research report

Microsimulation Modeling of High Occupancy Toll (HOT) Concept in HOV Lanes

Abstract

This project developed a new HOV driver behavioral model that incorporates an access preference/choice model for examining travel time savings and a traffic model for calculating the acceptable gap to get in/out of buffer-separated HOV lane facilities. The model is incorporated into the Paramics simulator as a plug-in developed through API (Application Programming Interface) programming. In order to extend its capability for calibration and implementation, several user-specified parameters were incorporated during the model development process, including ingress and egress points selection control, and provision traffic information updates. The parameters of the model were tested and evaluated using both a sample, idealized, segment of freeway as well as a simulation network of the SR-57 freeway in Orange County, California. Sensitivity analyses were performed to evaluate the reasonableness of the model; the freeway network was further investigated for model validation purposes. The results demonstrate the reasonableness of the proposed model under various traffic conditions. The proposed model also was demonstrated to better capture the weaving maneuvers observed on the SR-57 freeway.

Suggested Citation
Will Recker, Lianyu Chu and Shin-Ting Jeng (2009) Microsimulation Modeling of High Occupancy Toll (HOT) Concept in HOV Lanes. Research Report CA10-1043. ITS-Irvine. Available at: https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/f0017237-final-report-task-1043.pdf.

Phd Dissertation

Novel Vulnerability Discoveries, Measurements, and Attack Designs for Safety-Critical Autonomous Systems from Practicality Perspectives

Publication Date

January 1, 2024

Author(s)

Abstract

Autonomous systems, such as autonomous driving (AD), rely heavily on real-time perception systems to detect and interpret their surroundings, such as traffic cones, pedestrians, traffic signs, vehicles, etc. These perception systems predominantly employ Deep Neural Networks (DNNs) for tasks such as real-time object detection due to their superior performance. However, DNNs are inherently vulnerable to adversarial attacks—maliciously crafted inputs designed to cause the DNNs to malfunction. Given the safety- and mission-critical nature of autonomous systems, it is crucial to systematically investigate the potential security vulnerabilities of these systems in real-world settings. So far, one of the most general yet crucial limitations for prior research works in this area is their limited practicality in real-world autonomous system setups, either due to their sole focus on the AI component alone, which makes it non-trivial to transfer their component-only attack effects to the system level, or due to their research scopes limited to academic prototypes instead of real-world systems. For example, almost all prior adversarial attacks on Traffic Sign Recognition (TSR) systems have only assessed the effects on academic TSR models, leaving the impacts on real-world commercial TSR systems largely unexplored. While a few recent works have attempted to evaluate the impact on commercial TSR systems, these efforts are typically confined to a single vehicle model, sometimes even an unidentified one, raising questions about both the generalizability and representativeness of their findings. In this dissertation, I present a suite of research efforts toward novel vulnerability discoveries, measurements, and attack designs for safety-critical autonomous systems from practicality perspectives. By systematically discovering and understanding the security vulnerabilities at both the DNN model level and autonomous system level, these research efforts aim to provide new and useful insights that can inspire further exploration of this largely under-explored aspect in this research area.

Suggested Citation
Ningfei Wang (2024) Novel Vulnerability Discoveries, Measurements, and Attack Designs for Safety-Critical Autonomous Systems from Practicality Perspectives. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991035677822804701.

Preprint Journal Article

Beyond Infrastructure: Patterns of Environmental Justice and Multi-Level Governance in Greater Los Angeles Transportation and Hazard Planning

Abstract

This study evaluates how environmental justice principles are integrated into transportation and hazard plans across multiple levels of jurisdictions in Greater Los Angeles, revealing how the multi-level governance framework shapes planning practices for environmental justice integration across levels and over time. A content analysis was conducted on 16 transportation, hazard preparedness, climate action, and racial equity plans to develop a scoring methodology. Through comparison the study identified patterns and factors contributing to effective environmental justice integration in transportation and hazard planning. Findings show that although infrastructure (transportation and hazard) plans achieve higher environmental justice integration on average than other plans after 2019, some subdimensions – like recognition justice – remain less integrated. Curiously, the positive trend between environmental justice and multi-level governance observed for climate action and racial equity plans is not observed for infrastructure plans, suggesting greater nuance among the strategies that lead to its successful integration in infrastructure planning.

