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Driving a vehicle is considered a demanding task in a complex dynamic environment. For instance, driving a vehicle on urban roads, where motorized vehicles meet vulnerable road users (VRUs) creates a multifaceted environment with difficult trade-offs and interactions. Additionally, in-vehicle technology developments are being introduced to ease drivers with the driving task. However, these developments are changing “traditional” driving increasing drivers’ response in terms of information processing, thus making the driving task more demanding in some respects. Therefore, the aim of the present research is to further investigate drivers’ speed choice under varying traffic management regulations and in-vehicle warning systems. / <p>QC 20131114</p> / New Speed Limits in Built-Up Areas / COOPERS

Since the introduction of motor vehicles, the number of fatalities and accidents has been a concern for society.The number of fatalities on roads is amongst the most common causes of mortality worldwide (WHO, 2015).Even in industrialized countries the number of fatalities remains unacceptable. Therefore, in the last decades, anumber of approaches have emerged to support and boost traffic safety towards a system free from fatalities andserious impairment outcomes. ‘Sustainable Safety’ and ‘Vision Zero’ are well-known examples aiming to avoidfatalities within the traffic system and reduce injury severity when a traffic accident is inevitable. However, thenumber of fatalities and seriously injured accidents are still relatively high. More specifically, vulnerable roadusers remain involved in fatal and serious accidents even in industrialized countries. Therefore, further advancesin traffic safety studies are needed. This thesis aims at evaluating the impact of road characteristics, traffic rulesand information provision towards a safer traffic system. The thesis is composed of five scientific papers whichsummarizes the main contributions of this work. / <p>QC 20161109</p>

Les réseaux véhiculaires, connus sous le terme VANETs, sont des réseaux impliquant des communications entre deux ou plusieurs véhicules et éventuellement une communication avec des éléments d’infrastructure sur la route. Récemment, le concept de systèmes de transport intelligents (STI) a connu beaucoup d’intérêt. Les STI sont des systèmes utilisant les nouvelles technologies de communication sans fil appliquées au domaine du transport pour améliorer la sécurité routière, la logistique et les services d’information. Des défis majeurs ont besoin cependant d'être abordés pour offrir une communication sur la route sécurisée et fiable dans des environnements anonymes et quelquefois hostiles à la communication. Comme dans tout système de communication, les réseaux véhiculaires doivent opérer en respectant des contraintes en termes de qualité de service. Ces contraintes sont d’autant plus strictes quand il s’agit de fournir des services de sécurité sur la route. Ce projet vise à développer des techniques de communication véhiculaires pour le transfert des informations de manière fiable entre véhicules roulant à grande vitesse tout en contrôlant la surcharge du réseau. Ces techniques visent la prise en compte des contraintes temporelles sur les délais de transfert afin d’envisager leur utilisation dans des applications critiques telle que la sécurité sur la route. Pour ce faire, cette thèse propose d’abord un protocole optimal de dissémination de messages d’urgence pour les VANETs. Il est basé sur une stratégie de diffusion qui exploite les véhicules sur la direction opposée afin d’accélérer la dissémination du message d’urgence tout en réduisant le nombre de transmissions. Ainsi, et dans le but d’assurer une dissémination fiable et à faible surcoût, une technique de retransmission périodique intelligente permettant l’adaptation du protocol proposé à différentes densités du trafic routier est proposée. Dans un second volet, ce projet propose une approche hybride de dissémination de messages d’urgence qui combine alternativement les avantages des deux principales approches de dissémination existantes (Sender-oriented et Receiver-oriented dont notre première proposition fait partie) afin de garantir une transmission fiable des alertes tout en réduisant les délais. Les approches Receiver-Oriented qui sont les plus adaptées pour les applications de sécurité dans les VANETs peuvent minimiser la latence et les limitations des approches Sender-Oriented. Mais, ilsdoivent aussi mieux exploiter les apports des messages hello (beacons) échangés dans la technologie IEEE802.11P. Ainsi, et dans le but de surmonter les limites des approches de retransmissions périodiques et celles de relais- multiples afin d’assurer des échanges fiables de messages de sécurité tout en réduisant la surcharge de la bande passante, nous introduisons un nouveau mécanisme DR/BDR (Designated Relay/Backup Designated Relay). Le BDR, dans ce mécanisme, doit remplacer le DR et assurer sa tâche quand il détecte, à travers les beacons colorés échangés,l’échec de ce dernier dans la dissémination du message d’urgence. / Vehicular Ad hoc NETworks (VANETs) have gained considerable attention in the past few years due to their promising applications such as safety warning, transport efficiency or mobile infotainment. Avoiding accidents and traffic jams are two main immediate benefits of vehicular networks. For instance, most drivers would like to receive real-time alerts about accidents happening at a short distance in front of their vehicles since these accidents could lead to collision chains involving tens of vehicles. Also, the ability to receive an alert about a potential traffic jam would allow drivers to take alternate routes, saving both time and fuel. In both cases, warning messages should be broadcasted to all vehicles traveling over a geographical area, and need to be delivered with high reliability, low delay and low overhead. It is therefore important to develop a reliable and efficient safety information dissemination protocol in vehicular networks. Due to the vehicle mobility and lossy wireless channel, highly reliable, scalable and fast multi-hop broadcast protocol is very challenging to design. A number of solutions have been proposed in the past few years. However, the tradeoff between reliability and efficiency in such solutions needs to be carefully considered. This thesis presents an optimal protocol for the broadcast of safety messages in VANETs. Optimality, in terms of delay and transmission count, is achieved using a broadcast strategy that exploits opposite vehicles. To carry out reliable and efficient broadcast coordination, intelligent periodic rebroadcasts, which effectively adapt our protocol to sparse and dense networks, are proposed. Simulations are conducted and results are presented to show that it has a better performance over existing competing protocols. As a second contribution, we propose an alternative Receiver-Sender approach that combines advantages of the two existing dissemination approaches (Sender-oriented and Receiver-oriented to which our first proposal belongs) to ensure low latency and high reliability. The proposal can use any sender or receiver oriented protocol but the same selected one is used during all the dissemination process. In order to overcome the unreliability and broadcast overhead generated by periodic rebroadcasts and multiple relays schemes, we introduce a DR/BDR (Designated Relay/Backup Designated Relay) mechanism where the BDR has to replace the DR when detecting,from exchanged colored beacons, its failure in informing concerned vehicles.