Variable Speed Limit (VSL) strategies identify and disseminate dynamic speed limits that are determined to be appropriate based on prevailing traffic conditions, road surface conditions, and weather conditions. This dissertation develops and evaluates a shockwave-based VSL system that uses a heuristic switching logic-based controller with specified thresholds of prevailing traffic flow conditions. The system aims to improve operations and mobility at critical bottlenecks. Before traffic breakdown occurrence, the proposed VSL’s goal is to prevent or postpone breakdown by decreasing the inflow and achieving uniform distribution in speed and flow. After breakdown occurrence, the VSL system aims to dampen traffic congestion by reducing the inflow traffic to the congested area and increasing the bottleneck capacity by deactivating the VSL at the head of the congested area. The shockwave-based VSL system pushes the VSL location upstream as the congested area propagates upstream. In addition to testing the system using infrastructure detector-based data, this dissertation investigates the use of Connected Vehicle trajectory data as input to the shockwave-based VSL system performance. Since the field Connected Vehicle data are not available, as part of this research, Vehicle-to-Infrastructure communication is modeled in the microscopic simulation to obtain individual vehicle trajectories. In this system, wavelet transform is used to analyze aggregated individual vehicles’ speed data to determine the locations of congestion. The currently recommended calibration procedures of simulation models are generally based on the capacity, volume and system-performance values and do not specifically examine traffic breakdown characteristics. However, since the proposed VSL strategies are countermeasures to the impacts of breakdown conditions, considering breakdown characteristics in the calibration procedure is important to have a reliable assessment. Several enhancements were proposed in this study to account for the breakdown characteristics at bottleneck locations in the calibration process. In this dissertation, performance of shockwave-based VSL is compared to VSL systems with different fixed VSL message sign locations utilizing the calibrated microscopic model. The results show that shockwave-based VSL outperforms fixed-location VSL systems, and it can considerably decrease the maximum back of queue and duration of breakdown while increasing the average speed during breakdown.

Für die Entwicklung von Gesamtfahrzeugeigenschaften ist die objektive Beschreibung von Reifencharakteristika unter der Anwendung entsprechenden Bedingungen von wesentlicher Bedeutung. Der hierzu beschriebene, neuartige Prozess zur Reifencharakterisierung gründet sich auf einem definierten Satz objektiver Gesamtfahrzeugkenngrößen, welche mithilfe dedizierter Fahrmanöver identifiziert werden. Der Kern der hybriden Methode besteht in der zweckmäßigen Klassifizierung von Reifencharakteristika nach Struktur- und Reibgrößen. Auf Basis der kinematischen Deformationsmechanismen in der Reifenkontaktfläche und -konstruktion werden analytische Formulierungen für wesentliche Reifencharakteristika hergeleitet. Die Kombination neuer Prüfmethoden auf Flachbahn- und Anhängerprüfständen erlaubt anschließend deren präzise Identifikation. Zur Zusammenführung der autark gemessenen Eigenschaften wird ein analytisches Synthesemodell beschrieben, welches die Parameteridentifikation von empirischen Reifenmodellen erlaubt. Die Validierung der so identifizierten Reifeneigenschaften erfolgt auf der Gesamtfahrzeugebene. Hier bestätigt sich die maßgebliche Verbesserung der Fahrdynamikrechnung im Linear- und Grenzbereich gegenüber dem bisherigen Stand der Technik.

Für die Entwicklung von Gesamtfahrzeugeigenschaften ist die objektive Beschreibung von Reifencharakteristika unter der Anwendung entsprechenden Bedingungen von wesentlicher Bedeutung. Der hierzu beschriebene, neuartige Prozess zur Reifencharakterisierung gründet sich auf einem definierten Satz objektiver Gesamtfahrzeugkenngrößen, welche mithilfe dedizierter Fahrmanöver identifiziert werden. Der Kern der hybriden Methode besteht in der zweckmäßigen Klassifizierung von Reifencharakteristika nach Struktur- und Reibgrößen. Auf Basis der kinematischen Deformationsmechanismen in der Reifenkontaktfläche und -konstruktion werden analytische Formulierungen für wesentliche Reifencharakteristika hergeleitet. Die Kombination neuer Prüfmethoden auf Flachbahn- und Anhängerprüfständen erlaubt anschließend deren präzise Identifikation. Zur Zusammenführung der autark gemessenen Eigenschaften wird ein analytisches Synthesemodell beschrieben, welches die Parameteridentifikation von empirischen Reifenmodellen erlaubt. Die Validierung der so identifizierten Reifeneigenschaften erfolgt auf der Gesamtfahrzeugebene. Hier bestätigt sich die maßgebliche Verbesserung der Fahrdynamikrechnung im Linear- und Grenzbereich gegenüber dem bisherigen Stand der Technik.

