in most places and on most systems in California since 2016. But these dips in ridership paled in comparison to the crash in patronage that coincided with the onset of the pandemic. By the fall of 2020, most transit systems had recovered to about half of their pre-pandemic ridership, but transit’s recovery largely stalled there, even as rates of driving, walking, and biking have mostly recovered to pre-pandemic levels. Research has shown that the riders who left transit during the pandemic tended to be higher income, better educated, more likely white or Asian, and had access to private motor vehicles. Spatial patterns of ridership have shifted dramatically as well, with downtowns and other major job centers losing the most riders, and low-income neighborhoods retaining the most riders. In net, the level, timing, and direction of transit travel have changed dramatically. This study draws on previous research on transit usage changes during the pandemic, and supplements previous findings with additional travel data from transit operators and mobile device services to better understand how these new patterns of transit usage are evolving as the pandemic matures and recedes. In addition, this study draws on the findings from companion research on changing work and travel patterns to project likely patterns of transit use and demand in the months and years ahead to help public transit system managers and policy makers prepare for a post-pandemic transit future.