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.

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

Assessing the sustainability of last-mile distribution strategies to manage expedited shipping with dynamic and stochastic demand

Publication Date

June 25, 2025

Author(s)

Anmol Pahwa, Miguel Jaller

Abstract

As many e-retailers compete through increasingly consumer-focused services, urban freight faces a critical need for sustainable alternate last-mile distribution practices. While previous research has investigated the performance of various distribution strategies under different planning and network design scenarios, their performance under the dynamic and stochastic conditions inherent to consumer-focused services (e.g., expedited deliveries) is not well understood. This study introduces a dynamic-stochastic last-mile network design (DS-LMND) problem, formulated as a multi-echelon capacitated location routing problem with time-windows (ME-C-LRP-TW), to address this gap. Consequently, this work develops a Monte Carlo simulation–optimization framework integrated with an adaptive large neighborhood search (ALNS) metaheuristic to solve the problem. Using this framework, the authors configure the distribution structure and simulate last-mile operations for each distribution strategy. For these configured distribution structures, this work determines economic viability, environmental efficiency, and social equity – the three pillars of sustainability. Further, the authors determine the impact of demand uncertainties on the sustainability of last-mile distribution through the value of information (VI) and coefficient of variance (CV) metrics. In doing so, this work a) estimates the efficacy of conventional distribution strategy; b) confirms the competitiveness of electric delivery vehicles; c) evaluates the effectiveness of crowdsourced delivery services; d) advances the case for consolidation-based multi-echelon distribution strategies; e) establishes the rationale for customer pickups; and f) develops the use case for drone and robots, to cater to dynamic and stochastic demand with expedited shipping.

policy brief

Early Results on Individual Life Outcomes from the L.A. Mobility Wallet Phase I Pilot Program

Publication Date

May 5, 2025

Author(s)

Madeline Brozen, Tamika Butler, Madeline Wander, Evelyn Blumenberg, Sang-O Kim

Abstract

Universal basic mobility is a growing transportation concept rooted in the belief that everyone should be able to travel to the places they need — and want — to go in ways that best suit their lives and households. Reliable transportation access is essential to quality of life, yet barriers remain, especially for low-income people of color. In 2023, Los Angeles piloted a Mobility Wallet program, providing direct financial support for transportation to low- income travelers. Additional transportation resources may allow participants to expand their travel options, using new travel modes, reaching more destinations and improving their quality of life. This research examined whether and how this occurred, focusing on outcomes for participants during and after the one-year pilot program, drawing on interviews conducted during and after the program.

published journal article

Charging Ahead: Perceptions and Adoption of Electric Vehicles Among Full- and Part-Time Ridehailing Drivers in California

Abstract

California’s SB 1014 (Clean Miles Standard) mandates ridehailing fleet electrification to reduce emissions from vehicle miles traveled, posing financial and infrastructure challenges for drivers. This study employs a mixed-methods approach, including expert interviews (n = 10), group discussions (n = 8), and a survey of full- and part-time drivers (n = 436), to examine electric vehicle (EV) adoption attitudes and policy preferences. Access to home charging and prior EV experience emerged as the most statistically significant predictors of EV acquisition. Socio-demographic variables, particularly income and age, could also influence the EV choice and sensitivity to policy design. Full-time drivers, though confident in the EV range, were concerned about income loss from the charging downtime and access to urban fast chargers. They showed a greater interest in EVs than part-time drivers and favored an income-based instant rebate at the point of sale. In contrast, part-time drivers showed greater hesitancy and were more responsive to vehicle purchase discounts (price reductions or instant rebates at the point of sale available to all customers) and charging credits (monetary incentive or prepaid allowance to offset the cost of EV charging equipment). Policymakers might target low-income full-time drivers with greater price reductions and offer charging credits (USD 500 to USD 1500) to part-time drivers needing operational and infrastructure support.

published journal article

Moving, mapping, imagining: Youth-centered methods for analyzing and envisioning mobility futures

Abstract

Adolescents hold extensive knowledge about their independent travel experiences and aspirations, yet mobility research rarely elevates the voices and visions of youth. This article explores the potential of mobile, map-based, and projective methods to enhance understanding of youth mobility needs and to inform supportive, place-responsive public realm interventions. Based on a participatory research project involving thirty-nine adolescents aged eleven to fifteen in a dense Los Angeles neighborhood, this research demonstrates how moving, mapping, and imagining in collaboration with youth participants can advance justice in both planning processes and in public spaces that support young people’s mobility and urban agency.

policy brief

Evaluating Transportation Equity Data Dashboards

Publication Date

June 1, 2025

Author(s)

Claire McGinnis, Jesus M. Barajas

Abstract

The historical impacts of transportation planning and investment have adversely impacted communities of color and low-income communities. In response, state departments of transportation, metropolitan planning organizations, and local and county governments have begun to address these injustices through plans, policies, and deeper engagement with communities, though work in this area is still nascent. There are a variety of data, tools, and metrics from research and practice that measure the distributional equity of transportation planning and projects to inform equitable solutions.

policy brief

Electric Vehicles Could Reduce Costs for Low-Income Drivers if Structural Barriers are Addressed

Abstract

Battery-electric vehicles (BEVs) are central to California’s strategy to reduce transportation-related emissions; however, low-income households face significant structural barriers to adoption. These barriers include the high upfront purchase costs of new BEVs, limited supply of used BEVs, limited access to home charging, and low awareness of BEVs. To better understand these obstacles and identify effective policy responses, the research team analyzed survey data collected from 2,051 priority population households throughout California between December 2023 and June 2024. The survey asked households about their vehicle purchasing behavior, ownership costs, and socio-demographics.

presentation

Estimating the Magnitude and Impacts of Bike Theft on Bicycling Behavior