Dissertations / Theses: 'TRAFIC CONDITIONS'

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Clairais, Aurélien. "Calage en ligne d'un modèle dynamique de trafic routier pour l'estimation en temps réel des conditions de circulation." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSET004/document.

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Les modèles de trafic ont une importance capitale pour la compréhension et la prévision des phénomènes liés aux conditions de circulation. Ils représentent une aide précieuse à tous les niveaux de gestion du trafic. Cette thèse s'attache aux problématiques liées à la gestion du trafic au quotidien. Pour les gestionnaires de réseaux, quatre enjeux sont traités. L'enjeu de rapidité renvoie au choix de l'échelle de représentation et la formulation du modèle d'écoulement. Le modèle retenu est le modèle LWR lagrangien-spatial. La fiabilité est un enjeu relatif à la prise en compte des erreurs de modèles dans les estimations des conditions de circulation. La réactivité est décrite comme la capacité de la méthode à prendre en compte en temps réel les états de trafic captés. Enfin, l'adaptabilité renvoie à la capacité des paramètres de la méthode à évoluer en tenant compte des situations de trafic observées. Les verrous scientifiques que les travaux présentés cherchent à lever s'articulent autour des quatre enjeux décrits précédemment. L'intégration de la propagation des incertitudes directement dans le modèle d'écoulement représente un premier verrou. Ensuite, la production d'indicateurs opérationnels rendant compte de la fiabilité des résultats. Concernant l'enjeu de réactivité, les verrous scientifiques traités sont la mise en place d'un schéma d'assimilation de données séquentiel et le calage des conditions internes du modèle d'écoulement intégrant les erreurs de modèle et d'observation. Enfin, concernant l'enjeu de réactivité, le verrou scientifique associé est le calage en ligne des paramètres du modèle d'écoulement. Un modèle de suivi d'erreur où les variables du modèle d'écoulement sont distribuées selon des mélanges de gaussienne est développé. Le suivi des erreurs dans le modèle est réalisé grâce à une méthode de perturbation adaptée à la formulation multi-composantes des mélanges de gaussiennes. Une analyse de sensibilité est menée afin d'établir le lien entre la robustesse de la méthode proposée et la discrétisation du réseau, le nombre de composantes dans le mélange de gaussiennes et les erreurs sur les paramètres du modèle d'écoulement. Ce modèle permet la production d'indicateurs opérationnels et leurs erreurs associées rendant compte de la fiabilité des conditions de circulation ainsi estimées. Le processus d'assimilation séquentielle permet d'estimer et de prévoir les conditions de trafic en accord avec les observations en cas de demande et d'offre non calées. L'état a posteriori est calculé à l'aide d'une formulation bayésienne connaissant les états a priori et les observations. Deux méthodes de mise à jour du modèle ont été testées. Devant les incohérences du modèle, introduites par la méthode de substitution des états a priori par les états a posteriori, la mise à jour agit aussi sur les véhicules via l'ajout, la suppression, l'avancement ou le retardement de leurs temps de passage. La validation des concepts étudiés est réalisée sur un réseau composé d'un simple lien homogène sans discontinuité. Lorsque les paramètres de l'écoulement du trafic ne sont pas calés, l'assimilation de données seule ne permet pas de propager correctement les états de trafic en accord avec la situation observée. Le calage des paramètres d'écoulement est traité dans un chapitre d'ouverture dans lequel des pistes de recherche sont suggérées afin de proposer des solutions à ce dernier verrou scientifique. Les travaux de cette thèse ouvrent la voie à des perspectives de recherche et opérationnelles. En effet, il est intéressant de quantifier le renforcement apporté par les méthodes modèle-centrées aux méthodes données-centrées usuelles dans l'estimation en temps réel et la prévision à court-terme des conditions de circulation. De plus, les méthodes développées, associées aux pistes de recherche évoquées, pourraient représenter un apport considérable aux outils d'aide à la gestion du trafic au quotidien
Traffic models are of paramount importance for understanding and forecasting traffic dynamics. They represent a significant support for all the stages of traffic management. This thesis focuses on issues related to daily traffic management. For road network managers, four challenges are addressed. The speed refers to the choice of the scale of representation and formulation of the flow model. The selected model is the Lagrangian-Space LWR model. The reliability is associated to the integration of the model errors in the traffic conditions estimation process. The reactivity is described as the capacity of the method to take into account the prevailling traffic states in real time. Finally, the versatility refers to the capacity of the method parameters to evolve considering the observed traffic situations.The scientific challenges that the presented works aim are based on the four issues. The integration of the uncertainties into the flow model is a first challenge. Then, the production of operational indicators that account for the reliability of the results is discussed. Concerning the reactivity, the addressed scientific challenges are the establishment of a vehicle indexes based sequential data assimilation process and the calibration of the model's internal conditions. Finally, concerning the versatility, the associated scientific question is the online calibration of the parameters of the traffic flow model. A model for tracking the errors,assumed to be distributed following Gaussian mixtures, is developped. The error tracking is achieved thanks to an original perturbation method designed for multi-modal Gaussian mixtures. A sensitivity analysis is performed in order to establish a link between the designed method's robustness and the discretization of the network, the number of modes in the Gaussian mixture and the errors on the flow model's parameters. The data assimilation process enables to propagate traffic conditions in accordance with the observed situation in case of non-calibrated demand and supply. The posterior state is calculated by means of a Bayesian inference formulation knowing the prior and observed states. Two methods for model update have been tested. Facing model inconsistencies introduced by the method of substituting \textit{prior} states by \textit{posterior} states, the update acts also on the vehicles by means of addition, deletion, advancing and delaying of the passing times. The validation of the proposed solutions is achieved on a network composed of a simple homogeneous link without discontinuity. When the parameters of the traffic flow models are not calibrated, the data assimilation alone is not able to propagate the traffic states in accordance with the observed situation. The calibration of the parameters is addressed in an opening chapter in which several research avenues are proposed to resolve this last scientific question. The works in this thesis pave the way to perspectives in both research and operational domains. Indeed, it is interesting to quantify the reinforcement brought by model centered methods to usual data centered methods for the real time estimation and the short term forecasting of traffic conditions. Furthermore, the developed methods, associated to the cited research avenues, may represent a significant intake in the daily traffic management tools

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Lecocq, Patrick. "Contribution à l'étude du fonctionnement de balises de localisation de véhicules ferroviaires dans des conditions climatiques défavorables." Lille 1, 1992. http://www.theses.fr/1992LIL10103.

