published journal article
Microsimulation of flexible transit system designs in realistic urban networks
Transportation Research Record
Publication Date
January 1, 2005
Archives: Research Products
published journal article
The process of information propagation in a traffic stream with a general vehicle headway: A revisit
Transportation Research Part C: Emerging Technologies
Publication Date
June 1, 2010
Author(s)
Bruce (Xiubin) Wang, Teresa M. Adams, Wenlong Jin, Qiang Meng
Suggested Citation
Bruce (Xiubin) Wang, Teresa M. Adams, Wenlong Jin and Qiang Meng (2010) “The process of information propagation in a traffic stream with a general vehicle headway: A revisit”, Transportation Research Part C: Emerging Technologies, 18(3), pp. 367–375. Available at: 10.1016/j.trc.2009.05.011.Preprint Journal Article
Free transit for students to regain ridership: Users and boarding characteristics of LA Metro's GoPass program
Publication Date
October 1, 2025
Author(s)
Abstract
The Los Angeles County Metropolitan Transportation Authority (LA Metro) started in October 2021 the largest free transit pass program in the U.S. to date. Known as GoPass, it serves students from kindergarten to community colleges in Los Angeles County, the most populated county in the U.S. Although many free transit pass programs have been created, few have been analyzed from the point of view of transit agencies (i.e., for the characteristics of their users and their impact on ridership). To address this gap, the research first examines GoPass’ contribution to LA Metro’s bus boardings, before comparing selected characteristics of the students enrolled in GoPass in 2023 with census data. The research finds some opportunities for additional growth, including for female students. To understand GoPass usage, the research estimated a generalized spatial regression model that explains annual GoPass boardings aggregated by census tract (detailed usage data are unavailable to protect the students’ privacy) using a broad range of socioeconomic and built environment variables. The results confirm the presence of strong spatial effects. The research finds that census tracts with more young males, more transit stops, mixed land use, and more participating schools accessible within 30 min by transit have more GoPass boardings. Conversely, the number of GoPass boardings decreases with more access to private vehicles, property crimes, multifamily units, and a higher population density. A better understanding of the characteristics of GoPass users and GoPass usage is useful to improve GoPass and to inform transit agencies interested in creating similar programs.
published journal article
Short-Term Exposure to Ambient Air Pollution and Increased Emergency Room Visits for Skin Diseases in Beijing, China
Toxics
Publication Date
May 1, 2021
Author(s)
Wanzhou Wang, Wenlou Zhang, Jingjing Zhao, Hongyu Li, Jun Wu, Furong Deng, Qingbian Ma, Xinbiao Guo
Abstract
Skin diseases have become a global concern. This study aims to evaluate the associations between ambient air pollution and emergency room visits for skin diseases under the background of improving air quality in China. Based on 45,094 cases from a general hospital and fixed-site monitoring environmental data from 2014–2019 in Beijing, China, this study used generalized additive models with quasi-Poisson regression to estimate the exposure–health associations at lag 0–1 to lag 0–7. PM2.5 and NO2 exposure were associated with increased emergency room visits for total skin diseases (ICD10: L00-L99). Positive associations of PM2.5, PM10, O3 and NO2 with dermatitis/eczema (ICD-10: L20–30), as well as SO2 and NO2 with urticaria (ICD-10: L50) visits were also found. For instance, a 10 μg/m3 increase in PM2.5 was associated with increases of 0.7% (95%CI: 0.2%, 1.2%) in total skin diseases visits at lag 0–5 and 1.1% (95%CI: 0.6%, 1.7%) in dermatitis/eczema visits at lag 0–1, respectively. For PM2.5, PM10 and CO, stronger annual associations were typically observed in the high-pollution (2014) and low-pollution (2018/2019) years. For instance, a 10 μg/m3 increase in PM2.5 at lag 0–5 was associated with increases of 1.8% (95%CI: 1.0%, 2.6%) and 2.3% (95%CI: 0.4%, 4.3%) in total skin disease visits in 2014 and 2018, respectively. Our study emphasizes the necessity of controlling the potential health hazard of air pollutants on skin, although significant achievements in air quality control have been made in China.
