published journal article
Real-time hazardous traffic condition warning system: Framework and evaluation
IEEE Transactions on Intelligent Transportation Systems
Publication Date
January 1, 2005
Archives: Research Products
conference paper
Contextualizing Young Driver Lived Experiences of Riding with an Impaired Driver and Driving Impaired on Mental Well-Being: A Qualitative Study
Transportation Research Board 103rd Annual Meeting
Publication Date
January 1, 2024
Author(s)
Kaigang Li, Deepa Camenga, Barbara Banz, Vanessa Zuniga, Candice Grayton, Ronald Iannotti, Federico E. Vaca
Suggested Citation
Kaigang Li, Deepa Camenga, Barbara Banz, Vanessa Zuniga, Candice Grayton, Ronald Iannotti and Federico Vaca (2024) “Contextualizing Young Driver Lived Experiences of Riding with an Impaired Driver and Driving Impaired on Mental Well-Being: A Qualitative Study”. Transportation Research Board 103rd Annual Meeting.
policy brief
Advanced Low-NOx Compressed Natural Gas Engines in Medium- and Heavy-Duty Vehicles Are Poised to Deliver Air Quality Benefits and Advance California’s Climate Goals
Publication Date
June 1, 2017
Abstract
Recent commercialization of advanced low-nitrogen oxides (NOx) Compressed Natural Gas (CNG) engines for medium- (MDV) and heavy-duty (HDV) vehicles has garnered significant interest due to the potential air quality benefits. Further, utilizing renewable natural gas (RNG) in advanced CNG engines from sources such as biomass and/ or biogas can achieve reductions in greenhouse gas (GHG) relative to using petroleum fuels and fossil CNG. However, the regional air quality and GHG reduction benefits of large‐scale deployment of advanced CNG trucks are currently unclear. Further, more information is required regarding RNG production potential from California instate biofuel resources, including potential supply volumes and production pathways that provide maximum GHG reductions. The UC Irvine Advanced Power and Energy Program assessed the air quality and GHG implications of transitioning to advanced CNG engines in MDVs and HDVs in California by developing and comparing different future adoption scenarios. The research team also leveraged prior research of biogas and biomass resources in California to consider different options for producing RNG in-state. Key findings from this research are highlighted in the following section.
Suggested Citation
Michael MacKinnon, Brendan Shaffer, Alejandra Cervantes and G. Scott Samuelsen (2017) Advanced Low-NOx Compressed Natural Gas Engines in Medium- and Heavy-Duty Vehicles Are Poised to Deliver Air Quality Benefits and Advance California’s Climate Goals. Policy Brief. Available at: https://escholarship.org/uc/item/37b8s5dj (Accessed: October 11, 2023). policy brief
Using a “Bathtub Model” to Analyze Travel Can Protect Privacy While Providing Valuable Insights
Publication Date
January 1, 2025
Associated Project
Author(s)
Abstract
Transportation agencies increasingly rely on detailed trip data to analyze traffic patterns and plan infrastructure improvements. However, traditional data collection methods require extensive personal information about travelers’ origins, destinations, and routes, raising serious privacy concerns. Current “big data” approaches can track individual movements with alarming precision, often without explicit consent. As privacy regulations tighten and public concerns grow, transportation planners need alternative methods that balance analytical needs with privacy protection. To address this challenge, the research team evaluated the “bathtub model” as a privacy-preserving alternative to traditional traffic data collection methods. This simple, network-level approach treats all trips in a region as part of one system. Instead of tracking each person’s path, a bathtub model represents trips by how much distance they have left to travel. This allows for analyzation of network performance while protecting privacy.
Suggested Citation
Wen-Long Jin and Joseph Lo (2025) Using a “Bathtub Model” to Analyze Travel Can Protect Privacy While Providing Valuable Insights. Policy Brief UC-ITS-2022-45. UC ITS / ITS-Irvine. Available at: https://doi.org/10.7922/G2D798TX (Accessed: November 3, 2025).Related Publications
Preprint Journal Article |
Sep 2023
Priority Queue Formulation of Agent-Based Bathtub Model for Network Trip Flows in the Relative Space
conference paper
More Dedicated Vehicles or Crowdsourced Couriers? A Strategic Capacity Planning Problem in Last-mile Crowdsourced Delivery
102nd Transportation Research Board Annual Meeting 2023
Publication Date
January 1, 2023
Author(s)
Suggested Citation
Dingtong Yang and Michael F. Hyland (2023) “More Dedicated Vehicles or Crowdsourced Couriers? A Strategic Capacity Planning Problem in Last-mile Crowdsourced Delivery”. 102nd Transportation Research Board Annual Meeting 2023. published journal article
Measuring the inconvenience of operating an alternative fuel vehicle
Transportation Research Part D: Transport and Environment
Publication Date
March 1, 2014
Author(s)
Suggested Citation
Jee Eun Kang and Will W. Recker (2014) “Measuring the inconvenience of operating an alternative fuel vehicle”, Transportation Research Part D: Transport and Environment, 27, pp. 30–40. Available at: 10.1016/j.trd.2013.12.003. published journal article
Particulate matter, traffic-related air pollutants, and circulating C-reactive protein levels: The Multiethnic Cohort Study
Environmental Pollution
Publication Date
September 1, 2023
Author(s)
Meera Sangaramoorthy, Johnny Yang, Chiuchen Tseng, Jun Wu, Beate Ritz, Timothy V. Larson, Scott Fruin, Daniel O. Stram, Seri Park, Adrian A. Franke, Lynne R. Wilkens, Jonathan M. Samet, Loïc Le Marchand, Salma Shariff-Marco, Christopher A. Haiman, Anna H. Wu, Iona Cheng