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Dans les transports guidés futurs (par exemple le système ASTREE de la SNCF) la localisation des trains se fera au moyen de balises transpondeuses passives placées le long de la voie. Ces balises indiquent au mobile sa position lorsqu'il passe au-dessus. La transmission de cette information s'effectue par un canal radioélectrique et le bilan de liaison est facilement prévisible lorsque les conditions climatiques sont bonnes. Par contre lorsqu'elles sont défavorables, par exemple en présence d'eau ou de neige, il est indispensable de prévoir les fluctuations ou les disfonctionnements que pourrait subir le système. Dans la première partie de notre travail nous rappelons quelques exemples de balises de localisation et présentons la balise du Laboratoire. Dans la seconde partie de notre mémoire, nous nous sommes attachés à calculer et à vérifier expérimentalement le bilan de liaison dans une large bande de fréquence (100 MHz―10 GHz) et dans divers cas de conditions climatiques défavorables. Dans la dernière partie nous proposons un moyen d'améliorer les performances de ces dispositifs en cas de conditions climatiques défavorables

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Vatan, Şahika. "Development of a legibility model and PC software to predict the legibility of text on trafic [sic] traffic signs for high luminance and contrast conditions." Ohio : Ohio University, 2003. http://www.ohiolink.edu/etd/view.cgi?ohiou1175712386.

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Hatchi, Roméo. "Analyse mathématique de modèles de trafic routier congestionné." Thesis, Paris 9, 2015. http://www.theses.fr/2015PA090048/document.

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Cette thèse est dédiée à l'étude mathématique de quelques modèles de trafic routier congestionné. La notion essentielle est l'équilibre de Wardrop. Elle poursuit des travaux de Carlier et Santambrogio avec des coauteurs. Baillon et Carlier ont étudié le cas de grilles cartésiennes dans $\RR^2$ de plus en plus denses, dans le cadre de la théorie de $\Gamma$-convergence. Trouver l'équilibre de Wardrop revient à résoudre des problèmes de minimisation convexe. Dans le chapitre 2, nous regardons ce qui se passe dans le cas de réseaux généraux, de plus en plus denses, dans $\RR^d$. Des difficultés nouvelles surgissent par rapport au cas initial de réseaux cartésiens et pour les contourner, nous introduisons la notion de courbes généralisées. Des hypothèses structurelles sur ces suites de réseaux discrets sont nécessaires pour s'assurer de la convergence. Cela fait alors apparaître des fonctions qui sont des sortes de distances de Finsler et qui rendent compte de l'anisotropie du réseau. Nous obtenons ainsi des résultats similaires à ceux du cas cartésien. Dans le chapitre 3, nous étudions le modèle continu et en particulier, les problèmes limites. Nous trouvons alors des conditions d'optimalité à travers une formulation duale qui peut être interprétée en termes d'équilibres continus de Wardrop. Cependant, nous travaillons avec des courbes généralisées et nous ne pouvons pas appliquer directement le théorème de Prokhorov, comme cela a été le cas dans \cite{baillon2012discrete, carlier2008optimal}. Pour pouvoir néanmoins l'utiliser, nous considérons une version relaxée du problème limite, avec des mesures d'Young. Dans le chapitre 4, nous nous concentrons sur le cas de long terme, c'est-à-dire, nous fixons uniquement les distributions d'offre et de demande. Comme montré dans \cite{brasco2013congested}, le problème de l'équilibre de Wardrop est équivalent à un problème à la Beckmann et il se réduit à résoudre une EDP elliptique, anisotropique et dégénérée. Nous utilisons la méthode de résolution numérique de Lagrangien augmenté présentée dans \cite{benamou2013augmented} pour proposer des exemples de simulation. Enfin, le chapitre 5 a pour objet l'étude de problèmes de Monge avec comme coût une distance de Finsler. Cela se reformule en des problèmes de flux minimal et une discrétisation de ces problèmes mène à un problème de point-selle. Nous le résolvons alors numériquement, encore grâce à un algorithme de Lagrangien augmenté
This thesis is devoted to the mathematical analysis of some models of congested road traffic. The essential notion is the Wardrop equilibrium. It continues Carlier and Santambrogio's works with coauthors. With Baillon they studied the case of two-dimensional cartesian networks that become very dense in the framework of $\Gamma$-convergence theory. Finding Wardrop equilibria is equivalent to solve convex minimisation problems.In Chapter 2 we look at what happens in the case of general networks, increasingly dense. New difficulties appear with respect to the original case of cartesian networks. To deal with these difficulties we introduce the concept of generalized curves. Structural assumptions on these sequences of discrete networks are necessary to obtain convergence. Sorts of Finsler distance are used and keep track of anisotropy of the network. We then have similar results to those in the cartesian case.In Chapter 3 we study the continuous model and in particular the limit problems. Then we find optimality conditions through a duale formulation that can be interpreted in terms of continuous Wardrop equilibria. However we work with generalized curves and we cannot directly apply Prokhorov's theorem, as in \cite{baillon2012discrete, carlier2008optimal}. To use it we consider a relaxed version of the limit problem with Young's measures. In Chapter 4 we focus on the long-term case, that is, we fix only the distributions of supply and demand. As shown in \cite{brasco2013congested} the problem of Wardrop equilibria can be reformulated in a problem à la Beckmann and reduced to solve an elliptic anisotropic and degenerated PDE. We use the augmented Lagrangian scheme presented in \cite{benamou2013augmented} to show a few numerical simulation examples. Finally Chapter 5 is devoted to studying Monge problems with as cost a Finsler distance. It leads to minimal flow problems. Discretization of these problems is equivalent to a saddle-point problem. We then solve it numerically again by an augmented Lagrangian algorithm

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Benferhat, Sabri. "Simulation des conditions de trafic intracellulaire d'un réseau sans fil en milieu industriel par un modèle de propagation composite." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2009. http://tel.archives-ouvertes.fr/tel-00725659.

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Cette thèse traite de l'utilisation des réseaux locaux sans fil dans un environnement industriel. Nous traitons l'impact des conditions de propagation et leur implémentation, sur des outils de simulations. La première partie s'intéresse au choix du modèle par des méthodes analytiques appliquées sur des mesures. La comparaison des performances obtenues dans un site avec les résultats de simulations montre une nette différence. Elle nous a permis de conclure que les modèles classiques ne permettent pas de simulations pertinentes pour un tel contexte. Pour ces raisons, nous proposons une nouvelle façon de modéliser les conditions de propagation. Notre modèle appelé "split model" permet de distinguer : liens entre stations et point d'accès des liens entre stations. Nous avons utilisé le modèle dans la simulation pour étudier les performances dans une cellule en mode infrastructure de la norme 802.11. Les résultats montrent que des collisions au niveau du point d'accès sont constatées et en résulte une dégradation des performances pour laquelle les mécanismes prévus pour compenser l'effet du terminal caché (RTS/CTS) se sont montrés inefficaces. L'utilisation du split model dans un processus de simulation met en avant les effets dus a l'existence de ces zones cachées et permet d'avoir des résultats obtenus par simulation plus représentatifs du comportement d'une cellule recouvrant une chaîne de production.