conference paper

A Choice Experiment Survey of Drayage Fleet Operator Preferences for Zero-Emission Trucks

Proceedings, 104th Annual Meeting of the Transportation Research Board

Abstract

Many U.S. states are supporting the transition of the heavy-duty vehicle (HDV) sector to zero-emission vehicles (ZEVs), with California leading the way through its policy and regulatory initiatives. Within various HDV fleet segments, California’s drayage fleets face stringent targets, requiring all vehicles newly registered in the Truck Regulation Upload, Compliance, and Reporting System to be ZEVs starting January 2024, and all drayage trucks in operation to be zero-emission by 2035. Understanding fleet operator behavior and perspectives is crucial for achieving these goals; however, it remains a critical knowledge gap. This study investigates the preferences and influencing factors for ZEVs among drayage fleet operators in California. We conducted a stated preference choice experiment survey, developed based on previous qualitative studies and literature reviews. With participation from 71 fleets of various sizes and alternative fuel adoption status, we collected 648 choice observations in a dual response design, consisting of a forced choice between ZEVs and a free choice between ZEVs and status quo alternatives. Multinomial logit model analyses revealed driving range and purchase costs as significant factors for ZEV adoption, with charging facility construction costs also critical in hypothetical choices between ZEVs and status quo alternatives. Fleet or organization size also influenced ZEV choices, with large fleets more sensitive to operating costs and small organizations more sensitive to off-site stations. These findings enhance our understanding in this area and provide valuable insights for policymakers dedicated to facilitating the transition of the HDV sector to zero-emission.

Suggested Citation
Youngeun Bae, Stephen Ritchie and Craig R Rindt (2025) “A Choice Experiment Survey of Drayage Fleet Operator Preferences for Zero-Emission Trucks”, in Proceedings, 104th Annual Meeting of the Transportation Research Board. Washington, D.C..

conference paper

Leveraging Food Delivery Programs as a Community Resilience Resource: A Demand-Driven Spatial and Temporal Analysis of Need

Transportation Research Board 103rd Annual Meeting

Publication Date

January 1, 2024

Author(s)

G Bella, Elisa Borowski, A Stathopolous
Suggested Citation
G Bella, Elisa Borowski and A Stathopolous (2024) “Leveraging Food Delivery Programs as a Community Resilience Resource: A Demand-Driven Spatial and Temporal Analysis of Need”. Transportation Research Board 103rd Annual Meeting.

research report

Impact of Highway Capacity and Induced Travel on Passenger Vehicle Use and Greenhouse Gas Emissions

Suggested Citation
Susan Handy and Marlon Boarnet (2014) Impact of Highway Capacity and Induced Travel on Passenger Vehicle Use and Greenhouse Gas Emissions. Research Report. ITS-Irvine. Available at: https://ww2.arb.ca.gov/sites/default/files/2020-06/Impact_of_Highway_Capacity_and_Induced_Travel_on_Passenger_Vehicle_Use_and_Greenhouse_Gas_Emissions_Technical_Background_Document.pdf.

policy brief

Understanding How Caregivers Travel Can Help Strengthen Families and Inform More Equitable Transportation Policies

Abstract

In communities like California’s Antelope Valley, caregivers (especially single parents, parents of children with disabilities, and those with limited financial or social support) face significant mobility barriers. Sparse and unreliable public transit, long travel times, and the high cost of driving make it difficult to access healthcare, work, and community resources. These barriers can worsen caregiver exhaustion, distress, and social isolation and contribute to missed healthcare and family support appointments.