Suggested Citation
Wanzhou Wang, Wenlou Zhang, Jingjing Zhao, Hongyu Li, Jun Wu, Furong Deng, Qingbian Ma and Xinbiao Guo (2021) “Short-Term Exposure to Ambient Air Pollution and Increased Emergency Room Visits for Skin Diseases in Beijing, China”, Toxics, 9(5), p. 108. Available at: 10.3390/toxics9050108.
working paper
Performance Indicators for Transit Management
Publication Date
September 5, 1978
Associated Project
Author(s)
Working Paper
UCI-ITS-WP-78-1
Areas of Expertise
Abstract
Transit performance can be evaluated through quantitative indicators. As the provision of efficient and effective transit service are appropriate goals to be encouraged by federal and state governments, these goals are used to develop performance indicators. Three efficiency and four effectiveness indicators are described, together with two overall indicators. These nine indicators are analyzed for comparability utilizing operating and financial data collected from public transit agencies in California. Performance indicators selected for this study should not be viewed as final. Twenty-one performance indicators proposed by previous studies were reviewed. Theoretical considerations and unavailability or unreliability of data caused omission of several useful measures like passenger-miles. Circumstances such as improved data, emphasis upon goals other than efficiency and effectiveness, and local conditions might warrant the inclusion of indicators deleted from this research.
Suggested Citation
Gordon J. Fielding, Roy E. Glauthier and Charles A. Lave (1978) Performance Indicators for Transit Management. Working Paper UCI-ITS-WP-78-1. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/35q3s252.Related Publications
research report |
Dec 1977
Development of performance indicators for transit
published journal article |
Dec 1978
Performance indicators for transit management
Transportation
published journal article
Use of Low-Cost Sensors to Characterize Occupational Exposure to PM2.5 Concentrations Inside an Industrial Facility in Santa Ana, CA: Results from a Worker- and Community-Led Pilot Study
Atmosphere
Publication Date
May 1, 2022
Author(s)
Shahir Masri, Jose Rea, Jun Wu
Abstract
PM2.5 is an air contaminant that has been widely associated with adverse respiratory and cardiovascular health, leading to increased hospital admissions and mortality. Following concerns reported by workers at an industrial facility located in Santa Ana, California, workers and community leaders collaborated with experts in the development of an air monitoring pilot study to measure PM2.5 concentrations to which employees and local residents are exposed during factory operating hours. To detect PM2.5, participants wore government-validated AtmoTube Pro personal air monitoring devices during three separate workdays (5 AM–1:30 PM) in August 2021. Results demonstrated a mean PM2.5 level inside the facility of 112.3 µg/m3, nearly seven-times greater than outdoors (17.3 µg/m3). Of the eight workers who wore personal indoor sampling devices, five showed measurements over 100 μg/m3. Welding-related activity inside the facility resulted in the greatest PM2.5 concentrations. This study demonstrates the utility of using low-cost air quality sensors combined with employee knowledge and participation for the investigation of workplace air pollution exposure as well as facilitation of greater health-related awareness, education, and empowerment among workers and community members. Results also underscore the need for basic measures of indoor air pollution control paired with ongoing air monitoring within the Santa Ana facility, and the importance of future air monitoring studies aimed at industrial facilities.
Suggested Citation
Shahir Masri, Jose Rea and Jun Wu (2022) “Use of Low-Cost Sensors to Characterize Occupational Exposure to PM2.5 Concentrations Inside an Industrial Facility in Santa Ana, CA: Results from a Worker- and Community-Led Pilot Study”, Atmosphere, 13(5), p. 722. Available at: 10.3390/atmos13050722. published journal article
Does mobility matter? The neighborhood conditions of housing voucher holders by race and ethnicity
Housing Policy Debate
Publication Date
January 1, 2005
Author(s)
Abstract
Mobility is one mechanism used to address the federal goals of deconcentrating poverty and minorities. The Housing Choice Voucher Program relies on participants to make residential location decisions consistent with these goals. Our research investigates the level and impact of mobility on the neighborhood quality of voucher holders, their neighborhood conditions by race and ethnicity, and perceived obstacles to mobility within the jurisdiction of a Southern California housing authority. About one-third of the sample moved during the study, and moving resulted in improved neighborhoods for only one subset of movers. Minorities live in more impoverished, overcrowded neighborhoods than nonminorities, even when controlling for mobility status, contract rent, and other factors. Further, most voucher holders see the lack of rental units as a major obstacle to mobility. These findings suggest that current policy is not uniformly achieving deconcentration and that real and perceived barriers to mobility exist, especially for minorities.
