working paper

Death on the Crosswalk: A Study of Pedestrian-Automobile Collisions in Los Angeles

Publication Date

April 1, 2005

Author(s)

Anastasia Loukaitou-Sideris

Abstract

This research explores the spatial distribution of pedestrian-automobile collisions in Los Angeles and analyzes the social and physical factors that affect the risk of getting involved in such accidents. More specifically, this study investigates the influence of socio-demographic, land use, density, and traffic characteristics on pedestrian accident rates.

We first provide an exploratory spatial and statistical analysis of pedestrian collision data in the city of Los Angeles to identify preliminary relationships between accident frequency and socio-demographic and land use characteristics at the census tract and block group levels. This aggregate level analysis also helps us identify major concentrations of pedestrian collision data which are used at a second stage of the research for more qualitative and detailed analysis of specific case studies of intersections with high frequency of pedestrian-automobile accidents. The study uses pedestrian accident data provided by the Los Angeles Department of Transportation, traffic volume data provided by Caltrans, socio-demographic data from the U.S. Census 2000, land use data from the Southern California Association of Governments (SCAG), and pedestrian volume and built environment data from fieldwork research.

published journal article

Norm approximation method for handling traffic count inconsistencies in path flow estimator

Transportation Research Part B: Methodological

Publication Date

September 1, 2009

Author(s)

Anthony Chen, Piya Chootinan, Will Recker
Suggested Citation
Anthony Chen, Piya Chootinan and Will Recker (2009) “Norm approximation method for handling traffic count inconsistencies in path flow estimator”, Transportation Research Part B: Methodological, 43(8-9), pp. 852–872. Available at: 10.1016/j.trb.2009.02.007.

conference paper

Event-based communication strategy for collaborative navigation with signals of opportunity

2018 52nd asilomar conference on signals, systems, and computers

Publication Date

October 1, 2018

Author(s)

Joshua Morales, Zaher Kassas
Suggested Citation
Joshua Morales and Zaher M. Kassas (2018) “Event-based communication strategy for collaborative navigation with signals of opportunity”, in 2018 52nd asilomar conference on signals, systems, and computers. IEEE, pp. 548–553. Available at: 10.1109/acssc.2018.8645193.

Preprint Journal Article

Revisiting Physical-World Adversarial Attack on Traffic Sign Recognition: A Commercial Systems Perspective

Publication Date

September 15, 2024

Author(s)

Ningfei Wang, Shaoyuan Xie, Takami Sato, Yunpeng Luo, Kaidi Xu, Qi Alfred Chen

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 (2024) “Revisiting Physical-World Adversarial Attack on Traffic Sign Recognition: A Commercial Systems Perspective”. arXiv. Available at: 10.14722/ndss.2025.23090.

working paper

Autos, Transit and the Sprawl of Los Angeles: The 1920s

Publication Date

March 1, 1984

Author(s)

Martin Wachs

Working Paper

UCI-ITS-WP-84-2

Abstract

The dispersed, low-density land-use pattern that has come to be associated with Los Angeles has roots in two periods of economic growth during which critical choices were made. While many observers associate the sprawl of Los Angeles with the freeway building program following World War II, the pattern was quite well established prior to 1930. It can be traced to an early period of dispersed growth, from 1880 to 1910, when inter-urban street railways allowed residential decentralization. The pattern was reinforced during the boom of the nineteen twenties, when rapid growth was accompanied by dramatic shifts in travel patterns and industrial location, partly in response to the automobile. This paper examines changes during these periods in the context of a continuing preference for low density living, and reviews the planning policies and political decisions of the twenties, when a comprehensive highway program was adopted, but a regional rapid transit plan failed to gain acceptance.

