published journal article
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published journal article
Uncertainty and the timing of an urban congestion relief investment.
Journal of Urban Economics
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Author(s)
Abstract
We analyze the impact of population uncertainty on the socially optimum timing of a congestion-relief project in a linear monocentric city with fixed boundaries, where congestion pricing cannot be implemented. This project requires time to bear fruit but no urban land. Under certainty, we show that utility maximization is roughly equivalent to a standard benefit-cost analysis (BCA). Under Uncertainty, we derive an explicit optimal threshold for relieving congestion when the urban population follows a geometric Brownian motion. If the time to implement the project is short, we show analytically that deciding on the timing of congestion relief based on a BCA could lead to acting prematurely; the reverse holds if project implementation is long and uncertainty is large enough. (c) 2005 Elsevier Inc. All rights reserved.
Suggested Citation
Jean-Daniel M. Saphores and Marlon G. Boarnet (2006) “Uncertainty and the timing of an urban congestion relief investment.”, Journal of Urban Economics, 59(2), pp. 189–208. Available at: 10.1016/j.jue.2005.04.003.published journal article
Short-term traffic flow prediction using neuro-genetic algorithms
Journal of Intelligent Transportation Systems
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Author(s)
Suggested Citation
Baher Abdulhai, Himanshu Porwal and Will Recker (2002) “Short-term traffic flow prediction using neuro-genetic algorithms”, Journal of Intelligent Transportation Systems, 7(1), pp. 3–41. Available at: 10.1080/713930748.research report
Fine Particulate Concentrations Near Arterial Streets: The Influence of Building Placement and Wind Flow
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Associated Project
Author(s)
Abstract
This paper provides preliminary evidence that the placement of buildings influences the concentration of fine particulates by altering wind flow. The authors collected measurements of fine particulate concentration, wind speed, wind direction, and traffic levels around five Southern California arterials selected to represent a range of building densities. In some cases the difference in average concentrations between opposite sides of the street was on the order of 10 μg/m3. In most cases the concentration was higher on the upwind side of the street, where the wind wakes of buildings limit the dispersion of particulates. Although this work is exploratory in nature, it reveals that fine particulate concentrations can vary even within a single city block, a scale finer than those used in current policy models. Given the trend towards infill development and densification in many places, this is an important topic that warrants further research to more fully understand the influence of the built environment on air quality.
Suggested Citation
Marlon Boarnet, GAVIN FERGUSON and RUFUS D EDWARDS (2010) Fine Particulate Concentrations Near Arterial Streets: The Influence of Building Placement and Wind Flow. Research Report. ITS-Irvine. Available at: https://escholarship.org/uc/item/3jk569f1.book/book chapter
Using the price system to reduce airport congestion
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Author(s)
Suggested Citation
J.K. Brueckner (2012) “Using the price system to reduce airport congestion”, in Issues of the day: 100 commentaries on climate, energy, the environment, transportation, and public health policy, pp. 162–163.conference paper
Revisiting Physical-World Adversarial Attack on Traffic Sign Recognition: A Commercial Systems Perspective
ISOC Network and Distributed System Security Symposium (NDSS) 2025
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Author(s)
Abstract
Traffic Sign Recognition (TSR) is crucial for safe and correct driving automation. Recent works revealed a general vulnerability of TSR models to physical-world adversarial attacks, which can be low-cost, highly deployable, and capable of causing severe attack effects such as hiding a critical traffic sign or spoofing a fake one. However, so far existing works generally only considered evaluating the attack effects on academic TSR models, leaving the impacts of such attacks on real-world commercial TSR systems largely unclear. In this paper, we conduct the first large-scale measurement of physical-world adversarial attacks against commercial TSR systems. Our testing results reveal that it is possible for existing attack works from academia to have highly reliable (100%) attack success against certain commercial TSR system functionality, but such attack capabilities are not generalizable, leading to much lower-than-expected attack success rates overall. We find that one potential major factor is a spatial memorization design that commonly exists in today’s commercial TSR systems. We design new attack success metrics that can mathematically model the impacts of such design on the TSR system-level attack success, and use them to revisit existing attacks. Through these efforts, we uncover 7 novel observations, some of which directly challenge the observations or claims in prior works due to the introduction of the new metrics.
Suggested Citation
Ningfei Wang, Shaoyuan Xie, Takami Sato, Yunpeng Luo, Kaidi Xu and Qi Alfred Chen (2025) “Revisiting Physical-World Adversarial Attack on Traffic Sign Recognition: A Commercial Systems Perspective”, in ISOC Network and Distributed System Security Symposium (NDSS) 2025. Available at: https://ics.uci.edu/~alfchen/pubs/ningfei_ndss25.pdf.research report
Exploratory use of raster images as a data source for agricultural commodity transportation modeling
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Author(s)
Suggested Citation
Pedro V Camargo, Michael G McNally and Stephen G Ritchie (2014) Exploratory use of raster images as a data source for agricultural commodity transportation modeling.published journal article
Real-time inductive-signature-based level of service for signalized intersections
Transportation Research Record
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Author(s)
Suggested Citation
Cheol Oh and Stephen G. Ritchie (2002) “Real-time inductive-signature-based level of service for signalized intersections”, Transportation Research Record, 1802(1), pp. 97–104. Available at: 10.3141/1802-12.published journal article
A Link Queue Model of Network Traffic Flow
Transportation Science
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Author(s)
Abstract
Fundamental to many transportation network studies, traffic flow models can be used to describe traffic dynamics determined by drivers’ car-following, lane-changing, merging, and diverging behaviors. In this study, we develop a deterministic queueing model of network traffic flow, in which traffic on each link is considered as a queue. In the link queue model (LQM), the demand and supply of a link queue are defined in the queue size (number of vehicles), and its in- and out-flows are computed from junction flux functions corresponding to macroscopic merging and diverging rules. The new model is a system of ordinary differential equations that is mathematically tractable and computationally efficient and can capture queue spillbacks and interactions among links. We further demonstrate that the LQM is fundamentally different from the cell transmission model (CTM) and link transmission model (LTM) for a road segment, a signalized ring road, and a diverge-merge network, with respect to the shock and rarefaction waves, network fundamental diagram, and stability property. In a sense, the new model is a space-continuous approximation of the kinematic wave model and can be a useful addition to the multiscale modeling framework of network traffic flow. The model has been applied to formulate and solve network traffic control and observation problems.
Suggested Citation
Wen-Long Jin (2021) “A Link Queue Model of Network Traffic Flow”, Transportation Science, 55(2), pp. 436–455. Available at: 10.1287/trsc.2020.1012.conference paper