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Fahs, Walid. "Simulation des conditions de trafic intracellulaire d'un réseau sans fil en milieu industriel par un modèle de propagation composite." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00731049.

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Ce travail a pour contexte des applications industrielles pour lesquelles des mobiles communiquent pour coopérer via un réseau local sans fil. La première étape a consisté à trouver le modèle de propagation le mieux adapté à une application industrielle générique que nous avons choisie. La deuxième étape a eu pour but de minimiser le temps nécessaire pour que l'ensemble des mobiles sous une même cellule d'un réseau 802.11b, puisse échanger les informations partagées dans le cadre de leur(s) coopération(s). La sélection d'un modèle de propagation pertinent pour le site industriel choisi est basée sur une campagne de mesures. L'ajustement des paramètres des différents modèles exixtants a permis de retenir celui préconisé par l'ITU sous la référence Pr-1238 pour remplacer les modèles de base, non pertinents, proposés par l'outil de simulation NS2. L'optimisation de la longueur du cycle des échanges entre mobiles a été réalisée selon deux axes : premièrement en agissant sur les façons de diffuser des informations à un groupe de mobiles sans être tributaire de l'envoi des beacons par le point d'accès, deuxièmement en modifiant l'aspect exponentiel binaire de l'algorithme de Backoff pour réduire le temps d'accès au médium radio. Des simulations faites à partir de l'outil NS2 ont permis de montrer qu'une diffusion par classe (broadcast) réalisée par une émulation de la méthode PCF (couplée à un mécanisme de cache dans le point d'accès) donnait de meilleurs résultats que la méthode Multiple-Unicast quand le nombre de mobiles augmente. Dans le contexte de cette étude, la modification de l'évolution de la fenêtre de tirage au sort du Backoff apporte une amélioration du temps de transit des informations par rapport au BEB de la norme 802.11.

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Merbouh, M’hammed. "Contribution à la modélisation du comportement rhéologique des enrobés bitumineux : influence des conditions extrêmes de température et de trafic en fatigue." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14214/document.

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Les particularités de climat et les nouveaux avions très gros porteurs, imposent des effets cycliques dangereux sur les couches de roulement. Les simulations en laboratoire de ces phénomènes ont montrées leur influence sur les qualités viscoélastiques du bitume et enrobé, qui sont fonctions des variations de la température. Telles que les déformations permanentes avec perte de résistance et le durcissement du bitume associé au vieillissement accéléré. Les lois de comportement en fatigue sous trafic prouvent que les grandes amplitudes de déformation en tandem endommagent sévèrement l’enrobé. Les informations recueillies permettent de mieux prévoir l’évolution du comportement in situ du bitume et enrobé
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Choub-Faha, Christophe Péguy. "Emploi régional et trafic aérien de passagers au Canada : une analyse de causalité." Master's thesis, Université Laval, 2012. http://hdl.handle.net/20.500.11794/23953.

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Les infrastructures de transport sont d’importants catalyseurs de développement régional. Réciproquement, la croissance économique favorise le développement des infrastructures de transport. Quel est le lien qui existe entre l’activité aéroportuaire de passagers (nombre de passagers embarqués/débarqués) et le développement économique régional (volume de l’emploi total) ? Ce travail de recherche examine cette relation en se concentrant sur les notions de causalité instantanée et ‘de Granger’. Nous utilisons des données annuelles couvrant la période 1988-2009 sur les quinze régions métropolitaines qui hébergent les principaux aéroports canadiens. Nos résultats concluent à l’existence des deux formes de causalité pour le Canada dans son ensemble, le Canada Central et le Canada Atlantique, que ce soit avec les variables en niveau ou en taux de croissance. Aucune relation causale n’est détectée dans les régions du Canada Pacifique et les Prairies. Lorsque l’analyse s’effectue au niveau des principaux aéroports canadiens, de nombreuses relations de causalité de Granger émergent, mettant ainsi en évidence l’étroite imbrication entre la dynamique locale de l’emploi et l’activité aéroportuaire de passagers, que ce soit pour les grands pôles économiques (Ottawa, Toronto et Montréal) ou les régions plus périphériques (notamment Régina, Saskatoon et Halifax).

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Delisle, Pascal. "Colonisation agricole et développement soutenable en forêt tropicale : pour une approche multidimensionnelle, le cas de l'Amazonie colombienne." Paris 1, 1998. http://www.theses.fr/1998PA010055.

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Après avoir representé dans l'après-guerre, par action ou omission publique, une valve d'échappement de la pression sociale et démographique andine, l'Amazonie colombienne est entrée en crise dans les années 1970. Sous la pression d'une logique economique inegalitaire et de relations sociales souvent tendues voire violentes, l'echec économique de la colonisation agricole s'est affirmé, ouvrant la voie à une concentration progressive des terres destinées à l'élevage bovin et facilitant l'émergence des cultures illicites. Comme à l'intérieur du pays, les mouvements de guerilla se sont developpés à la faveur de cette différenciation sociale conflictuelle ; ils se sont alors consolidés en se greffant sur l'économie de la drogue. Cette thèse entend analyser l'insoutenabilité du développement de l'Amazonie colombienne à la lumière d'une approche multidimensionnelle qui prenne en compte la coévolution des sphères écologique, économique et sociopolitique. Les seuls outils de l'analyse économique traditionnelle, pas plus que l'analyse néoclassique de l'environnement ne peuvent en effet permettre une compréhension des mécanismes à l'oeuvre et seule une démarche multidimensionnelle, englobant les dimensions économiques et écologiques dans la sphère plus large du processus politique et des réalités sociales est à même de fournir une grille de lecture pertinente et de proposer des remèdes efficaces. La démarche se développe en trois temps : - comprendre tout d'abord les ressorts historiques et sociaux de la colonisation agricole amazonienne et stigmatiser son échec multidimensionnel. - évaluer ensuite le discours des principales agences en charge du développement, leur capacité à rendre compte de la dynamique colonisatrice et à ouvrir la voie d'un développement soutenable. - proposer enfin une démarche alternative pour le développement amazonien qui traite simultanement les déséquilibres sociopolitiques et économiques régionaux, et qui fasse de la reconstruction d'une gouvernabilité locale autour d'un projet multidimensionnel, celui de réserve paysanne, le moyen de sortir du cercle vicieux actuel
In the south of Colombia, the Amazonian rainforest has been suffering a process of agricultural colonisation for the last forty years. Along with a more usual process of rural exodus, the interior colonisation has represented an outlet for the demographic and social pressure of the andean rural areas. The economic failure of small peasants' colonisation has given birth to a process of land concentration accompanied by social conflicts and cattle ranching. Since the end of the 1970's, this economic failure and socio-political situation have opened the way to a powerful illegal economy based on the coca culture. In reaction to social inequality, the guerrilla movements have emerged and quickly got involved in the illegal economy. This thesis proposes to analyse the unsustainability of the colombian amazonian development on a multidimensional basis, taking into account the coevolution of the ecological, economic and socio-political dimensions. As neither the usual tools of conventional economics nor the environmental economics analysis seem capable to explain the current dynamics and propose effective alternative solutions, a multidimensional approach seems to be needed. The argumentation is made in three steps: - the first one consists in understanding the historical and social causes of the amazonian colonisation and expose its multidimensional failure. - the second step consists in evaluating the capacity of the main international agencies'analysis and proposals to deal with the deforestation problem. - At last, the thesis proposes an alternative approach for the amazonian development that deals simultaneously with the socio-political and economic aspects of the current situation. A way towards sustainability is proposed via the reconstruction of the local and regional governance on the basis of a multidimensional project, already accepted by the legislator : the peasants' reserve

