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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

An Evaluation of Eight Class B School Transportation Systems of Wise County, Texas

Braboy, John Robert 08 1900 (has links)
The problem of this study is to determine the efficiency of the transportation systems of eight Class B schools of Wise County, Texas.
112

From selfish to social optimal planning for cooperative autonomous vehicles in transportation systems

Chavez Armijos, Andres S. 11 September 2024 (has links)
Connected and Automated Vehicles (CAVs) have the potential to revolutionize transportation efficiency and safety through collaborative behavior. This dissertation explores the challenges and opportunities associated with achieving socially optimal cooperative maneuvers, using the problem of cooperative lane-changing to showcase the significance of cooperativeness. Cooperative lane-changing serves as an ideal testbed for examining decentralized optimal control, interactions with uncooperative vehicles, accommodating diverse human driving preferences, and integrating planning and execution processes. Initially, the research focuses on scenarios where all vehicles are cooperative CAVs, leveraging their communication and coordination capabilities. Decentralized optimal control problems are formulated to minimize energy consumption, travel time, and traffic disruption during sequential cooperative lane changes, balancing individual vehicle objectives with system-level goals. The dissertation then extends the analysis to mixed-traffic scenarios involving uncooperative human-driven vehicles (HDVs). A novel approach is developed to ensure safety assurance, combining optimal control with Control Barrier Functions (CBFs) and fixed-time convergence (FxT-OCBF). Robust methods for handling disturbances from uncooperative vehicles are introduced, enhancing the resilience and dependability of cooperative lane-changing maneuvers. An innovative online learning framework is presented to address the complexities of CAVs interacting with HDVs exhibiting diverse driving preferences. Safety preferences are characterized using parameterized CBFs, and an extended Kalman filter dynamically adjusts control parameters based on observed interactions, enabling real-time adaptation to evolving human behaviors. The proposed methodologies bridge the gap between high-level planning and low-level control execution, facilitating safe and near-optimal cooperative maneuvers. Comprehensive analysis demonstrates improved traffic throughput, reduced energy consumption, and enhanced safety compared to non-cooperative or reactive approaches. This research lays the foundation for deploying CAV technologies that prioritize social optimality while addressing uncertainties in mixed-traffic settings, ultimately paving the way for safer and more efficient transportation systems. / 2025-03-11T00:00:00Z
113

Effectiveness of Intelligent Transportation Systems on Utah Roadways

Davis, Matthew Cline 07 December 2023 (has links) (PDF)
This thesis presents the findings of a comprehensive research study conducted for the Utah Department of Transportation (UDOT) to evaluate the effectiveness of commonly deployed Intelligent Transportation System (ITS) treatments in Utah, with a focus on Variable Message Signs (VMS), traffic cameras, and Road Weather Information System(s) (RWIS) sites. The study aimed to determine the impact of these ITS treatments on mobility and safety for Utah's unique road conditions and configurations. Three primary analyses were performed: a diversion rates analysis to assess the effectiveness of VMS on Utah freeways during incidents; a weather analysis to evaluate the effectiveness of VMS messages on driver speeds in Utah canyons during winter weather; and an ITS attitudes survey to gauge the usage of, attitudes towards, and potential improvements to UDOT's current ITS deployment. The findings of the diversion rates analysis indicate that the activation of VMS messages increase diversion rates by 18 percent and from the weather analysis, a negligible increase of speeds by 0.2 mph was observed. Survey results were largely positive with a high level of ITS usage and benefits reported by UDOT employees. Concerns of general device wear and maintenance were documented. The report provides detailed methodologies, results, conclusions, and recommendations derived from this research, offering valuable insights to guide UDOT's ITS deployment strategies.
114

Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues

Ala, Mani Venkat Sai Kumar 22 March 2016 (has links)
Traffic signals typically produce vehicle stops and thus increase vehicle fuel consumption levels. Vehicle stops produced by traffic signals, decrease vehicle fuel economy on arterial roads making it significantly lower than that on freeways. Eco-Cooperative Adaptive Cruise Control (Eco-CACC) systems can improve vehicle fuel efficiency by receiving Signal Phasing and Timing (SPaT) data form downstream signalized intersections via vehicle-to-infrastructure communication. The algorithm that was developed in an earlier study provides advisory speed recommendations to drivers to reduce vehicle fuel consumption levels in the vicinity of traffic signalized intersections. The research presented in this thesis enhances the algorithm by adding a queue length estimation component and incorporates the algorithm in the INTEGRATION microscopic traffic simulation software to test the system under varying conditions. The enhanced Eco-CACC algorithm is then tested in a simulation environment considering different levels of connected vehicle (CV) market penetration levels. The simulation analysis demonstrates that the algorithm is able to reduce the vehicle fuel consumption level by as high as 40%. Moreover, the overall benefits of the proposed algorithm is evaluated for different intersection configurations and CV market penetration rates (MPRs). The results demonstrate that for single lane approaches, the algorithm can reduce the overall fuel consumption levels and that higher MPRs result in larger savings. While for multilane approaches, lower MPRs produce negative impacts on fuel efficiency; only when MPRs are greater than 30%, can the algorithm work effectively in reducing fuel consumption levels. Subsequently a sensitivity analysis is conducted. The sensitivity analysis demonstrates that higher market penetration rates of Eco-CACC enabled vehicles can improve the environmental benefits of the algorithm, and the overall savings in fuel consumption are as high as 19% when all vehicles are equipped with the system. While, on multi-lane approaches, the algorithm has negative impacts on fuel consumption levels when the market penetration rate is lower than 30 percent. The analysis also indicates that the length of control segments, the SPaT plan, and the traffic demand levels affect the algorithm performance significantly. The study further demonstrates that the algorithm has negative impacts on fuel consumption levels when the network is over-saturated. / Master of Science
115

Platoon modal operations under vehicle autonomous adaptive cruise control model

Yan, Jingsheng 10 July 2009 (has links)
This paper presents a theoretical development of adaptive cruise control models and platoon operation logic for Automated Highway Systems in the Advanced Vehicle Control Systems (AVeS). Three control modes, constant speed, emergency and vehicle-following, are defined based on the minimum safe stopping distance, and applied to the platoon operations. Desired acceleration model is built for the different cruise control mode by considering the relative velocity, the difference between the relative distance and desired spacing, and the acceleration of the preceding vehicle. A control system model is proposed based on the analysis of vehicle dynamics. The contribution of uncontrolled forces from the air, slop and friction to the vehicle acceleration is considered. Application of control models for two successive vehicles is simulated under the situations of speed transition and emergency stopping. Proper control parameters are determined for different operation mode subject to the conditions: collision avoidance and stability. Same criteria are utilized to the platoon simulation in which the operation logic is regulated so that the platoon leader is operated under either emergency mode or constant speed mode depending upon the . distance from the downstream vehicle, while the intraplatoon vehicles are forced to operate under vehicle-following mode. Three cases under speed transition, emergency stopping and platoon leader splitting are simulated to determine the stable control parameters. Lane capacity analysis shows the tradeoff between safety and efficiency for platoon. modal operations on freeway with guideline or automated highway. / Master of Science
116

A LIGHTWEIGHT CAMERA-LIDAR FUSION FRAMEWORK FOR TRAFFIC MONITORING APPLICATIONS / A CAMERA-LIDAR FUSION FRAMEWORK

Sochaniwsky, Adrian January 2024 (has links)
Intelligent Transportation Systems are advanced technologies used to reduce traffic and increase road safety for vulnerable road users. Real-time traffic monitoring is an important technology for collecting and reporting the information required to achieve these goals through the detection and tracking of road users inside an intersection. To be effective, these systems must be robust to all environmental conditions. This thesis explores the fusion of camera and Light Detection and Ranging (LiDAR) sensors to create an accurate and real-time traffic monitoring system. Sensor fusion leverages complimentary characteristics of the sensors to increase system performance in low- light and inclement weather conditions. To achieve this, three primary components are developed: a 3D LiDAR detection pipeline, a camera detection pipeline, and a decision-level sensor fusion module. The proposed pipeline is lightweight, running at 46 Hz on modest computer hardware, and accurate, scoring 3% higher than the camera-only pipeline based on the Higher Order Tracking Accuracy metric. The camera-LiDAR fusion system is built on the ROS 2 framework, which provides a well-defined and modular interface for developing and evaluated new detection and tracking algorithms. Overall, the fusion of camera and LiDAR sensors will enable future traffic monitoring systems to provide cities with real-time information critical for increasing safety and convenience for all road-users. / Thesis / Master of Applied Science (MASc) / Accurate traffic monitoring systems are needed to improve the safety of road users. These systems allow the intersection to “see” vehicles and pedestrians, providing near instant information to assist future autonomous vehicles, and provide data to city planers and officials to enable reductions in traffic, emissions, and travel times. This thesis aims to design, build, and test a traffic monitoring system that uses a camera and 3D laser-scanner to find and track road users in an intersection. By combining a camera and 3D laser scanner, this system aims to perform better than either sensor alone. Furthermore, this thesis will collect test data to prove it is accurate and able to see vehicles and pedestrians during the day and night, and test if runs fast enough for “live” use.
117

