working paper

On the Structure of Weekly Activity/Travel Patterns

Publication Date

September 1, 2003

Author(s)

Ming-Sheng Lee, Michael McNally

Working Paper

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

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View working paper

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.

Phd Dissertation

Cellular signals for navigation 4g, 5g, and beyond

Publication Date

December 1, 2023

Author(s)

Ali Abdallah

Areas of Expertise

Intelligent Transportation Systems, Emerging Technologies, & Big Data

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Abstract

Global Navigation Satellite Systems (GNSSs) have long been the cornerstone for positioning, navigation, and timing. Despite their widespread use, GNSS signals face vulnerabilities such as jamming, spoofing, and unreliable coverage in various environments like urban canyons, indoors, tunnels, and parking structures. These limitations make exclusive reliance on GNSS inadequate for the rigorous demands of future applications, including autonomous vehicles (AVs), intelligent transportation systems, and location-based services. To enhance GNSS performance in challenging settings, traditional methods have typically incorporated dead-reckoning sensors like inertial measurement units, lidars, or cameras. These sensors, however, accumulate errors over time and only offer navigation solutions within a local frame, relative to the user equipment’s (UE) initial position. In contrast, alternative signal-based approaches, known as signals of opportunity (SOPs) – encompassing AM/FM radio, satellite communication signals, digital television signals, Wi-Fi, and cellular – hold considerable promise as global navigation sources in GNSS-challenged environments. Among SOPs, cellular signals, particularly from third-generation (3G, code-division multiple access (CDMA)), fourth-generation (4G, long-term evolution (LTE)), and fifth-generation (5G, new radio (NR)) networks, stand out as potential navigation aids. Their navigation-friendly characteristics include ubiquity, geometric diversity, high carrier frequencies, spectral diversity, spatial diversity, broad bandwidth, strong signal strength, and free accessibility. Nevertheless, as SOPs are primarily designed for communication rather than navigation, utilizing cellular signals for navigational purposes presents several challenges. These include (1) the lack of specific low-level signal and error models for optimal state and parameter extraction for positioning and timing, (2) the absence of published robust, efficient, and reliable receiver architectures to generate navigation observables, (3) continual updates and changes in cellular protocols, and (4) the scarcity of frameworks for high-accuracy navigation using such signals. This dissertation addresses these challenges, focusing on cellular signals from 4G and 5G networks, with potential extensions to future cellular systems. The foundational contributions of this work are empirically validated on various platforms including ground vehicles (GVs), unmanned aerial vehicles (UAVs), and high-altitude aircraft, demonstrating GNSS-level navigation accuracy.

Suggested Citation

Ali Abdallah (2023) Cellular signals for navigation 4g, 5g, and beyond. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/17uq3m8/alma991035582060804701.

Related Publications

research report | Nov 2023

CARMEN Project 6: PNT with Signals of Opportunity and Real-World Jammed and Spoofed Environments

Phd Dissertation | Jan 2024

Hardware/software co-design methodologies for efficient ai systems and applications

Phd Dissertation | Sep 2024

Exploring novel security vulnerabilities and their safety implications in sensors and perception for autonomous systems

conference paper

Joint design of multimodal transit networks and shared autonomous mobility fleets

Proceedings of the 98th annual meeting of the transportation research board

Publication Date

January 1, 2019

Author(s)

Helen Pinto, Michael Hyland, Hani Mahmassani, öMer Verbas

Abstract

Providing quality transit service to travelers in low-density areas, particularly travelers without personal vehicles, is a constant challenge for transit agencies. The advent of fully-autonomous vehicles (AVs) and their inclusion in mobility service fleets may allow transit agencies to offer travelers better service and/or reduce their own capital and operational costs. This study focuses on the problem of allocating resources between transit patterns and operating (or subsidizing) shared-use AV mobility services (SAMSs) in a large metropolitan area. To address this problem, a bi-level mathematical programming formulation and solution algorithm are presented for the joint transit network redesign and SAMS fleet size determination problem (JTNR-SFSDP). The upper-level problem modifies a transit network frequency setting problem (TNFSP) formulation via incorporating SAMS fleet size as a decision variable. The lower-level problem consists of a dynamic combined mode choiceâ??traveler assignment problem (DCMC-TAP) formulation. The solution procedure involves solving the upper-level problem using a nonlinear programming solver and solving the lower-level problem using an iterative agent-based simulation-assignment approach. To illustrate the effectiveness of the modeling framework, this study uses traveler demand from Chicago along with the regionâ??s existing multimodal transit network. The results indicate the ability of the solution procedure to solve the bi-level JTNR-SFSDP. Moreover, computational results indicate significant traveler benefits associated with optimizing the joint design of multimodal transit networks and SAMS fleets.