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Vu, Thuong Van. "Application du codage réseau dans l'environnement sans fil : conditions de codage et contrôle de redondance adaptatif." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2014. http://tel.archives-ouvertes.fr/tel-01022166.

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Depuis 2001, le codage réseau a devenu une technique de communication qui permet des meilleures performances réseaux. Au lieu de relayer les paquets séparément, le codage réseau permet aux noeuds réseaux de combiner plusieurs paquets natifs en un seul paquet codé. Le réseau peut réduire le nombre de transmissions, réduire le temps de transfert et augmenter le débit de transmission. Le codage réseau ne suit pas l'hypothèse dans laquelle l'information reste séparée et invariable dans chaque paquet de la source à la destination. Dans le codage réseau, les informations transportées dans les paquets ne doivent pas être endommagées mais elles peuvent être mixées et transformées. Dans le contexte de cette thèse, nous contribuons dans deux directions: l'augmentation de la capacité du réseau et la fiabilité de la transmission contre les erreurs aléatoires. Pour augmenter la capacité du réseau, nous avons défini des nouvelles conditions de codage dans le codage réseau inter-flux. Pour fournir la fiabilité de la transmission, nous avons proposé de nouveaux protocoles de codage réseau. Les résultats de simulations via NS-2 ont montré les améliorations importantes des performances.

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Achit, Hamza. "Analyse économique des préjudices et des indemnisations des accidents de la circulation routière : une approche par la victime." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC0049.

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Cette thèse analyse les répercussions économiques des accidents de la route sur les victimes blessées. Nous étudions les conséquences en termes de dépenses de santé et en termes d’arrêt de travail. Les analyses s’appuient sur une base de données originale issue d’une procédure d’extraction spécifique du système d’information de l’Assurance Maladie. Ce système d’information constitue une base de données quasi exhaustive des victimes des accidents de la route.Différentes analyses descriptives et économétriques sont menées. Dans un premier temps, nous utilisons des modèles d’équations estimantes généralisées pour analyser les déterminants du préjudice en termes de dépenses de santé, et des modèles de survie pour l’analyse des déterminants du préjudice lié à un épisode d’arrêt de travail. Dans un deuxième temps, nous analysons l’évolution de ces préjudices dans le temps, au moyen de la méthode dite des trajectoires de développement (Group-Based Trajectory). Cette méthode nous a permis aussi d’établir une typologie des victimes blessées sur la base de la similitude des devenirs à long terme. Enfin, pour éclairer l'opinion et les décideurs sur les coûts occasionnés aux différents types de victimes d’accident nous évaluons l'effet causal moyen d’un accident avec la méthode de l’appariement exact
This thesis analyzes the economic consequences of road accidents for the injured victims. We study the impacts in terms of health spending and in terms of sick leave. The analyses rely on an original dataset obtained by a specific extraction from the information system of the French Health Insurance. This information system constitutes an almost exhaustive database of victimsof road accidents.Different descriptive and econometric analyses are conducted. First, we use generalized estimating equations models to analyze the determinants of extra health expenses, and survival models for the analysis of the determinants of economic loss related to a sick leave episode. Secondly, we analyze the evolution of these extra expenses and losses over time by means of agroup-based trajectory model. This method also allowed us to establish a typology of injured victims based on the similarity of long-run outcomes. Finally, to inform the public and decision makers on the costs occasioned for the different types of accident victims we evaluate the averagecausal effect of an accident with the exact matching method

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Gille, Laure-Anne. "Caractérisation physique et perceptive de différentes compositions de trafic routier urbain pour la détermination d'indicateurs de gêne en situation de mono-exposition et de multi-exposition." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSET005/document.