Modeling multiple route choice paradigms under different types and levels of ATIS using correlated data

Abdalla, Mohamed Fathy 01 October 2003 (has links)
No description available.
118

Use of microsimulation to access HCM2010 methodology for oversaturated freeway segments

Unknown Date (has links)
Highway Capacity Manual (HCM) 2010 methodology for freeway operations contain procedures for calculating traffic performance measures both for undersaturated and oversaturated flow conditions. However, one of the limitations regarding oversaturated freeway weaving segments is that the HCM procedures have not been extensively calibrated based on field observations on U.S. freeways. This study validates the HCM2010 methodology for oversaturated freeway weaving segment by comparing space mean speed and density obtained from HCM procedure to those generated by a microsimulation model. A VISSIM model is extensively calibrated and validated based on NGSIM field data for the US 101 Highway. Abundance of the NGSIM data is utilized to calibrate and validate the VISSIM model. Results show that HCM methodology has significant limitations and while in some cases it can reproduce density correctly, the study finds that speeds estimated by the HCM methodology significantly differ from those observed in the field. / by Dusan Jolovic. / Thesis (M.S.C.S.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web.
119

Méthodes coopératives de localisation de véhicules / Cooperative methods for vehicle localization

Rohani, Mohsen January 2015 (has links)
Abstract : Embedded intelligence in vehicular applications is becoming of great interest since the last two decades. Position estimation has been one of the most crucial pieces of information for Intelligent Transportation Systems (ITS). Real time, accurate and reliable localization of vehicles has become particularly important for the automotive industry. The significant growth of sensing, communication and computing capabilities over the recent years has opened new fields of applications, such as ADAS (Advanced driver assistance systems) and active safety systems, and has brought the ability of exchanging information between vehicles. Most of these applications can benefit from more accurate and reliable localization. With the recent emergence of multi-vehicular wireless communication capabilities, cooperative architectures have become an attractive alternative to solving the localization problem. The main goal of cooperative localization is to exploit different sources of information coming from different vehicles within a short range area, in order to enhance positioning system efficiency, while keeping the cost to a reasonable level. In this Thesis, we aim to propose new and effective methods to improve vehicle localization performance by using cooperative approaches. In order to reach this goal, three new methods for cooperative vehicle localization have been proposed and the performance of these methods has been analyzed. Our first proposed cooperative method is a Cooperative Map Matching (CMM) method which aims to estimate and compensate the common error component of the GPS positioning by using cooperative approach and exploiting the communication capability of the vehicles. Then we propose the concept of Dynamic base station DGPS (DDGPS) and use it to generate GPS pseudorange corrections and broadcast them for other vehicles. Finally we introduce a cooperative method for improving the GPS positioning by incorporating the GPS measured position of the vehicles and inter-vehicle distances. This method is a decentralized cooperative positioning method based on Bayesian approach. The detailed derivation of the equations and the simulation results of each algorithm are described in the designated chapters. In addition to it, the sensitivity of the methods to different parameters is also studied and discussed. Finally in order to validate the results of the simulations, experimental validation of the CMM method based on the experimental data captured by the test vehicles is performed and studied. The simulation and experimental results show that using cooperative approaches can significantly increase the performance of the positioning methods while keeping the cost to a reasonable amount. / Résumé : L’intelligence embarquée dans les applications véhiculaires devient un grand intérêt depuis les deux dernières décennies. L’estimation de position a été l'une des parties les plus cruciales concernant les systèmes de transport intelligents (STI). La localisation précise et fiable en temps réel des véhicules est devenue particulièrement importante pour l'industrie automobile. Les améliorations technologiques significatives en matière de capteurs, de communication et de calcul embarqué au cours des dernières années ont ouvert de nouveaux