conference paper

Exposing congestion attack on emerging connected vehicle based traffic signal control

Proceedings 2018 network and distributed system security symposium

Publication Date

January 1, 2018

Author(s)

Qi Alfred Chen, Yafeng Yin, Yiheng Feng, Z. Morley Mao, Henry Liu

Abstract

Connected vehicle (CV) technology is taking tremendous strides toward increased transportation mobility efficiency by connecting vehicles with transportation infrastructure via wireless communications. However, cybersecurity threats are rising in tandem with the increasing sophistication of CV technology. This study performs a security analysis of the U.S. Department of Transportation CV-based traffic control system. In particular, it analyzes the threat of traffic congestion resulting from CV data spoofing by an attack vehicle. The first step was to identify and evaluate possible data spoofing strategies and their effectiveness. Then the causes of the most effective strategies were investigated. The current signal control algorithm was found to be deeply vulnerable to data spoofing attacks, with traffic congestion increasing by 23.4% compared to traffic without CV-based signal control. Other attacks can cause jamming to such an extent that vehicles are required to take 7 minutes for a trip that should only take a half-minute, a fourteen-fold increase. In order to defend against these cybersecurity threats, three suggestions are given. First, more robust algorithms are needed during the transition period to 95% market penetration, which may take as long as thirty years. Second, performance enhancement in road-side units is needed in order to provide improved traffic control configurations. Third, upgraded data spoofing detection using infrastructure-controlled sensors is recommended.

Suggested Citation
Qi Alfred Chen, Yucheng Yin, Yiheng Feng, Z. Morley Mao and Henry X. Liu (2018) “Exposing congestion attack on emerging connected vehicle based traffic signal control”, in Proceedings 2018 network and distributed system security symposium. Internet Society, p. 15p. Available at: 10.14722/ndss.2018.23222.

published journal article

Why do they live so far from work? Determinants of long-distance commuting in California

Journal of Transport Geography

Publication Date

October 1, 2019

Abstract

The determinants of long-distance commuting (trips longer than 50â?¯miles one-way) in the U.S. appear to be poorly understood even though long-distance commuting likely has substantial environmental, social, and economic impacts. A review of the literature shows that that few papers have considered how housing costs influence long-distance commuting. Moreover, residential self-selection has rarely been accounted for in commuting studies. To start addressing these gaps, the authors analyze the long-distance travel component of the 2012 California Household Travel Survey via a generalized structural equation model. In their model, land use and housing costs are explained by household and head of household characteristics; together with these characteristics, land use and housing costs influence long-distance commuting. The authors find that the probability of a household commuting long-distance decreases with an increase in the job-housing ratio (ORâ?¯=â?¯0.914***) and most importantly, with the median home value of the census tract where a household resides (ORâ?¯=â?¯0.488***). Conversely, this probability increases with the median census tract home values where household members work (ORâ?¯=â?¯1.765***). Finally, the authors’ model results confirm the presence of small residential self-selection effects. These results highlight the importance of providing more affordable housing and mixed development options to reduce long-distance commuting and its associated environmental impacts.

Suggested Citation
Suman K. Mitra and Jean-Daniel M. Saphores (2019) “Why do they live so far from work? Determinants of long-distance commuting in California”, Journal of Transport Geography, 80, p. 102489. Available at: 10.1016/j.jtrangeo.2019.102489.

conference paper

Study of a Dynamic Cooperative Trading Queue Routing Control Scheme for Freeways and Facilities with Parallel Queues

Proceedings of the 97th annual meeting of the transportation research board

Publication Date

January 1, 2018

Abstract

This article explores the coalitional stability of a new cooperative control policy for freeways and parallel queuing facilities with multiple servers. Based on predicted future delays per queue or lane, a VOT-heterogeneous population of agents can agree to switch lanes or queues and transfer payments to each other in order to minimize the total cost of the incoming platoon. The strategic interaction is captured by an n-level Stackelberg model with coalitions, while the cooperative structure is formulated as a partition function game (PFG). The stability concept explored is the strong-core for PFGs which we found appropiate given the nature of the problem. This concept ensures that the efficient allocation is individually rational and coalitionally stable. We analyze this control mechanism for two settings: a static vertical queue and a dynamic horizontal queue. For the former, we first characterize the properties of the underlying cooperative game. Our simulation results suggest that the setting is always strong-core stable. For the latter, we propose a new relaxation program for the strong-core concept. Our simulation results on a freeway bottleneck with constant outflow using Newell’s car-following model show the imputations to be generally strong-core stable and the coalitional instabilities to remain small with regard to users’ costs.