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Le bruit de la circulation routière, et en particulier le bruit des deux-roues motorisés, constituent une importante source de gêne sonore. Afin d’estimer l’exposition sonore dans les villes de plus 100 000 habitants, la directive européenne 2002/49/CE impose la réalisation de cartes de bruit stratégiques, basées sur l’indice Lden. Cet indice est également utilisé dans des relations exposition-réponse, afin de prédire les pourcentages de personnes gênées, notamment par le bruit du trafic routier. En couplant les cartes de bruit stratégiques et ces relations exposition-réponse, des cartes de gêne pourraient être établies. Toutefois, la pertinence de cet indice pour prédire la gêne due au bruit en milieu urbain est souvent remise en cause, car de nombreux facteurs acoustiques influents (e.g. les caractéristiques spectrales et temporelles) ne sont pas pris en compte par cet indice. Cette thèse vise à améliorer la caractérisation de la gêne due au bruit de trafic routier urbain en considérant différentes compositions de trafic et la présence des deux-roues motorisés. Dans ce but, des expériences sont menées en conditions contrôlées. Une première étude a porté sur l’influence de plusieurs facteurs acoustiques relatifs aux périodes de calme et aux bruits de passage de véhicules sur la gêne due au bruit de trafic routier urbain. Cette étude a conclu à l’influence de la présence de périodes de calme et du nombre de véhicules au sein du trafic routier urbain et à l’absence d’influence de l’ordre des véhicules routiers, de la position et de la durée des périodes de calme. Ces résultats ont été utilisés afin de mener la caractérisation physique et perceptive de différentes compositions de trafic routier urbain. La régression multi-niveau a été utilisée pour calculer la gêne, en considérant 1) des facteurs acoustiques influents à l’aide de combinaisons pertinentes d’indices et 2) un facteur non acoustique : la sensibilité au bruit. Dans les villes, le bruit routier est souvent entendu en situation de multi-exposition avec d’autres bruits. Dans le cadre de ces travaux de thèse, les situations de multi-exposition aux bruits routier et d’avion ont été étudiées. Pour cela, un travail semblable à celui mené pour le bruit de trafic routier urbain a été mené pour le bruit d’avion conduisant également à des combinaisons pertinentes d’indices. En vue de caractériser les gênes dues aux bruits de trafic routier et d’avion pour des situations de multi-exposition sonore, les données des précédentes expériences ainsi que celles d’une expérience conduite en situation de multi-exposition à ces bruits combinés ont été utilisées au travers d’une régression multi-niveau adaptée, comme cela a pu être mené dans la littérature. La régression multi-niveau a ainsi permis la proposition de modèles de gêne pour chaque source de bruit. Puis, la gêne totale due à des situations de multi-exposition à ces bruits a été étudiée, afin de mettre en évidence les phénomènes perceptifs mis en jeu. Des modèles de gêne totale ont été proposés, en utilisant les modèles de gêne due à chaque source. Enfin, les modèles de gêne obtenus pour chaque source et les modèles de gêne totale ont été confrontés aux données d’une enquête socio-acoustique. A cet effet, une méthodologie a été proposée afin d’estimer les différents indices des modèles à partir des valeurs du Lden, issues de cartes de bruit et utilisées pour définir l’exposition au bruit des personnes enquêtées. Cette confrontation a montré que les modèles proposés à partir d’expériences menées en laboratoire et couplés à la méthodologie d’estimation des indices à partir des valeurs du Lden permettent une bonne prédiction de la gêne in situ
Road traffic noise, and in particular powered two-wheeler noise, constitute an important source of noise annoyance. In order to estimate the noise exposure in cities of more than 100 000 inhabitants, the European directive 2002/49/EC requires the elaboration of strategic noise maps, based on the Lden index. This index is also used in exposureresponse relationships, to predict the percentages of annoyed people, by road traffic noise for example. By coupling strategic noise maps and these exposure-response relationships, noise annoyance maps could be established. The relevance of this index to predict noise annoyance in cities is however often questioned, since many influential acoustical factors (e.g. spectral and temporal features) are not considered by this index. The aim of this thesis is to enhance the characterization of noise annoyance due to different compositions of urban road traffic including powered two-wheelers. To achieve this goal, experiments were carried out under controlled conditions. A first study concerned the influence of several acoustical features related to quiet periods and vehicle pass-by noises on the annoyance due to urban road traffic noise. This study demonstrated the influence of the presence of quiet periods and of the number of vehicles within the urban road traffic and to the absence of the influence of the order of the vehicle pass-by noises, the position and duration of quiet periods. These results were used to carry out the physical and perceptual characterization of different compositions of urban road traffic noise. Multilevel regression was used to calculate noise annoyance, by coupling combinations of indices relating to influential acoustical features and an individual factor: noise sensitivity. In cities, road traffic noise is often combined with other noises. In the framework of this thesis, noise exposure to road traffic noise combined with aircraft noise was studied. Therefore, the same work as the one performed for urban road traffic noise was carried out for aircraft noise, leading also to relevant combinations of noise indices. In order to characterize annoyances due to road traffic noise and to aircraft noise in a combined exposure situation, data from the previous experiments and from an experiment dealing with these combined noises were used through an appropriate multilevel regression, as done in literature. The regression allows annoyance models for each noise source to be proposed. Then, total annoyance due to combined noises was studied, in order to highlight the perceptual phenomena related to the combined exposure. Total noise annoyance models were proposed, using proposed annoyance model of each noise source. Finally, these single source annoyance models and total annoyance models were tested using data of a socio-acoustic survey. To do this, a methodology has been proposed to estimate the different indices involved in the annoyance models, from the Lden values obtained from the strategic noise maps and used to define the noise exposure of the respondents. This confrontation showed that the models proposed on the basis of experiments carried out under laboratory conditions and coupled with a methodology of estimation of the noise indices from Lden values, enabled a good prediction of in situ annoyance

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Yulianto, Budi. "Application of fuzzy logic to traffic signal control under mixed traffic conditions." Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440572.

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Acharya, Abhishek. "Modeling of oversaturated conditions on arterial networks." Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008m/acharya.pdf.

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Gopalan, Ganesh. "Improvement of traffic flow conditions using access management techniques : a netsim study /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1426063.

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Shaik, Nawaz M. "Improving traffic flow conditions for interstate work-zones evaluation of three traffic control devices /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4260.

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Thesis (M.S.)--University of Missouri-Columbia, 2005.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 11, 2006) Includes bibliographical references.

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Molander, Rikard. "Stability conditions for scheduled waiting time in railway traffic." Thesis, Uppsala universitet, Matematisk statistik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-198812.

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Wang, Shi S. M. Massachusetts Institute of Technology. "Real time toll optimization based on predicted traffic conditions." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104321.

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Thesis: S.M. in Transportation, Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 93-98).
Road pricing is an effective method of demand management. Pricing on highway managed lanes is usually implemented as time-of-day or dynamic tolling in practice. Toll rates are usually updated according to latest traffic measurement and based on pre-defined rules. Researches on highway pricing can be generally categorized as analytical, reactive or optimization-based approaches. The limitations of current studies are compared and discussed in this thesis. A new framework is proposed which aims to develop an adaptive integrated simulation-optimization framework that brings together several enhancements: real time, predictive, simulation-based and consistent. The main components of the framework include DTA model, DynaMIT, for evaluating control strategies, optimization module solving for optimal solution and real-life traffic system providing surveillance data. Optimization problem is formulated with rolling horizon scheme, and presented with basic models for revenue maximization. Close-loop testing approach is proposed by replacing traffic system with a microscopic simulator, MITSIM. Tests are first conducted on a two-path synthetic network to demonstrate the capability of the framework with changing demand and different behavior parameters. Then a case study is performed on NTE Express Lanes network in Texas. Calibration of the network with multiple sources of traffic data is discussed, and initial calibration results with sensor data are presented. Also, the models are extended to account for the regulation rules imposed by the local government. Optimization results for morning peak period on a typical weekday are presented, and the resulting revenue is compared with the benchmark case. Finally, potential improvement in solution algorithm is discussed for the system's real time computational requirements. The main contribution of the thesis includes: 1) identifying the limitations of tolling strategies in practice and in academic researches, 2) proposing an adaptive integrated simulation-optimization framework, 3) demonstrating the capability of the framework through close-loop testing on a synthetic network, and 4) applying the framework on a real-world network with managed lanes, and proposing calibration approach incorporating multi-source traffic data.
by Shi Wang.
S.M. in Transportation

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Guo, Fangce. "Short-term traffic prediction under normal and abnormal conditions." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/23661.