Suggested Citation
Victoria Basolo and Mai Thi Nguyen (2005) “Does mobility matter? The neighborhood conditions of housing voucher holders by race and ethnicity”, Housing Policy Debate, 16(3-4), pp. 297–324. Available at: 10.1080/10511482.2005.9521546. research report
Assessing the Charging-as-a-Service (CaaS) Model for EV Charging Deployment in California
Publication Date
March 1, 2025
Associated Project
Author(s)
Areas of Expertise
Abstract
Charging-as-a-Service (CaaS) is an innovative electric vehicle (EV) charging station model that allows customers access to EV chargers through a contract with a provider responsible for design, deployment, operations, and maintenance. Little is known about the motivations and experiences of stakeholders involved in CaaS operations, including providers, electric utilities, and customers. A grey literature review identified CaaS services, provider-described benefits, and utility-provided CaaS and charging services. Then, we conducted semi-structured interviews with 13 stakeholders to identify critical themes on interactions between stakeholders and the perceptions, challenges, and opportunities of the CaaS business model in addressing charging station needs in California. CaaS may have structural benefits to customer-owned chargers and could improve charger reliability, provide scalable solutions, and reduce customer fatigue with EV charging deployment. However, CaaS faces the same challenges present in the broader charging industry. The findings in this study can guide policymakers in supporting maintenance-related workforce development and streamlining and crafting EV charging infrastructure-informed subsidy programs. Additionally, stakeholders recommend municipal-led EV infrastructure planning and funding for chargers in disadvantaged communities. These interviews clarify the role of CaaS within the EV charging industry and confirm the need for engaged policymaker support to clear roadblocks, support investment, and educate customers about decision-making, which benefits all EV charging stakeholders.
Suggested Citation
Angela Yun and Matthew D. Dean (2025) Assessing the Charging-as-a-Service (CaaS) Model for EV Charging Deployment in California. Research Report. UC ITS. Available at: https://doi.org/10.7922/g2qj7fnw.Related Publications
published journal article
A Comparative Assessment of Travel Characteristics for Neo-Traditional Developments
Transportation Research Record: Journal of the Transportation Research Board
Publication Date
January 1, 1993
Author(s)
Abstract
The primary intent of this paper is to explore the claim that transportation benefits can be derived from neotraditional neighborhood design. Conventional transportation planning models are used as tools to evaluate the performance differences of two hypothetical street networks designed to replicate a neotraditional and a conventional suburban community. Relative transportation benefits are measured in terms of vehicle-miles traveled, average trip lengths, and congestion on links and at intersections. This comparison provides an assessment of how well the two networks in question deal with trips generated by the activities which they serve. All aspects of the modeled communities are held constant except for the actual configuration of the networks. The results of this evaluation indicate that equivalent levels of activity (defined by the land uses within the community) can produce greater congestion with conventional network structures and that corresponding average trip lengths are generally longer. The ultimate goal is to determine if one network type, because of the nature of its design, can result in a more efficient transportation system. The results indicate that neotraditional designs can improve system performance.
Suggested Citation
Michael G. McNally and Sherry Ryan (1993) “A Comparative Assessment of Travel Characteristics for Neo-Traditional Developments”, Transportation Research Record: Journal of the Transportation Research Board [Preprint], (1400). Available at: https://onlinepubs.trb.org/Onlinepubs/trr/1993/1400/1400-010.pdf. working paper
Land Use, Urban Design, and Non-Work Travel: Reproducing for Portland, Oregon, Empirical Tests from other Urban Areas
Publication Date
November 1, 1999