Suggested Citation
Roger Lloret-Batlle and R. Jayakrishnan (2018) “Study of a Dynamic Cooperative Trading Queue Routing Control Scheme for Freeways and Facilities with Parallel Queues”, in Proceedings of the 97th annual meeting of the transportation research board. arXiv, p. 6p. Available at: 10.48550/ARXIV.1803.01265.

published journal article

Association between Airport Ultrafine Particles and Lung Cancer Risk: The Multiethnic Cohort Study

Cancer Epidemiology, Biomarkers & Prevention

Publication Date

May 1, 2024

Author(s)

Arthur Bookstein, Justine Po, Chiuchen Tseng, Timothy V. Larson, Juan Yang, Sung-shim L. Park, Jun Wu, Salma Shariff-Marco, Pushkar P. Inamdar, Ugonna Ihenacho, Veronica W. Setiawan, Mindy C. DeRouen, Loïc Le Marchand, Daniel O. Stram, Jonathan Samet, Beate Ritz, Scott Fruin, Anna H. Wu, Iona Cheng

Abstract

Ultrafine particles (UFP) are unregulated air pollutants abundant in aviation exhaust. Emerging evidence suggests that UFPs may impact lung health due to their high surface area-to-mass ratio and deep penetration into airways. This study aimed to assess long-term exposure to airport-related UFPs and lung cancer incidence in a multiethnic population in Los Angeles County.Within the California Multiethnic Cohort, we examined the association between long-term exposure to airport-related UFPs and lung cancer incidence. Multivariable Cox proportional hazards regression models were used to estimate the effect of UFP exposure on lung cancer incidence. Subgroup analyses by demographics, histology and smoking status were conducted.Airport-related UFP exposure was not associated with lung cancer risk [per one IGR HR, 1.01; 95% confidence interval (CI), 0.97–1.05] overall and across race/ethnicity. A suggestive positive association was observed between a one IQR increase in UFP exposure and lung squamous cell carcinoma (SCC) risk (HR, 1.08; 95% CI, 1.00–1.17) with a Phet for histology = 0.05. Positive associations were observed in 5-year lag analysis for SCC (HR, 1.12; 95% CI, CI, 1.02–1.22) and large cell carcinoma risk (HR, 1.23; 95% CI, 1.01–1.49) with a Phet for histology = 0.01.This large prospective cohort analysis suggests a potential association between airport-related UFP exposure and specific lung histologies. The findings align with research indicating that UFPs found in aviation exhaust may induce inflammatory and oxidative injury leading to SCC.These results highlight the potential role of airport-related UFP exposure in the development of lung SCC.

Suggested Citation
Arthur Bookstein, Justine Po, Chiuchen Tseng, Timothy V. Larson, Juan Yang, Sung-shim L. Park, Jun Wu, Salma Shariff-Marco, Pushkar P. Inamdar, Ugonna Ihenacho, Veronica W. Setiawan, Mindy C. DeRouen, Loïc Le Marchand, Daniel O. Stram, Jonathan Samet, Beate Ritz, Scott Fruin, Anna H. Wu and Iona Cheng (2024) “Association between Airport Ultrafine Particles and Lung Cancer Risk: The Multiethnic Cohort Study”, Cancer Epidemiology, Biomarkers & Prevention, 33(5), pp. 703–711. Available at: 10.1158/1055-9965.EPI-23-0924.

published journal article

Subprime mortgages and the housing bubble

Journal of Urban Economics

Publication Date

March 1, 2012

Author(s)

Jan Brueckner, Paul S. Calem, Leonard I. Nakamura

Abstract

This paper explores the link between the house-price expectations of mortgage lenders and the extent of subprime lending. It argues that bubble conditions in the housing market are likely to spur subprime lending, with favorable price expectations easing the default concerns of lenders and thus increasing their willingness to extend loans to risky borrowers. Since the demand created by subprime lending feeds back onto house prices, such lending also helps to fuel an emerging housing bubble. These ideas are illustrated in a theoretical model, and tentative support is found in empirical work exploring the connection between price expectations and the extent of subprime lending. (C) 2011 Elsevier Inc. All rights reserved.

Suggested Citation
Jan K. Brueckner, Paul S. Calem and Leonard I. Nakamura (2012) “Subprime mortgages and the housing bubble”, Journal of Urban Economics, 71(2), pp. 230–243. Available at: 10.1016/j.jue.2011.09.002.

working paper

The Location Selection Problem for the Household Activity Pattern Problem

Publication Date

September 5, 2012

Working Paper

UCI-ITS-WP-12-1

Areas of Expertise

Abstract

In this paper, an integrated destination choice model based on routing and scheduling considerations of daily activities is proposed. Extending the Household Activity Pattern Problem (HAPP), the Location Selection Problem (LSP-HAPP) demonstrates how location choice is made as a simultaneous decision from interactions both with activities having predetermined locations and those with many candidate locations. A dynamic programming algorithm, developed for PDPTW, is adapted to handle a potentially sizable number of candidate locations. It is shown to be efficient for HAPP and LSP-HAPP applications. The algorithm is extended to keep arrival times as functions for mathematical programming formulations of activity-based travel models that often have time variables in the objective.

Suggested Citation
Jee Eun Kang and Will W. Recker (2012) The Location Selection Problem for the Household Activity Pattern Problem. Working Paper UCI-ITS-WP-12-1. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/5865d8xf.

working paper

Johnny Walks to School - Does Jane? Sex Differences in Children's Active Travel to School

Abstract

Communities are traditionally built with one transportation mode and user in mind—the adult automobile driver. Recently, however, there has been an international focus on the trip to school as an opportunity to enhance children’s independent active travel. Several factors must be considered when designing programs to promote walking and bicycling. This paper examined the influence of child sex on caregivers’ decisions about travel mode choice to school.

