conference paper
published journal article
Structural equation models are developed that explain driver allocation and annual vehicle use in terms of characteristics of the household and its vehicle(s). Separate models are estimated for one-vehicle and multi-vehicle households using both observed and stated preference data from a 1993 survey in California. Results quantify how use decreases as vehicles age, and it is predicted that electric and other limited range vehicles will be used less than conventional fuel vehicles. In multi-vehicle households, shifts in use are detected between vehicles of different ages, operating costs and fuel types. /// Es werden Strukturgleichungsmodelle entwickelt, die den jährlichen Fahrzeuggebrauch von Fahrern in Abhängigkeit von bestimmten Haushaltsmerkmalen und von dem (den) zur Verfügung stehenden Fahrzeugtyp(en) erklären. Sowohl für Haushalte mit nur einem Fahrzeug als auch für solche mit mehreren Fahrzeugen werden verschiedene Modelle auf Basis von Daten zu beobachteten und bekundeten Präferenzen aus einer Umfrage in Kalifornien aus dem Jahr 1993 geschätzt. Die Resultate zeigen, daß die Nutzung mit steigendem Fahrzeugalter abnimmt. Voraussichtlich werden elektrische und andere Fahrzeuge mit eingeschränkter Reichweite weniger genutzt werden als Fahrzeuge mit konventionellen Antriebstechniken. In Haushalten mit mehreren Fahrzeugen werden Nutzungsschwankungen zwischen Fahrzeugen unterschiedlichen Alters, unterschiedlicher Betriebskosten und Art des Brennstoffs ausgemacht. /// Des modèles d’équations des structures sont développés pour expliquer l’affection de conducteur et l’utilisation annuelle des véhicules en fonction des caractéristiques du foyer et de son ou ses véhicules. Des modèles différents sont utilisés pour les foyers possédant un ou plusieurs véhicules, avec pour base des données sur le “revealed preference” et le “stated preference” d’une étude menée en Californie en 1993. Les résultats montrent que l’utilisation du véhicule diminue avec l’âge, et on prévoit que les véhicules électriques ou à fable rayon d’action seront moins utilisés que les véhicules à carburant conventionnel. Dans les foyers possédant plusieurs véhicules, on note des changements dans l’utilisation des véhicules selon l’âge, les frais d’exploitation et le type de carburant utilisé. /// Se desarrollan modelos de ecuaciones estructurales para explicar la asignación de conductores y el uso anual de vehí culos en función de las caracterí sticas de las familias y su(s) vehí culo(s). Se estiman modelos independientes para familias con un vehí culo y familias con varios vehí culos mediante el uso de datos de preferencia revelada y manifiesta a partir de una encuesta realizada en California en 1993. Los resultados cuantifican cómo el uso decrece con la edad del vehí culo y se predice que los vehí culos eléctricos y de serie limitada se usarán menos que los vehí culos de carburante convencional. En familias con varios vehí culos, se detectan cambios en la utilización de vehí culos de diferentes edades, costes operativos y tipos de carburante.
working paper
A review of the literature on the issue of the cost structure of bus transport shows that most studies use simplistic analytical constructs which do not allow for analysis of relationships between production cost on the one hand and output and input factor prices on the other. In particular, the demand for factors of production, factor substitution and price elasticities are not investigated. This study uses a two factors translog cost function model, which is subject to very few a priori economic restrictions, to investigate these issues. By using a data base which represents the Israeli bus sector, the empirical results provide a comprehensive description of the cost structure of the sector. These results include scale economies, fixed factor proportions-type production technology; non-linear separability of factors in cost function, and small own price elasticity of demand for labor relative to capital.
conference paper
research report
This report examines the market share of cleaner technologies and lower carbon intensive fuel use among heavy-duty vehicles (HDVs) and off-road equipment (ORE) to better understand how regulatory measures and incentive programs have and can affect the market. It also projects the uptake of technology for low-carbon transportation (LCT) and identifies the technical features that could potentially improve and optimize the energy demands of both HDVs and ORE under various operational conditions. The research team was led by Principal Investigator (PI) Professor Stephen Ritchie of the University of California, Irvine’s (UCI) Institute of Transportation Studies (ITS), in collaboration with Professor Scott Samuelsen from UCI’s Advanced Power and Energy Program. Research partners Dr. Bo Liu from the University of California, Los Angeles, (UCLA), Dr. Kanok Boriboonsomsin and Fuad Un-Noor from University of California Riverside (UCR), and Suman Mitra from the University of Arkansas (UARK). In order to identify barriers to uptake of LCT, the research team conducted an analysis of existing market survey and real-world operation data of heavy-duty fleets and ORE participating in incentive programs. More incentive programs exist for HDVs; thus, lessons learned were extrapolated to OREs and that sector’s unique challenges to increasing the market share of clean technology were identified. The project also examined incentive programs as a whole and quantified socioeconomic, environmental, and health impacts as a function of incentive dollars spent on clean technology adoption. Using the market data, as well as inputs from other research projects, this project delivered a tool that forecasts low-carbon transportation technology market penetration between 2020 and 2050 that considers incremental cost, projected availability of low-carbon fuel sources, estimated reduction of criteria pollutants, and GHG emissions. Finally, this project estimated the year in which low-carbon transportation technology solutions reach cost parity or market acceptance relative to conventional technologies without incentive program supports.
Video Presentation |
Jun 2024
conference paper
Predicting the future trajectories of surrounding vehicles based on their history trajectories is a critical task in autonomous driving. However, when small crafted perturbations are introduced to those history trajectories, the resulting anomalous (or adversarial) trajectories can significantly mislead the future trajectory prediction module of the ego vehicle, which may result in unsafe planning and even fatal accidents. Therefore, it is of great importance to detect such anomalous trajectories of the surrounding vehicles for system safety, but few works have addressed this issue. In this work, we propose two novel methods for learning effective and efficient representations for online anomaly detection of vehicle trajectories. Different from general time-series anomaly detection, anomalous vehicle trajectory detection deals with much richer contexts on the road and fewer observable patterns on the anomalous trajectories themselves. To address these challenges, our methods exploit contrastive learning techniques and trajectory semantics to capture the patterns underlying the driving scenarios for effective anomaly detection under supervised and unsupervised settings, respectively. We conduct extensive experiments to demonstrate that our supervised method based on contrastive learning and unsupervised method based on reconstruction with semantic latent space can significantly improve the performance of anomalous trajectory detection in their corresponding settings over various baseline methods. We also demonstrate our methods’ generalization ability to detect unseen patterns of anomalies.
conference paper
working paper
This report presents a micro-simulation method to evaluate potential ITS applications. Based on the commercial PARAMICS model, a capability-enhanced PARAMICS simulation environment has been developed through integrating a number of plug- in modules implemented with Application Programming Interfaces (API). This enhanced PARAMICS simulation can thus have capabilities to model not only the target traffic conditions and operations but also various potential ITS strategies. An evaluation study on the effectiveness of potential ITS strategies under the incident scenarios is conducted over a corridor network located at the city of Irvine, California. The potential ITS strategies include incident management, local adaptive ramp metering, coordinated ramp metering, traveler information systems, and the combination of above. Based on the calibrated simulation model, we implement and evaluate these scenarios. The evaluation results show that all ITS strategies have positive effects on the network performance. Because of the network topology (one major freeway with two parallel arterial streets), real-time traveler information system has the greatest benefits among all single ITS components. The combination of several ITS components, such as the corridor control and the combination scenarios, can generate better benefits.
published journal article
published journal article
An abstract is unavailable.