Context In the last centuries, we have been generating and building infrastructure at a faster pace than ever before. Simultaneously the costs for labor and construction sectors as road and house building is increasing. This provides room for autonomous machines. The development of infrastructure is accomplished through highly efficient and productive construction machinery that progressively modernizes to form the society. In order to increase the pace of development, both cars and industry are getting more and more automated. Volvo Construction Equipment is exploring the autonomous vehicle space. The new machines complement and perfect the human work with efficiency, reliability, and durability. There is however, a question of trust between the human workers and the autonomous machines, I will in this thesis investigate methods on how to develop trust through communication systems with autonomous machines.   Objectives To create recommendations and solutions for products that build trust between human and automated machines on a construction site.   Method Outcome is reached through a case study exploration with validated learning, meaning that it will incorporate learnings through prototype iterations.   Results The result evaluates how trust could be developed between humans and autonomous machinery at a construction site and how communication methods between these parties could be implemented while maintaining high levels of efficiency and safety.   Conclusion Findings in this thesis indicates that trust is developed over time with reliable systems that provide colleagues with updated information available at any time. The results can be introduced in both today’s and tomorrow’s construction sites at various levels of advanced technology. / Sammanhang De senaste hundra åren har vi gett upphov till att bygga infrastruktur i en snabbare takt än någonsin tidigare. Samtidigt ökar kostnaderna för både arbetskraft och byggsektorer som väg- och bostadsbyggnader. Denna situation ger utrymme för autonoma maskiner. Utvecklingen av infrastruktur sker genom effektiva och produktiva konstruktionsmaskiner som successivt moderniseras för att forma samhället. För att öka utvecklingstakten moderniseras både bilar och industri för att möta en mer automatiserad vardag.  Volvo Construction Equipment undersöker det autonoma fordonsutrymmet för nästa generations maskiner. Automationen kompletterar de nya maskinerna och fulländar det mänskliga arbetet med effektivitet, tillförlitlighet och hållbarhet.   Det finns dock en fråga om relationen mellan mänskliga arbetare och autonoma maskiner, jag kommer i denna avhandling undersöka metoder för hur man kan utveckla tillit genom kommunikationssystem mellan arbetare och autonoma maskiner.   Mål Att skapa rekommendationer och lösningar för produkter som bygger tillit mellan mänskliga och automatiserade maskiner på en byggarbetsplats.   Metod Resultatet uppnås genom användandet av fallstudie forskning kombinerat med validerande lärande. Detta innebär lärdomar med hjälp av en iterativ process utav prototyper som testas och valideras.   Resultat Resultatet utvärderar hur förtroende kan utvecklas mellan människor och autonoma maskiner på en byggarbetsplats. Hur kommunikationsmetoder mellan dessa parter skulle kunna genomföras samtidigt som hög effektivitet och säkerhet upprätthålls .   Slutsats Lärandet i denna avhandling tyder på att förtroendet utvecklas över tid med tillförlitliga system som ger medarbetare uppdaterad nödvändig information tillgänglig när som helst. Resultaten kan införas i både dagens och framtidens anläggningsplatser på olika nivåer av avancerad teknik. / <p>Vissa delar är borttagan på grund av konfidentialitet.</p> / ME310 Design Innovation at Stanford University

Over the last decade, extensive research efforts have been placed on performance evaluation and the benefits of innovative CV applications. Findings indicate that CV technology can effectively mitigate the safety, mobility, and environmental challenges experienced on transportation networks. Most of research evaluated CV technology through simulation studies. However, a field study provides a more ideal method of assessing CV technology effectiveness. Therefore, a field study to obtain the actual effectiveness of CV technology was warranted, to validate previous findings, and to add to the body of knowledge surrounding this topic. This thesis presents both a field study and simulation evaluation of the effectiveness of CV smartphone technology on a 1.1 mile segment of State Road 121, containing five intersections, in Gainesville, Florida. Field observations were conducted using a CV application, developed by Connected Signals, Inc., that uses a smartphone application, called EnLighten, to communicate intersection information to driver’s smartphone, which serves as a vehicle on-board unit. Traffic operation and safety performance was evaluated using start-up lost time, discharge distribution model, and speed harmonization. Findings show that the CV smartphone technology improved intersection performance with a reduction in start-up lost time of approximately 86%. Additionally, driving safety improved with a reduction in speed variability by nearly 61% between vehicles in a specific lane for a 100% CV penetration rate. Cost analyses of deploying CV smartphone technology indicate that implementation may result in an average total economic cost savings associated with crashes of nearly $6.8 million at the study site, and approximately $5.6 billion statewide. Findings of the simulation evaluation revealed that the CV technology improved performance of intersections operating at a Level of Service (LOS) B or better, compared to lower operating levels. Operational performance improved at intersections operating at a LOS C with a 30% to 60% CV penetration rate.