Suggested Citation

Helen Pinto, Michael Hyland, Hani S. Mahmassani and Ömer Verbas (2019) “Joint design of multimodal transit networks and shared autonomous mobility fleets”, in Proceedings of the 98th annual meeting of the transportation research board, p. 7p.

working paper

The Century Freeway/Transitway I-105: Nucleation, Land Use Changes and Transportation Behavior

Publication Date

June 1, 1995

Author(s)

Joseph Dimento, Drusilla van Hengel, Sherry Ryan

Working Paper

UCI-ITS-WP-95-10

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

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Abstract

The Glenn M. Anderson Freeway/Transitway project includes six lanes for general traffic, two HOV lanes, and the Green Line, a light rail project with ten transit stations and park and ride lots. The 17.2 mile facility traverses eleven jurisdictions and serves these and other neighboring communities. The study analyzes transportation attitudes and behavior before and after the opening of both the freeway and before the transitway opening. We measure travel behavior impacts of the new transportation system using a panel study. The attitudes and intended use of the facility as well as a 24 hour travel diary. Also investigated land use around transit nodes and local freeway interchanges by measuring zoning changes, reviewing general plans and other documents, and interviewing local planning officials.

Suggested Citation

Joseph F. DiMento, Drusilla R. van Hengel and Sherry Ryan (1995) The Century Freeway/Transitway I-105: Nucleation, Land Use Changes and Transportation Behavior. Working Paper UCI-ITS-WP-95-10. Institute of Transportation Studies, Irvine. Available at: https://escholarship.org/uc/item/5n56s5sr.

conference paper

Prioritization of potential alternative truck management strategies using the analytical hierarchy process

Proceedings of the 88th annual meeting of the transportation research board

Publication Date

January 1, 2009

Author(s)

Choong Heon Yang, Amelia Regan

Abstract

This study develops a decision-making framework for prioritizing potential alternative truck management strategies. The motivation of this study is derived from the need to evaluate likely impacts resulting from the implementation of these strategies. Two main objectives are accomplished in this study. The first part of the study develops a decision making framework which is capable of prioritizing potential alternatives truck management strategies using the Analytical Hierarchy Process. This enables the judgments and preferences of decision-makers to be quantified based on the relative importance of their individual criteria, and to allow quantitative interpretation from others. The second part of the study provides a specific example of how to prioritize potential alternative truck strategies using a case study. A PARAMICS simulation model is used as the main analytical tool to analyze quantitative impacts of these strategies. The framework includes various measures that can and cannot be directly transformed into monetary costs in order to reflect the standpoints of both the public and the private sectors. Another important contribution of the study is to develop a 100-score conversion formula as a normalization technique. Since quantitative measurements have different scales, the authors need to incorporate these measurements into a single value. This method allows decision-makers to easily facilitate comparisons among potential alternatives when the final decisions are made.

Suggested Citation

Choon Heon Yang and Amelia Regan (2009) “Prioritization of potential alternative truck management strategies using the analytical hierarchy process”, in Proceedings of the 88th annual meeting of the transportation research board, p. 22p.

Preprint Journal Article

Impact Evaluation of Falsified Data Attacks on Connected Vehicle Based Traffic Signal Control

Publication Date

October 9, 2020

Author(s)

Shihong Ed Huang, Wai Wong, Yiheng Feng, Qi Alfred Chen, Z. Morley Mao, Henry Liu

Report Number

arXiv:2010.04753

View Preprint Journal Article

Abstract

Connected vehicle (CV) technology enables data exchange between vehicles and transportation infrastructure and therefore has great potentials to improve current traffic signal control systems. However, this connectivity might also bring cyber security concerns. As the first step in investigating the cyber security of CV-based traffic signal control (CV-TSC) systems, potential cyber threats need to be identified and corresponding impact needs to be evaluated. In this paper, we aim to evaluate the impact of cyber attacks on CV-TSC systems by considering a realistic attack scenario in which the control logic of a CV-TSC system is unavailable to attackers. Our threat model presumes that an attacker may learn the control logic using a surrogate model. Based on the surrogate model, the attacker may launch falsified data attacks to influence signal control decisions. In the case study, we realistically evaluate the impact of falsified data attacks on an existing CV-TSC system (i.e., I-SIG).