champs d'applications, tels que les systèmes de sécurité active ou les ADAS, et a aussi apporté la possibilité d'échanger des informations entre les véhicules. Une localisation plus précise et fiable serait un bénéfice pour ces applications. Avec l'émergence récente des capacités de communication sans fil multi-véhicules, les architectures coopératives sont devenues une alternative intéressante pour résoudre le problème de localisation. L'objectif principal de la localisation coopérative est d'exploiter différentes sources d'information provenant de différents véhicules dans une zone de courte portée, afin d'améliorer l'efficacité du système de positionnement, tout en gardant le coût à un niveau raisonnable. Dans cette thèse, nous nous efforçons de proposer des méthodes nouvelles et efficaces pour améliorer les performances de localisation du véhicule en utilisant des approches coopératives. Afin d'atteindre cet objectif, trois nouvelles méthodes de localisation coopérative du véhicule ont été proposées et la performance de ces méthodes a été analysée. Notre première méthode coopérative est une méthode de correspondance cartographique coopérative (CMM, Cooperative Map Matching) qui vise à estimer et à compenser la composante d'erreur commune du positionnement GPS en utilisant une approche coopérative et en exploitant les capacités de communication des véhicules. Ensuite, nous proposons le concept de station de base Dynamique DGPS (DDGPS) et l'utilisons pour générer des corrections de pseudo-distance GPS et les diffuser aux autres véhicules. Enfin, nous présentons une méthode coopérative pour améliorer le positionnement GPS en utilisant à la fois les positions GPS des véhicules et les distances inter-véhiculaires mesurées. Ceci est une méthode de positionnement coopératif décentralisé basé sur une approche bayésienne. La description détaillée des équations et les résultats de simulation de chaque algorithme sont décrits dans les chapitres désignés. En plus de cela, la sensibilité des méthodes aux différents paramètres est également étudiée et discutée. Enfin, les résultats de simulations concernant la méthode CMM ont pu être validés à l’aide de données expérimentales enregistrées par des véhicules d'essai. La simulation et les résultats expérimentaux montrent que l'utilisation des approches coopératives peut augmenter de manière significative la performance des méthodes de positionnement tout en gardant le coût à un montant raisonnable.
120

Cloud computing based adaptive traffic control and management

Jaworski, P. January 2013 (has links)
Recent years have shown a growing concern over increasing traffic volume worldwide. The insufficient road capacity and the resulting congestions have become major problems in many urban areas. Congestions negatively impact the economy, the environment and the health of the population as well as the drivers satisfaction. Current solutions to this topical and timely problem rely on the exploitation of Intelligent Transportation Systems (ITS) technologies. ITS urban traffic management involves the collection and processing of a large amount of geographically distributed information to control distributed infrastructure and individual vehicles. The distributed nature of the problem prompted the development of a novel, scalable ITS-Cloud platform. The ITS-Cloud organises the processing and manages distributed data sources to provide traffic management methods with more accurate information about the state of the traffic. A new approach to service allocation, derived from the existing cloud and grid computing approaches, was created to address the unique needs of ITS traffic management. The ITS-Cloud hosts the collection of software services that form the Cloud based Traffic Management System (CTMS). CTMS combines intersection control algorithms with intersection approach advices to the vehicles and dynamic routing. The CTMS contains a novel Two-Step traffic management method that relies on the ITS-Cloud to deliver a detailed traffic simulation image and integrates an adaptive intersection control algorithm with a microscopic prediction mechanism. It is the first method able to perform simultaneous adaptive intersection control and intersection approach optimization. The Two-Step method builds on a novel pressure based adaptive intersection control algorithm as well as two new traffic prediction schemes. The developed traffic management system was evaluated using a new microscopic traffic simulation tool tightly integrated with the ITS-Cloud. The novel traffic management approaches were shown to outperform benchmark methods for a realistic range of traffic conditions and road network configurations. Unique to the work was the investigation of interactions between ITS components.

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