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Intelligent Transport Systems (ITS) is a field that has developed rapidly over the last two decades, driven by the growing need for better transport network management strategies and by continuing improvements in computing power. However, a number of ITS applications, such as Advanced Traveller Information Systems (ATIS), Dynamic Route Guidance (DRG) and Urban Traffic Control (UTC) need to be proactive rather than reactive, and consequently require the prediction of traffic state variables into the short-term future. Similarly, individual travellers can use this predictive information to plan their mobility more efficiently. This PhD thesis develops models that are able to accurately predict short-term traffic variables such as link travel time and traffic flow on urban arterial roads under both normal and abnormal traffic conditions. This research first reviews the state of the art in data prediction applications in engineering domains especially traffic engineering and presents existing statistical and machine learning methods and their applications in relation to short-term traffic prediction. This review establishes that most existing work has focused on the apparent superiority of one individual statistical or machine learning method over another. Little attention has been paid, however, to the issues surrounding the overall structure of prediction models, in particular in relation to data smoothing and error feedback. In developing a short-term traffic prediction model, therefore, a 3-stage framework including a data smoothing step and an error feedback mechanism is proposed. This proposed framework is applied in conjunction with five different machine learning methods to develop a range of short-term traffic prediction methods. The proposed prediction framework is then tested under different traffic conditions using traffic data generated from a traffic simulation model of a corridor in Southampton. The prediction results show that the proposed 3-stage prediction framework can improve the accuracy of traffic prediction, regardless of the machine learning method used under both normal and abnormal traffic conditions. After demonstrating the effectiveness of predicting traffic variables using simulated data, the proposed methodology is then applied to real-world traffic data collected from different sites in London and Maidstone. These results also show that the framework can improve the accuracy of prediction regardless of the machine learning tool used. The prediction accuracy comparison shows that the proposed 3-stage prediction framework can improve the prediction accuracy for either travel time or traffic flow data under both normal and abnormal traffic conditions. In addition, the results indicate that the kNN based prediction method, when applied through the proposed framework, outperforms other selected machine learning methods under abnormal traffic conditions on urban roads. The findings suggest that, in order to arrive at a robust and accurate prediction model, attention should be paid to combining data smoothing, model structure and error feedback elements.

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Chynchenko, Yu V., I. M. Kim, O. S. Samartseva, and V. O. Vakhrina. "Experimental research of terminal control area operations under uncertainty conditions." Thesis, Proceedings of the sixth world congress “Aviation in the XXI-st century” “Safety in aviation and space technology”, 2014. http://er.nau.edu.ua/handle/NAU/16162.

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The experimental research of terminal control area operations under uncertainty conditions is considered. The Identification and assessment of threat factors in air traffic controller operation, identification of the point of controllers’ extreme operational conditions appearance and recommendations on associated errors capture and mitigation and improvement of airspace structure on the strategic planning phase are considered.

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Narh, Abraham Tetteh. "The application of chaos theory to forecast urban traffic conditions." Thesis, University of Newcastle upon Tyne, 2016. http://hdl.handle.net/10443/3189.

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This thesis explores the application of Chaos Theory to forecast urban traffic conditions. The research takes advantage of a highly resolved temporal and spatial data available from the Split Cycle Optimisation Technique (SCOOT) system, in order to overcome the limitations of previous studies to investigate applying Chaos Theory in traffic management. This thesis reports on the development of a chaos-based algorithm and presents results from its application to a SCOOT controlled region in the city of Leicester, UK. A Phase Space Reconstruction method is used to analyse non-linear data from the SCOOT system, and establishes that a 20 second resolved data is suitable for understanding the dynamics of the traffic system. The research develops the Lyapunov exponent as a chaos-based parameter to forecast link occupancy using a multiple regression model based on the temporal and spatial relationships across the links in the network. The model generates a unique forecast function for each link for every hour of the day. The study demonstrates that Lyapunov exponents can be used to predict the occupancy profile of links in the network to a reasonably high level of accuracy (R-values generally greater than 0.6). Evidence also suggests that the predictions from the Lyapunov exponents (rather than occupancy) make it possible to report on the impending conditions over a wider part of the network so that imminent congested conditions can be foreseen in advance and mitigation measures implemented. Thus, the thesis concludes that incorporating chaos-based algorithms in this way can enable urban traffic control systems to be one-step ahead of traffic congestion, rather than one-step behind. This would improve the management of traffic on a more strategic level rather than purely within smaller network regions thus playing an important role in improving journey times and air quality and making a vital contribution to mitigating climate change.

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Hassan, Hany Mohamed Ramadan. "Improving traffic safety and drivers' behavior in reduced visibility conditions." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4923.