Abstract
Inhaled particles and gases can harm health by promoting chronic inflammation in the body. Few studies have investigated the relationship between outdoor air pollution and inflammation by race and ethnicity, socioeconomic status, and lifestyle risk factors. We examined associations of particulate matter (PM) and other markers of traffic-related air pollution with circulating levels of C-reactive protein (CRP), a biomarker of systemic inflammation. CRP was measured from blood samples obtained in 1994–2016 from 7,860 California residents participating in the Multiethnic Cohort (MEC) Study. Exposure to PM (aerodynamic diameter ≤2.5 μm [PM2.5], ≤10 μm [PM10], and between 2.5 and 10 μm [PM10-2.5]), nitrogen oxides (NOx, including nitrogen dioxide [NO2]), carbon monoxide (CO), ground-level ozone (O3), and benzene averaged over one or twelve months before blood draw were estimated based on participants’ addresses. Percent change in geometric mean CRP levels and 95% confidence intervals (CI) per standard concentration increase of each pollutant were estimated using multivariable generalized linear regression. Among 4,305 females (55%) and 3,555 males (45%) (mean age 68.1 [SD 7.5] years at blood draw), CRP levels increased with 12-month exposure to PM10 (11.0%, 95% CI: 4.2%, 18.2% per 10 μg/m3), PM10-2.5 (12.4%, 95% CI: 1.4%, 24.5% per 10 μg/m3), NOx (10.4%, 95% CI: 2.2%, 19.2% per 50 ppb), and benzene (2.9%, 95% CI: 1.1%, 4.6% per 1 ppb). In subgroup analyses, these associations were observed in Latino participants, those who lived in low socioeconomic neighborhoods, overweight or obese participants, and never or former smokers. No consistent patterns were found for 1-month pollutant exposures. This investigation identified associations of primarily traffic-related air pollutants, including PM, NOx, and benzene, with CRP in a multiethnic population. The diversity of the MEC across demographic, socioeconomic, and lifestyle factors allowed us to explore the generalizability of the effects of air pollution on inflammation across subgroups.
Suggested Citation
Meera Sangaramoorthy, Juan Yang, Chiuchen Tseng, Jun Wu, Beate Ritz, Timothy V. Larson, Scott Fruin, Daniel O. Stram, Sung-shim Lani Park, Adrian A. Franke, Lynne R. Wilkens, Jonathan M. Samet, Loïc Le Marchand, Salma Shariff-Marco, Christopher A. Haiman, Anna H. Wu and Iona Cheng (2023) “Particulate matter, traffic-related air pollutants, and circulating C-reactive protein levels: The Multiethnic Cohort Study”, Environmental Pollution, 332, p. 121962. Available at: 10.1016/j.envpol.2023.121962. conference paper
Sharing is caring: Dynamic autonomous vehicle fleet operations under demand surges
Proceedings of the 97th annual meeting of the transportation research board
Publication Date
January 1, 2018
Author(s)
Michael Hyland, Hani Mahmassani
Abstract
Given the emergence and growth of ridesourcing companies, the forthcoming introduction of fully- autonomous vehicles (AVs), and the projected positive impact of AVs on the growth of mobility services, this paper aims to analyze the operational efficiency of two on-demand AV-enabled mobility services (AVeMSs). Specifically, the study compares an AV-enabled shared-ride service, with an AV-enabled traditional ridesourcing (i.e. no shared-rides) service, in terms of handling demand surges, when fleet size is fixed. The authors hypothesize that shared-ride service will significantly outperform traditional ridesourcing service because as demand increases with shared-ride service, the number of feasible shared-ride opportunities increases, effectively increasing the service rate of the shared-ride fleet. To test this hypothesis, the authors employ a dynamic agent-based simulation of travelers, AVs, and an AV fleet operator. The underlying AV fleet control problem is highly-dynamic and stochastic, as traveler requests are unknown to the fleet operator a priori. To solve the dynamic and stochastic optimization problem, the AV fleet operator repeatedly re-solves an online AV-traveler assignment problem based on the current state the system. The simulation results illustrate that under various experimental settings, shared-ride service significantly outperforms ridesourcing service in terms of handling demand surges. At low demand levels, traveler wait times are similar for shared-ride and ridesourcing services. However, as demand increases, average traveler wait times increase more rapidly under ridesourcing service. The results suggest shared-ride service allows fleet operators to better handle demand surges.
Suggested Citation
Michael F. Hyland and Hani S. Mahmassani (2018) “Sharing is caring: Dynamic autonomous vehicle fleet operations under demand surges”, in Proceedings of the 97th annual meeting of the transportation research board, p. 16p. published journal article
Adaptive Self-Learning Framework for Resilient Vehicle Classification Through the Integration of Inductive Loops and LiDAR Sensors
IEEE Open Journal of Intelligent Transportation Systems
Publication Date
January 1, 2025
Associated Project
Author(s)
Suggested Citation
Yiqiao Li, Andre Y. C. Tok and Stephen G. Ritchie (2025) “Adaptive Self-Learning Framework for Resilient Vehicle Classification Through the Integration of Inductive Loops and LiDAR Sensors”, IEEE Open Journal of Intelligent Transportation Systems, 6, pp. 768–780. Available at: 10.1109/OJITS.2025.3575808.Related Publications
conference paper
Land Use Regulation and Housing
2022 APPAM Fall Research Conference
Publication Date
January 1, 2022
Author(s)
Nicholas Marantz, Leah Brooks