Caregivers of children in grades three to five from ten California Safe Routes to School communities were surveyed on their child’s normal travel mode to school and factors that determined travel decisions. Results indicate that the odds of walking and bicycling to school are 40 percent lower in girls than boys; however, this relationship is significantly moderated by the caregiver’s own walking behavior. The findings suggest that programs that focus on increasing children’s active travel to school should consider multiple influences on health behavior, including the neighborhood physical activity of parents.

Phd Dissertation

Modeling individual route choice with automated real -time vehicle trip histories

Abstract

Collecting rich individual trip data at an individual level has long been viewed as a hard task and has become a bottleneck in modeling and calibrating travel behavior models since traditional survey methods are both costly and time-consuming. New technologies make such data a possibility and thus there is a need for frameworks that model individual behavior in real-time using such data. Such modeling will find use in a variety of real-time network optimization and prediction schemes. This dissertation describes the details of plausible behavioral modeling of this kind, and develops new data structures that are needed both for handling the network combinatorics in the analysis and in the data storage. The work is presented in the context of a new technology we propose called the Persistent Traffic Cookie (PTC) system which uses the short range wireless connection between vehicles and road side controllers to store authenticated, time-stamped node sequences on an onboard database. The dissertation makes the premise that traditional travel behavior models, including those based on disaggregate decision paradigms were developed primarily for application in aggregate level prediction and are thus not very applicable for an individual’s route choice prediction in real-time. A scheme that does not require variation of explanatory variables across the choice sets or variation in the individual’s decisions for calibration may be essential. Thus the dissertation developed models based on observed frequencies of decisions. The research also stresses the importance of path and sub-path notions in route choice decisions and provides appropriate data structures that enable modeling with such notions. Two methods that directly query the collected sequence data using efficient data structures based on the suffix tree and the suffix array schemes and node/edge transition probability model, are proposed to predict individual travels from trip diary database. A day-to-day PTC simulation framework with behavior components is proposed to generate consistent PTC data and implemented in Paramics microscopic traffic simulator. Day-to-day PTC simulations are carried out for two Paramics networks, including the Irvine Triangle network, which is a well-calibrated real world network. Various scenarios are created to test the sensitivities of the proposed prediction methods. The simulation results shows that it seems the prediction methods are robust with regard to the underlying behavior models, traffic conditions and tracking periods.

Suggested Citation
Yu Zhang (2006) Modeling individual route choice with automated real -time vehicle trip histories. Ph.D.. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/1gpb62p/alma991035092986404701 (Accessed: October 14, 2023).

working paper

Formal Structure as a Constraint on Interaction within Organizations

Abstract

In contrast to existing theories of organizations that stress the vertical control of intraorganizational interaction, a structural perspective is discussed that emphasizes the networks of social interaction that develop horizontally and diagonally, as well as vertically, across the organization. As an example of this perspective, the effects of the hierarchical arrangement of positions, both in terms of the unequal number of individuals in vertical levels and in terms of the differential allocation of resources across vertical levels, is hypothesized to lead to differential rates of interaction across the organization. These effects of structural differentiation on networks of interaction are tested in a public bureaucracy, and the implications of differentiation for the formation of networks of interaction and resulting collective actions such as coalition formation are discussed.

Suggested Citation
William B. Stevenson (1986) Formal Structure as a Constraint on Interaction within Organizations. Working Paper UCI-ITS-WP-86-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/5s87s550.

MS Thesis

Microscopic simulation and emissions study of the electrification of the I-710 freight corridor

Publication Date

January 1, 2014

Author(s)

Abstract

Due to heavy congestion and air pollutants emissions from the increase in container trucks traveling on the I-710, Caltrans and Metro have been looking into viable alternatives for solving these problems. The heavy health burden on residents of the areas surrounding the I-710 has been a cause for concern to these agencies for some time. In this study, I rely on microscopic traffic simulation and on operating modes (OpModes) lookup tables from MOVES to estimate changes in congestion and in emissions of various air pollutants (including nitrogen oxides (NOx) and particulate matter (PM)) resulting from the creation of electrified truck lanes on I-710. This alternative was tested for four scenarios corresponding to different percentage of electrified heavy-duty trucks in the I-710 corridor. My results show that creating electrified lanes would slightly reduce congestion in terms of average overall network speed. I also found a substantial reduction in the emissions of several air pollutants by port-related heavy duty trucks, which ranged from 44% to 94% in the scenarios considered. Overall, the reduction in emission possible by the electrification of the freight corridor is a significant improvement but as proposed, the electrification of the I-710 would also create additional traffic problems. This suggests that planning models (such as TransCad) are not sufficient to properly evaluate preliminary designs of freeway changes.

Suggested Citation
Sarah Tasnim (2014) Microscopic simulation and emissions study of the electrification of the I-710 freight corridor. MS Thesis. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991015107149704701.