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Moreover, two issues that have not explicitly been addressed in prior studies are; (1) the possibility of predicting VR crashes using traffic data collected from the Automatic Vehicle Identification (AVI) sensors installed on Expressways and (2) which traffic data is advantageous for predicting VR crashes; LDs or AVIs. Thus, this research attempts to examine the relationships between VR crash risk and real-time traffic data collected from LDs installed on two Freeways in Central Florida (I-4 and I-95) and from AVI sensors installed on two Expressways (SR 408 and SR 417). Also, it investigates which data is better for predicting VR crashes. The approach adopted here involves developing Bayesian matched case-control logistic regression using the historical VR crashes, LDs and AVI data. Regarding models estimated based on LDs data, the average speed observed at the nearest downstream station along with the coefficient of variation in speed observed at the nearest upstream station, all at 5-10 minute prior to the crash time, were found to have significant effect on VR crash risk. However, for the model developed based on AVI data, the coefficient of variation in speed observed at the crash segment, at 5-10 minute prior to the crash time, affected the likelihood of VR crash occurrence. Argument concerning which traffic data (LDs or AVI) is better for predicting VR crashes is also provided and discussed.; The results revealed that gender, age, road type, visibility condition, and familiarity with VSL signs were the significant factors affecting the likelihood of reducing speed following CMS/VSL instructions in reduced visibility conditions. Other objectives of this survey study were to determine the content of messages that would achieve the best perceived safety and drivers' compliance and to examine the best way to improve safety during these adverse visibility conditions. The results indicated that "Caution-fog ahead-reduce speed" was the best message and using CMS and VSL signs together was the best way to improve safety during such inclement weather situations. In addition, this research aimed to thoroughly examine drivers' responses under low visibility conditions and quantify the impacts and values of various factors found to be related to drivers' compliance and drivers' satisfaction with VSL and CMS instructions in different visibility and traffic conditions. To achieve these goals, Explanatory Factor Analysis (EFA) and Structural Equation Modeling (SEM) approaches were adopted. The results revealed that drivers' satisfaction with VSL/CMS was the most significant factor that positively affected drivers' compliance with advice or warning messages displayed on VSL/CMS signs under different fog conditions followed by driver factors. Moreover, it was found that roadway type affected drivers' compliance to VSL instructions under medium and heavy fog conditions. Furthermore, drivers' familiarity with VSL signs and driver factors were the significant factors affecting drivers' satisfaction with VSL/CMS advice under reduced visibility conditions. Based on the findings of the survey-based study, several recommendations are suggested as guidelines to improve drivers' behavior in such reduced visibility conditions by enhancing drivers' compliance with VSL/CMS instructions.; This study is concerned with the safety risk of reduced visibility on roadways. Inclement weather events such as fog/smoke (FS), heavy rain (HR), high winds, etc, do affect every road by impacting pavement conditions, vehicle performance, visibility distance, and drivers' behavior. Moreover, they affect travel demand, traffic safety, and traffic flow characteristics. Visibility in particular is critical to the task of driving and reduction in visibility due FS or other weather events such as HR is a major factor that affects safety and proper traffic operation. A real-time measurement of visibility and understanding drivers' responses, when the visibility falls below certain acceptable level, may be helpful in reducing the chances of visibility-related crashes. In this regard, one way to improve safety under reduced visibility conditions (i.e., reduce the risk of visibility related crashes) is to improve drivers' behavior under such adverse weather conditions. Therefore, one of objectives of this research was to investigate the factors affecting drivers' stated behavior in adverse visibility conditions, and examine whether drivers rely on and follow advisory or warning messages displayed on portable changeable message signs (CMS) and/or variable speed limit (VSL) signs in different visibility, traffic conditions, and on two types of roadways; freeways and two-lane roads. The data used for the analyses were obtained from a self-reported questionnaire survey carried out among 566 drivers in Central Florida, USA. Several categorical data analysis techniques such as conditional distribution, odds' ratio, and Chi-Square tests were applied. In addition, two modeling approaches; bivariate and multivariate probit models were estimated.; Underground loop detectors (LDs) are the most common freeway traffic surveillance technologies used for various intelligent transportation system (ITS) applications such as travel time estimation and crash detection. Recently, the emphasis in freeway management has been shifting towards using LDs data to develop real-time crash-risk assessment models. Numerous studies have established statistical links between freeway crash risk and traffic flow characteristics. However, there is a lack of good understanding of the relationship between traffic flow variables (i.e. speed, volume and occupancy) and crashes that occur under reduced visibility (VR crashes). Thus, another objective of this research was to explore the occurrence of reduced visibility related (VR) crashes on freeways using real-time traffic surveillance data collected from loop detectors (LDs) and radar sensors. In addition, it examines the difference between VR crashes to those occurring at clear visibility conditions (CV crashes). To achieve these objectives, Random Forests (RF) and matched case-control logistic regression model were estimated. The results indicated that traffic flow variables leading to VR crashes are slightly different from those variables leading to CV crashes. It was found that, higher occupancy observed about half a mile between the nearest upstream and downstream stations increases the risk for both VR and CV crashes. Moreover, an increase of the average speed observed on the same half a mile increases the probability of VR crash. On the other hand, high speed variation coupled with lower average speed observed on the same half a mile increase the likelihood of CV crashes.
ID: 030423512; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 193-210).
Ph.D.
Doctorate
Civil, Environmental and Construction Engineering
Engineering and Computer Science

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23

Fan, Bo. "Railway traffic rescheduling approaches to minimise delays in disturbed conditions." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3677/.

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The advent of modern railway signalling and train control technology allows the implementation of advanced real-time railway management. A number of researchers throughout the world have previously considered the problem of minimising the costs of train delays and have used various optimisation algorithms for differing scenarios. However, little work has been carried out to evaluate and compare the different approaches. Firstly, this thesis compares and contrasts a number of optimisation approaches that have been previously used and applies them to a series of common scenarios. It is found that simple disturbances (i.e. one train delayed) can be managed efficiently using straightforward approaches, such as first-come-first-served. For more complex scenarios, advanced methods are found to be more appropriate. For the scenarios considered in this comparison, ant colony optimisation performed well. Secondly, in order to improve the currently available algorithm so that it can more reliably find optimal or close to optimal results within a practical computation time, a new hybrid algorithm, based on ant colony optimisation, has been developed. In order to evaluate the new approach 100 randomly generated delay scenarios are tested, and a comparison is made between the results of the new algorithm and first-come-first-served, brute force and standard ant colony optimisation. It is shown that the hybrid algorithm has improved performance in terms of optimality and computation speed. Finally, a new multi-stage rescheduling approach for finding an optimal solution over multiple junctions is proposed. A case study is considered, and it is shown that the proposed approach performs well.

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Zhang, Yunlong. "Optimal traffic control for a freeway corridor under incident conditions." Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-145027/.

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Somers, Julia Marie. "Macroscopic Coupling Conditions with Partial Blocking for Highway Ramps." Master's thesis, Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/326572.

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Mathematics
M.S.
We consider the Lighthill-Whitman-Richards traffic model on a network consisting of a highway with an off ramp, connected by a junction. We compare the known coupling conditions for the evolution of traffic at the junction and suggest a novel improvement to the existing conditions. That is, we resolve the spurious effects that arise in standard models, namely clogging of the main highway and vehicle destination changes. We achieve this by tracking vehicle density buildup in the form of a queue, which is modeled by an ODE. We define the solution to the Riemann problem at the junction using the supply and demand functions. The numerical approximation is carried out using a modified Godunov scheme, adjusted to take into account the effects of an emptying queue. Exact and numerical comparisons of the model with existing models verify that the number of vehicles who wish to exit are preserved and the nonphysical clogging of the main highway does not occur.
Temple University--Theses

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Zhu, Boyuan M. Eng Massachusetts Institute of Technology. "Traffic condition tracking and visualization in virtual city testbed." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66822.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 31).
Computer traffic simulation is a tool widely used to understand how humans behave under varying traffic conditions. The Virtual City Testbed is a traffic simulation framework built to closely model human behavior by allowing direct user interaction in the simulation. Using the testbed, human subjects can remotely control vehicles in the virtual environment. A virtual positioning system (VPS) is displayed with the testbed client. It tracks and visualizes traffic, disruptions, and tolls local to the user's position. As traffic conditions shift, the VPS dynamically updates to reflect the changes. Together, the testbed and VPS provide an environment for studying how traffic conditions affect decision making.
by Boyuan Zhu.
M.Eng.

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Ni, Ming. "Using Social Media to Predict Traffic Flow under Special Event Conditions." Thesis, State University of New York at Buffalo, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1546950.

