conference paper
Towards Driving-Oriented Metric for Lane Detection Models
Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition
Publication Date
January 1, 2022
Archives: Research Products
working paper
Part-Time Operators in Public Transit: Experiences and Prospects
Publication Date
April 1, 1985
Author(s)
Working Paper
UCI-ITS-WP-85-3
Areas of Expertise
Abstract
Most U.S. transit agencies have begun to use part-time operators as a means to reduce operating cost. This report, based on five case studies, evaluates the cost savings and organizational impacts associated with this change. Results indicate that cost savings have been small but significant in situations where peak service expansion occurred. But where the schedule was static, contract protections for existing operators have made it difficult to use part-time labor, and hence savings were small or insignificant. We find that in transit agencies with highly peaked schedules, part-time operators (PTOs) save money for two reasons: they improve schedule efficiency (the ratio of hours-paid to hours-worked), and their wages and fringe benefits are lower than those of full time operators. In agencies with relatively flat schedules the only savings is from lower wages and fringes, and it is possible that this kind of “two-tier” wage system may be bargained away over time. We find that for agencies with flat or static schedules, it may be more effective to concentrate on alternative strategies such as absenteeism control and extraboard staffing which may be more beneficial and easier to implement. On the organizational side, we find no unusual costs associated with use of PTOs. They have proven to be as reliable, or even more so, than full time operators; they have not created unusual supervisory costs, and there have been relatively few problems between part-time and full-time operators. We also find that instead of creating a permanent force of PTOs, as had been anticipated, most of the PTOs that were hired really wanted full-time work.
Suggested Citation
Kenneth M. Chomitz, Genevieve Giuliano and Charles A. Lave (1985) Part-Time Operators in Public Transit: Experiences and Prospects. Working Paper UCI-ITS-WP-85-3. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/1jm5106j.
published journal article
The impact of plug-in vehicles on greenhouse gas and criteria pollutants emissions in an urban air shed using a spatially and temporally resolved dispatch model
Journal of Power Sources
Publication Date
December 1, 2011
Author(s)
Suggested Citation
Ghazal Razeghi, Tim Brown and G. Scott Samuelsen (2011) “The impact of plug-in vehicles on greenhouse gas and criteria pollutants emissions in an urban air shed using a spatially and temporally resolved dispatch model”, Journal of Power Sources, 196(23), pp. 10387–10394. Available at: 10.1016/j.jpowsour.2011.08.043. published journal article
Business Churning and Neighborhood Instability: Is There a Link?
International Regional Science Review
Publication Date
January 12, 2023
Author(s)
Jae Hong Kim, Kevin Kane, Young-An Kim, John R. Hipp
Abstract
Much of the work concerning economic dynamism has focused on its aggregate-level implications, while there have been rising concerns about business displacement at the community or neighborhood level. In this article, we analyze this important (restructuring) process using detailed establishment-level business information and explore how it manifests itself across space within the Los Angeles—Long Beach—Santa Ana, CA Urbanized Area. We also investigate the association between business churning and neighborhood-level housing vacancy rates to understand the implications of dramatic changes in the business landscape. We find that housing vacancies are more likely to increase in urban neighborhoods with a higher establishment death rate, while the creation of new businesses can mitigate the association to some extent. We also detect substantial variation across decades not only in the spatial distribution of business churning but also in its association with housing vacancy rates, suggesting the evolving nature of business dynamics and their implications.
