published journal article
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published journal article
"Wasteful" Commuting: A Resolution
Journal of Political Economy
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Author(s)
Suggested Citation
Kenneth A. Small and Shunfeng Song (1992) “"Wasteful" Commuting: A Resolution”, Journal of Political Economy, 100(4), pp. 888–898. Available at: 10.1086/261844.Phd Dissertation
An Analysis of Carsharing and Battery Electric Vehicles in the United States
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Author(s)
Abstract
According to the California Air Resources Board (CARB, 2020), light-duty vehicles are responsible for 13 percent of statewide NOx emissions and 28 percent of statewide greenhouse gas emissions. Scientists, policymakers, and car manufacturers have been striving to reduce the air pollution and greenhouse gas emissions from the transportation sector using various measures, ranging from cleaner engines to alternatives to driving to reduce VMT. In this dissertation, I focus on a subset of these measures: carsharing programs and Battery Electric Vehicles (BEVs). In the first part of this dissertation, I explore the profile of households engaging in carsharing by estimating zero-inflated negative binomial (ZINB) models on data from the 2017 National Household Travel Survey (NHTS). My results show that households who are more likely to carshare are those who participate in other forms of sharing, have more Silent generation members, are less educated (the highest educational achievement is a high school degree), and have fewer vehicles than drivers. Conversely, households with more young adults (18 – 20 years old), with 2 or more adults and no children, take part in carsharing program less often. Moreover, households who took more part in ridesharing and have fewer vehicles than drivers are less likely to never carshare. Furthermore, households whose annual income between $75,000 and $150,000 are more likely to never carshare. In the second part of this dissertation, I concentrate on the adoption of BEVs. More specifically, I focus on two questions: 1) What are the characteristics of households who own battery electric vehicles (BEVs)?; and 2) Does the travel behavior of these households differ from the travel of households who have motor vehicles but not BEVs? To answer those questions, I characterize three groups of households based on their vehicle holdings: BEV-only, BEV+ (i.e., households with both one or more BEV and at least one conventional vehicle), and non-BEV households. I analyze data from the 2017 NHTS using mixed methods. Results show that BEV households are more likely to be Asian, well-educated, with a higher income and to live in higher population and employment density areas. Furthermore, BEV-only households are more likely to be composed of one adult (not retired) with fewer Baby Boomers. Yet, BEV+ households are more likely to be larger households with 2 or more adults. Also, BEV+ households are more likely to have more Generation X (37-52 years old in 2017) and Z members (20 years old or younger in 2017). They are also more likely to own their home. My analysis on gender (at the individual level) concluded that BEV owners are more likely to be men. Furthermore, I find that BEV households travel as much as non-BEV households. Although carsharing and BEVs could substantially decrease the environmental footprint of transportation, they are currently far from mainstream. To promote carsharing programs, their reach could be extended, they could be made more affordable, while increasing the cost of owning and operating private vehicles. Similarly, state and federal governments could continue to provide financial incentives to lower the purchase price difference between conventional and BE vehicles, manufacturers could provide extended warranties on batteries, and the charging infrastructure needs to be developed in order to attract more customers. The Covid-19 crisis is giving governments around the world an opportunity to invest in clean technologies to jumpstart the economy. It is critical to take advantage of this crisis to reduce air pollution and greenhouse gas emissions from transportation for the good of current and future generations.
Suggested Citation
Yunwen Feng (2021) An Analysis of Carsharing and Battery Electric Vehicles in the United States. Ph.D.. University of California, Irvine. Available at: https://uci.primo.exlibrisgroup.com/permalink/01CDL_IRV_INST/u4evf/cdi_proquest_journals_2555985409 (Accessed: October 12, 2023).conference paper
Impact of VSL location on capacity drop: A case of sag and tunnel bottlenecks
INTERNATIONAL SYMPOSIUM OF TRANSPORT SIMULATION (ISTS'18) AND THE INTERNATIONAL WORKSHOP ON TRAFFIC DATA COLLECTION AND ITS STANDARDIZATION (IWTDCS'18) - EMERGING TRANSPORT TECHNOLOGIES FOR NEXT GENERATION MOBILITY
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Abstract
When there is upstream congestion the discharging flow-rate of a tunnel or sag bottleneck can drop, which leads to additional traffic jams. Therefore, control strategies such as variable speed limit (VSL) have been developed aiming to prevent or mitigate upstream traffic congestion. Understanding traffic dynamics at bottlenecks, especially the mechanism of capacity drop, is critical for developing such models. Many studies are centered on the control algorithm design of VSL. However, there are few studies that systematically anayze the effect that the VSL application area has on the control effectiveness. This paper extends to sag and tunnel bottlenecks the theoretical framework to analytically solve the optimal location of the speed limit application area (first developed in Martinez and Jin (2018)). Moreover, we prove that the optimization formulation can be simplified. Consequently, it can be applied to further bounded acceleration models than the constant one. Finally, for an open-loop control with a constant speed limit for the Kobotonoke tunnel bottleneck, we validate the analytic definition of optimal location by preventing capacity drop in numerical simulations. (C) 2018 The Authors. Published by Elsevier Ltd.
Suggested Citation
Irene Martinez and Wen-Long Jin (2018) “Impact of VSL location on capacity drop: A case of sag and tunnel bottlenecks”, in . Yoshii, T and Shiomi, Y and Kusakabe, T and Wada, K (ed.) INTERNATIONAL SYMPOSIUM OF TRANSPORT SIMULATION (ISTS'18) AND THE INTERNATIONAL WORKSHOP ON TRAFFIC DATA COLLECTION AND ITS STANDARDIZATION (IWTDCS'18) - EMERGING TRANSPORT TECHNOLOGIES FOR NEXT GENERATION MOBILITY. ELSEVIER SCIENCE BV (Transportation research procedia), pp. 12–19. Available at: 10.1016/j.trpro.2018.11.008.working paper
On the Structure of Weekly Activity/Travel Patterns
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Working Paper
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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
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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.conference paper
Joint design of multimodal transit networks and shared autonomous mobility fleets
Proceedings of the 98th annual meeting of the transportation research board
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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
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Author(s)
Working Paper
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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
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Author(s)
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.