Suggested Citation
Martin Wachs (1984) Autos, Transit and the Sprawl of Los Angeles: The 1920s. Working Paper UCI-ITS-WP-84-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/7wq9b14d.

published journal article

California households' willingness to pay for `green' electronics

Journal of Environmental Planning and Management

Publication Date

January 1, 2007

Author(s)

Abstract

Concerns about rapid increases in the volume of electronic waste (e-waste) and its potential toxicity have sharpened policy makers’ interest for extended producer responsibility to encourage manufacturers of consumer electronic devices (CEDs) to `design for the environment’. This paper examines consumer willingness to pay for `green’ electronics based on a 2004 mail survey of California households. Using ordered logit models, it was found that significant predictors of willingness to pay for `greener’ computers and cell phones include age, income, education, beliefs about the role of government for improving environmental quality, as well as environmental attitudes and behaviors, but neither gender nor political affiliation. Although most respondents are willing to pay only a 1% premium for `greener’ CEDs, innovation and EU directives may soon make them competitive with conventional CEDs.

Suggested Citation
Jean-Daniel M. Saphores, Hilary Nixon, Oladele A. Ogunseitan and Andrew A. Shapiro (2007) “California households' willingness to pay for `green' electronics”, Journal of Environmental Planning and Management, 50(1), pp. 113–133. Available at: 10.1080/09640560601048549.

working paper

Toward a Dynamic Model of Individual Activity Pattern Formulation

Publication Date

July 1, 1981

Working Paper

UCI-ITS-WP-81-4, UCI-ITS-AS-WP-81-2

Areas of Expertise

Abstract

This paper presents preliminary thoughts on the development of a theoretical model of complex travel/activity behavior that incorporates both spatial and temporal constraints. The theoretical model is based on the use of individual activity patterns to represent complex travel/ activity behavior and assumes the form of a stochastic multiobjective dynamic programming model. A multiobjective dynamic programming approach is utilized due to the presence of conflicting objectives and the influence that past activity/travel decisions have on future choices. 

Suggested Citation
Gregory S. Root and Will Recker (1981) Toward a Dynamic Model of Individual Activity Pattern Formulation. Working Paper UCI-ITS-WP-81-4, UCI-ITS-AS-WP-81-2. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/7t72q459.

working paper

On the Structure of Weekly Activity/Travel Patterns

Publication Date

September 1, 2003

Working Paper

UCI-ITS-WP-01-8, UCI-ITS-AS-WP-01-3

Areas of Expertise

Abstract

Understanding the process of activity scheduling is a critical prerequisite to an understanding changes in travel behavior. To examine this process, a web-based activity survey program, REACT!, was developed to collect household activity scheduling data. REACT! is unique in that it records the evolution of activity schedules from intentions to final outcomes for a multi-day period. This paper summarizes an investigation of the structure of activity/travel patterns based on a REACT! data set from a pilot study conducted in Irvine, California. The term structure refers to the outcome of a set of decisions facing individuals as they conduct their daily activities. At a minimum, structure can be interpreted as the sequence by which various activities enter one’s daily activity scheduling process. Results of the empirical analyses show that activities of shorter duration were more likely to be opportunistically inserted in a schedule already anchored by longer duration counterparts. Additionally, analysis of tour structure reveals that many trip-chains were formed opportunistically. Travel time required to reach an activity was also positively related to the scheduling horizon for the activity, with more distant stops being planned earlier than closer locations.

Suggested Citation
Ming S. Lee and Michael G. McNally (2003) On the Structure of Weekly Activity/Travel Patterns. Working Paper UCI-ITS-WP-01-8, UCI-ITS-AS-WP-01-3. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/15w464vp.

conference paper

Simulated field test of open architecture transportation controller software

Pacific rim TransTech conference. 1995 vehicle navigation and information systems conference proceedings. 6th international VNIS. A ride into the future

Publication Date

January 1, 1995
Suggested Citation
C. Sun and S.G. Ritchie (1995) “Simulated field test of open architecture transportation controller software”, in Pacific rim TransTech conference. 1995 vehicle navigation and information systems conference proceedings. 6th international VNIS. A ride into the future. IEEE, pp. 414–419. Available at: 10.1109/vnis.1995.518870.