Suggested Citation
Jae Hong Kim, Kevin Kane, Young-An Kim and John R. Hipp (2023) “Business Churning and Neighborhood Instability: Is There a Link?”, International Regional Science Review, p. 01600176221145873. Available at: 10.1177/01600176221145873. research report
Exploring Transportation Mode Choice and Participation in LA Metro’s “GoPass” Program Among Los Angeles Community College Students
Publication Date
July 2, 2026
Author(s)
Abstract
This research evaluates LA Metro’s GoPass program—a fare-free transit initiative for K-12 and community college students—through a survey of Los Angeles Community College District (LACCD) students. The research team investigated students’ travel preferences through a discrete choice experiment, assessed GoPass awareness and participation impacts on transit use, and analyzed spatial and seasonal ridership patterns from TAP card records. GoPass participation increased transit use by 26 percentage points for school trips and 19 percentage points for discretionary trips, with greater benefits for socioeconomically disadvantaged students. Even students aware of GoPass but not participating showed a 5.8 percentage point increase in school related transit use. However, 39% of eligible students were unaware of the program, and car access reduced transit use probability by 37 percentage points. The discrete choice experiment revealed students valued travel time savings at $27–$54 per hour and Wi-Fi availability at $6–$7 per trip. Modest travel time reductions generated larger welfare gains than free fares alone, suggesting service improvements may offer better returns than fare subsidies. Analysis of 1.1 million TAP card records showed substantial seasonal variation: summer ridership declined 37.5% for buses and 32.2% for rail. Single-vehicle households maintained more consistent usage (+11.9%), while three-vehicle households showed the largest declines (-40.9%). Areas with high transit stop density and high violent crime maintained more consistent usage, reflecting transit-dependent populations. These findings demonstrate that increasing student transit ridership requires addressing service quality, coverage, and program awareness beyond fare reductions alone.
published journal article
Travel Probability Fields and Urban Spatial Structure: 1. Theory
Environment and Planning A: Economy and Space
Publication Date
May 1, 1983
Author(s)
M J Beckmann, Thomas Golob, Y Zahavi
Abstract
The proposed model attempts to explain how particular spatial distributions of trip destinations might arise as manifestations of the accessibility benefits and travel costs associated with a housing location. The trip distributions are elliptical, being expressed as bivariate normal distributions. The parameters of these distributions are shown to be related to the parameters of an assumed density function for activity sites (such as jobs and shops) and to travel speeds. The model implies a housing density function in a monocentric urban area which is negative exponential.
Suggested Citation
M J Beckmann, T F Golob and Y Zahavi (1983) “Travel Probability Fields and Urban Spatial Structure: 1. Theory”, Environment and Planning A: Economy and Space, 15(5), pp. 593–606. Available at: 10.1068/a150593. published journal article
The association between ambient air pollutants and pancreatic cancer in the Multiethnic Cohort Study
Environmental Research
Publication Date
November 1, 2021
Author(s)
David Bogumil, Anna H. Wu, Daniel Stram, Johnny Yang, Chiu-Chen Tseng, Loïc Le Marchand, Jun Wu, Iona Cheng, Veronica Wendy Setiawan
Abstract
Background Prior studies examining the association between ambient air pollutants and pancreatic cancer have been conducted in racially/ethnically homogeneous samples and have produced mixed results, with some studies supporting evidence of an association with fine particulate matter. Methods To further investigate these findings, we estimated exposure levels of particulate matter (PM2.5, PM10) and oxides of nitrogen (NOX, and NO2) using kriging interpolation for 100,527 men and women from the Multiethnic Cohort Study, residing largely in Los Angeles County from 1993 through 2013. We measured the association between these air pollutants and incident pancreatic cancer using Cox proportional hazards models with time-varying pollutant measures, with adjustment for confounding factors. Results A total of 821 incident pancreatic cancer and 1,660,488 person-years accumulated over the study period, with an average follow-up time of over 16 years. PM2.5 (per 10 μg/m3) was associated with incident pancreatic cancer (hazard ratio [HR] = 1.61; 95% CI, 1.09, 2.37). This PM2.5 -association was strongest among Latinos (HR = 3.59; 95% CI, 1.60, 8.06) and ever smokers (HR = 1.76; 95% CI, 1.05, 2.94). There was no association for PM10 (HR = 1.12; 95% CI, 0.94, 1.32, per 10 μg/m3), NOx (HR = 1.14; 95% CI, 0.88, 1.48, per 50 ppb), or NO2 (HR = 1.14; 95% CI, 0.85, 1.54, per 20 ppb). Conclusions Our findings support prior research identifying an association between fine particulate matter, PM2.5, and pancreatic cancer. Although not statistically heterogeneous, this association was most notable among Latinos and smokers. Future studies are needed to replicate these results in an urban setting and in a racially/ethnically diverse population.