Suggested Citation

Shihong Ed Huang, Wai Wong, Yiheng Feng, Qi Alfred Chen, Z. Morley Mao and Henry X. Liu (2020) “Impact Evaluation of Falsified Data Attacks on Connected Vehicle Based Traffic Signal Control”. arXiv. Available at: http://arxiv.org/abs/2010.04753 (Accessed: October 11, 2023).

conference paper

Under Pressure: Effectiveness and Usability of the Apple Pencil as a Biometric Authentication Tool

Proceedings 2024 Symposium on Usable Security

Publication Date

January 1, 2024

Author(s)

Elina Van Kempen, Zane Karl, Richard Deamicis, Qi Alfred Chen

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Suggested Citation

Elina Van Kempen, Zane Karl, Richard Deamicis and Qi Alfred Chen (2024) “Under Pressure: Effectiveness and Usability of the Apple Pencil as a Biometric Authentication Tool”, in Proceedings 2024 Symposium on Usable Security. Symposium on Usable Security, San Diego, CA, USA: Internet Society. Available at: 10.14722/usec.2024.23056.

Phd Dissertation

Commuting behavior of two-worker households in the Los Angeles Metropolitan Area

Publication Date

June 30, 1993

Associated Project

UCTC Fellowships (ISTEA)

Author(s)

Seyoung Kim

Areas of Expertise

Travel Behavior, Land Use, & the Built Environment

View Phd Dissertation

Abstract

This is the first study that analyzes two-worker and single-worker households’ commuting behavior in the Los Angeles Metropolitan Areas. This study uses “Excess commuting” to test how important commuting distance is for urban workers to choose their residential and job locations in Los Angeles area. Individual location data used are from the Transit Panel Study Survey, 1991. The results show that commuting distance is still an important factor for urban workers to make location decisions, contrary to other study results. I find that if two-worker households’ commuting distance optimization process is restricted by their members job locations, two-worker households’ excess commute is smaller than single-worker households’. Also, the results suggest that spatial mismatch restricts unskilled workers in single-worker households more than it restricts workers from other groups. Further, the results show that the commuting distances of two-worker households are affected more by jobs-housing balance in the region than are the commuting distances of single-worker households. I find that two-worker household males behave differently from two-worker household females, and that two-worker household females behave differently from single-worker household females. I also find that there are sharper gender differences among whites than among nonwhites.

Suggested Citation

Seyoung Kim (1993) Commuting behavior of two-worker households in the Los Angeles Metropolitan Area. PhD Dissertation. UC Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/1go3t9q/alma991035093099204701.

Related Publications

Phd Dissertation | Jun 1995

Citizens near the path of least resistance: Travel behavior of Century Freeway corridor residents

Phd Dissertation | Jun 1995

A microsimulation model for evaluating the environmental impact of alternative-fuel vehicles

Phd Dissertation | Jun 1993

An interactive simulation approach to systematically evaluate the impacts of real-time traffic condition information on driver behavioral choice

Phd Dissertation | Jun 1996

An Activity-Based Approach to Accessibility

Phd Dissertation | Jan 1996

An Empirical Study of Alternative Fuel Vehicle Choice by Commercial Fleets: Lessons in Transportation Choices, and Public Agencies' Organization

conference paper

A Survivability-Aware Cyber-Physical systems design methodology

2019 IEEE 15th international conference on automation science and engineering (CASE)

Publication Date

August 1, 2019

Author(s)

Nafiul Rashid, Gustavo Quiros, Mohammad Al Faruque

View conference paper

Suggested Citation

Nafiul Rashid, Gustavo Quiros and Mohammad Abdullah Al Faruque (2019) “A Survivability-Aware Cyber-Physical systems design methodology”, in 2019 IEEE 15th international conference on automation science and engineering (CASE). IEEE, pp. 848–853. Available at: 10.1109/coase.2019.8843113.

policy brief

Planning Light- and Heavy-Duty ZEV Infrastructure for a More Resilient Fueling Network in California

Publication Date

March 1, 2026

Author(s)

Kate Forrest, Benjamin Hudson, Blake Lane, Scott Samuelsen

View policy brief

Abstract

To meet goals for air quality improvement and greenhouse gas reduction, California aims to expand both light-duty and heavy-duty zero-emission vehicles (ZEVs). To support these aims, the State has set targets for the number of electric charging and hydrogen fueling stations, but deployment is falling short of these targets. For example, there were only 50 hydrogen stations and just over 200,000 chargers as of September 2025, as compared to the goals for this year, set in 2018, of 200 hydrogen stations and 250,000 electric vehicle chargers. Building a large, reliable, equitable network in a short time presents challenges of scale, reliability, and resiliency. One possible way to address these challenges is to combine light-and heavy-duty vehicle charging and fueling infrastructure, given the overlap of these vehicles’ travel patterns and of the respective charging and fueling technologies used. The research investigates how this strategy could support robust charging and refueling networks for projected ZEV growth. To that end, the research also developed a “conservative” and an “optimistic” scenario to simulate charging and hydrogen fueling station deployment across California for 2025, 2035, and 2045.