conference paper

Analysis of PM and NOx train emissions in the alameda corridor, California

Proceedings of the 88th annual meeting of the transportation research board

Abstract

The Alameda corridor provides a crucial rail link for moving freight in and out of the Ports of Los Angeles and Long Beach, also known as the San Pedro Bay Ports (SPBP). While the benefits of this trade are enjoyed by the whole nation, the associated air pollution costs are born mostly by the people who live in the vicinity of the Alameda corridor and the two freeways (the I-710 and the I-110) that serve the Ports. Although they are more energy efficient than trucks, trains contribute heavily to regional air pollution; in addition, rail traffic in the South Coast Air Basin is projected to almost double in the next twenty years. This paper presents an analysis of the emissions and the dispersion of PM and NOx emitted by train operations in and around the Alameda corridor. We find spatial and temporal variations in the dispersion of these pollutants, which justifies our approach. Moreover, the railyards in our study area are responsible for the bulk of PM and NOx emissions (compared to line haul operations). While PM emissions from train operations contribute only a fraction of the recommended maximum concentration, NOx emissions go over recommended guidelines in different areas. The affected population is mostly Latino or African American. Our approach is also useful for better understanding trade-offs between truck and rail freight transport.

Suggested Citation
Mana Sangkapichai, Jean-Daniel Saphores, Stephen G. Ritchie, Soyoung You and Gunwoo Lee (2009) “Analysis of PM and NOx train emissions in the alameda corridor, California”, in Proceedings of the 88th annual meeting of the transportation research board, p. 19p. Available at: https://escholarship.org/uc/item/91v8j6hk.

conference paper

Driver’s License for Undocumented Immigrants and Bus Ridership in Orange County, CA

Transportation Research Board 103rd Annual Meeting

Publication Date

January 1, 2024
Suggested Citation
Farzana Khatun and Jean-Daniel Saphores (2024) “Driver’s License for Undocumented Immigrants and Bus Ridership in Orange County, CA”. Transportation Research Board 103rd Annual Meeting.

published journal article

Structural modeling of COVID-19 spread in relation to human mobility

Transportation Research Interdisciplinary Perspectives

Publication Date

March 1, 2022

Author(s)

Rezwana Rafiq, Tanjeeb Ahmed, Md Yusuf Sarwar Uddin

Abstract

Human mobility is considered as one of the prominent non-pharmaceutical interventions to control the spread of the pandemic (positive effect from mobility to infection). Conversely, the spread of the pandemic triggered massive changes to people’s daily schedules by limiting their movement (negative effect from infection to mobility). The purpose of this study is to investigate this bi-directional relationship between human mobility and COVID-19 spread across U.S. counties during the early phase of the pandemic when infection rates were stabilizing and activity-travel behavior reflected a fairly steady return to normal following the drastic changes observed during the pandemic’s initial shock. In particular, we applied Structural Regression (SR) model to investigate a bi-directional relationship between COVID-19 infection rate and the degree of human mobility in a county in association with socio-demographic and location characteristics of that county, and state-wide COVID-19 policies. Combining U.S. county-level cross-sectional data from multiple sources, our model results suggested that during the study period, human mobility and infection rate in a county both influenced each other, but in an opposite direction. Metropolitan counties experienced higher infection and lower mobility than non-metropolitan counties in the early stage of the pandemic. Counties with highly infected neighboring counties and more external trips had a higher infection rate. During the study period, community mitigation strategies, such as stay at home order, emergency declaration, and non-essential business closure significantly reduced mobility whereas public mask mandate significantly reduced infection rates. The findings of this study will provide important insights to policy makers in understanding the two-way relationship between human mobility and COVID-19 spread and to derive mobility-driven policy actions accordingly.

Suggested Citation
Rezwana Rafiq, Tanjeeb Ahmed and Md Yusuf Sarwar Uddin (2022) “Structural modeling of COVID-19 spread in relation to human mobility”, Transportation Research Interdisciplinary Perspectives, 13, p. 100528. Available at: 10.1016/j.trip.2021.100528.