Suggested Citation
David Bogumil, Anna H. Wu, Daniel Stram, Juan Yang, Chiu-Chen Tseng, Loïc Le Marchand, Jun Wu, Iona Cheng and Veronica Wendy Setiawan (2021) “The association between ambient air pollutants and pancreatic cancer in the Multiethnic Cohort Study”, Environmental Research, 202, p. 111608. Available at: 10.1016/j.envres.2021.111608. published journal article
Thinking styles affect reactions to brand crisis apologies
European Journal of Marketing
Publication Date
July 1, 2016
Author(s)
Suggested Citation
Liangyan Wang, Shijian Wang, L. Robin Keller and Jie Li (2016) “Thinking styles affect reactions to brand crisis apologies”, European Journal of Marketing, 50(7/8), pp. 1263–1289. Available at: 10.1108/ejm-07-2014-0457. conference paper
On the realism of lidar spoofing attacks against autonomous driving vehicle at high speed and long distance
Proceedings of the Network and Distributed System Security Symposium (NDSS)x
Publication Date
January 1, 2025
Author(s)
Takami Sato, Ryo Suzuki, Yuki Hayakawa, Kazuma Ikeda, Ozora Sako, Rokuto Nagata, Ryo Yoshida, Qi Alfred Chen, Kentaro Yoshioka
Areas of Expertise
Suggested Citation
Takami Sato, Ryo Suzuki, Yuki Hayakawa, Kazuma Ikeda, Ozora Sako, Rokuto Nagata, Ryo Yoshida, Qi Alfred Chen and Kentaro Yoshioka (2025) “On the realism of lidar spoofing attacks against autonomous driving vehicle at high speed and long distance”, in Proceedings of the Network and Distributed System Security Symposium (NDSS)x. Available at: https://www-test.ics.uci.edu/~alfchen/pubs/takami_ndss25.pdf (Accessed: August 21, 2025). book/book chapter
Urban Decline and the Future of American Cities:
Publication Date
January 1, 2011
Author(s)
Katharine L Bradbury, Anthony Downs, Kenneth Small
Abstract
During the past two decades, most large American cities have lost population, yet some have continued to grow. Does this trend foreshadow the death” of our largest cities? Or is urban decline a temporary phenomenon likely to be reversed by high energy costs? This ambitious book tackles these questions by analyzing the nature and extent of urban decline and growth of large U.S. cities. It includes and integrates five substudies. The first examines urban decline and some of its long-run causes, and whether cities that are losing population are performing their economic and social functions less effectively. The second substudy is a multivariate analysis of factors associated with the growth and decline of 121 large U.S. cities and their metropolitan areas. Although its causes vary, urban decline appears closely related to processes that have both upgraded individual households and generated serious problems for city governments and poor neighborhoods. A third substudy shows that neighborhood decline is part of a systematic process related to the influx of poor households into metropolitan areas. Another substudy simulates five antidecline strategies in a single metropolitan area, that of Cleveland, Ohio, and finds that severe decline (occurring in about one-fourth of large U.S. cities) could be slowed, though not stopped by vigorous policies. From the last substudy it emerges that, even if gasoline prices rose to over $2 a gallon, resulting adjustments by commuters and firms would produce little net centralization of future urban developmentthough many older neighborhoods would probably be rehabilitated. The book concludes that further losses of population and jobs in most severely declining cities are unavoidable in the near future. Even Southern and Western cities, now growing fast, will find their rate of growth slowing as further annexation of surrounding territory is limited. The book ends with two chapters discussing policies designed both to help declining population and job losses and to minimize such loses in other cities.