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Social media is great resource of user-generated contents. Public attention, opinion and hot topics can be captured in the social media, which provides the ability to predict human related events. Since social media can be retrieved in real time with no building cost and no maintenance cost, traffic operation authorizes probably identify the social media data as another type sensor for traffic demand. In this thesis, we aim to use social media information to assist traffic flow prediction under special event conditions. Specially, a short-term traffic flow prediction model, incorporated with tweet features, is developed to forecast the incoming traffic flow prior sport game events. Both tweet rate features and semantic features are included in the prediction model. We examine and compare the performance of four regression methods, respectively autoregressive model, neural networks model, support vector regression, and k-nearest neighbor, with and without social media features. To the end, we show the benefit gained by including social media information in the prediction model and its computational efficiency for potential practical applications.

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Ai, Qingyi. "Length-Based Vehicle Classification Using Dual-loop Dataunder Congested Traffic Conditions." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1384869552.

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Marzuoli, Aude Claire. "En-route air traffic optimization under nominal and perturbed conditions, on a 3D data-based network flow model." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43639.

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Air Traffic Management (ATM) aims at ensuring safe and efficient movement of aircraft in the airspace. The National Airspace System is currently undergoing a comprehensive overhaul known as NextGen. With the predicted growth of air transportation, providing traffic flow managers with the tools to support decision making is essential. These tools should aid in accommodating the air traffic throughput increase, while limiting controller workload and ensuring high safety levels. In the National Airspace System (NAS), the goal of en-route Traffic Flow Management (TFM) is to balance air traffic demand against available airspace capacity, in order to ensure a safe and expeditious flow of aircraft, both under nominal and perturbed conditions. The objective of this thesis is to develop a better understanding of how to analyze, model and simulate air traffic in a given airspace, under both nominal and degraded conditions. First, a new framework for en-route Traffic Flow Management and Airspace Health Monitoring is developed. It is based on a data-driven approach for air traffic flow modeling using historical data. This large-scale 3D flow network of the Cleveland center airspace provides valuable insight on airspace complexity. A linear formulation for optimizing en-route Air Traffic is proposed. It takes into account a controller taskload model based on flow geometry, in order to estimate airspace capacity. The simulations run demonstrate the importance of sector constraints and traffic demand patterns in estimating the throughput of an airspace. To analyze airspace degradation, weather blockage maps based on vertically integrated liquid (VIL) are incorporated in the model, representing weather perturbations on the same data set used to compute the flows. Comparing the weather blockages and the network model of the airspace provides means of quantifying airspace degradation. Simulations under perturbed conditions are then run according to different objectives. The results of the simulations are compared with the data from these specific days, to identify the advantages and drawbacks of the present model.

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Bain, Nicolas Charles Patrick. "Traffic models from a velocity point of view and implementation of traffic conditions in excess fuel consumption estimates." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/99591.

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Thesis: S.M., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 157-161).
The estimation of excess fuel consumption due to pavement - vehicle interactions (PVI) is receiving an increasing amount of attention, for it has major economic and ecological implications for the design and maintenance of road networks. As any dissipative mechanisms, the ones we find in the interaction of the pavement and the vehicles are highly dependent on the velocity of the agents in the system, hence the travelling speed of the vehicles. In this work, we propose a coupling of mechanistic dissipative models with evaluation of velocity profiles which shall enable a higher accuracy in the prediction of excess fuel consumption. We focus our attention on the simulation of the probability density functions associated with the velocity of vehicles on a single lane road, for agent-based and cellular automata models. While our approach neglects the influence of lane interactions on the velocity probability distribution, this simulation-based method enables us to obtain predictions of the dissipation resulting from both deflection and roughness of the pavement on any highway segment as a function of the traffic flow. It is shown that taking into account the presence of traffic jams instead of assuming all vehicles traveling at maximum velocity, as is done to obtain usual estimates, increases the deflection-induced dissipation per vehicle per traveled length and reduces the roughness-induced one. This difference is, however, shown to lose in magnitude when the temperature of the environment increases.
by Nicolas Charles Patrick Bain.
S.M.

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Kastenhofer, Ilona Ottilia. "Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/64908.

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The methodology to measure the performance of urban streets was significantly revised in the latest edition of the Highway Capacity Manual (HCM 2010). Urban Streets, which include urban and suburban signalized arterial highways, typically serve the four modes of transportation (auto, transit, pedestrian and bicycle) and are frequently congested. Analyzing both recurrent and non-recurrent conditions is essential. In this dissertation, the author addressed several urban streets related issues by developing an alternative method to measure recurrent multimodal conditions on urban streets; gathering feedback relating to the key elements of the developed method; and developing a probabilistic method to analyze and measure non-recurrent conditions. Real life sample applications were performed for both developed methods. The developed multimodal method addresses the following: (1) the use of level of service (LOS) step functions; (2) the comparability of LOS results across modes; (3) the impacts of modes on other modes; (4) the establishment of thresholds; (5) accuracy; and (6) user perceptions in measuring multimodal conditions on urban streets. Feedback gathered from transportation professionals through focus group meetings and surveys supported most of the features of the developed multimodal method and provided default values for method application. They were divided on the naming of condition levels and on the number of condition levels to use. Non-recurrent conditions were addressed through the development of a Markovian probabilistic method to analyze and measure the resilience of congested, signalized, arterial highways, for which availability of existing analytical tools is limited. The method results provide a plexiform of information about the rate and speed of recovery of the arterial traffic flow.
Ph. D.

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Millington, Paul James. "An investigation of the selective catalytic reduction of nitrogen monoxide by hydrocarbons under oxidising conditions." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262564.

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Amata, Hideomi, Chiyomi Miyajima, Takanori Nishino, Norihide Kitaoka, and Kazuya Takeda. "Prediction model of driving behavior based on traffic conditions and driver types." IEEE, 2009. http://hdl.handle.net/2237/13899.

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Fu, Ting. "Effects of adverse winter weather conditions on highway traffic and driver behavior." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123259.

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This research looks into the impact of adverse winter weather conditions on highway driver behaviors using microscopic data from loop detectors and video cameras (e.g., hourly average speed, trajectories, lane changes, time-to-collisions measures). This thesis is composed of two main sections in addition to the introductory section: i) direct and lagged effects of adverse weather on hourly speeds and volumes; and ii) direct effect of adverse weather on driver behaviors (microscopic) measured at the vehicle level using video data. The first part of the thesis presents a review of literature related to past research on the topic. The second part investigates the direct and lagged effects of adverse winter weather conditions on the operating speed in a number of highway segments in Ontario using a time-series approach. This is complemented by the analysis of hourly traffic volumes in the region of Montreal, Canada, using data from magnetic loop detectors as well. In speed modeling, the effect of adverse weather was studied using data from multiple sites including both urban and rural highways, considering weekdays versus weekends separately. For this purpose, a large dataset containing hourly traffic data, weather variables (e.g., temperature, snow, wind speed), and surface conditions was used. A few previous studies have examined the effect of snowstorms on traffic parameters; however, little research has been done regarding the spillover effects (lagged effects) that adverse weather conditions may have on travel demand and traffic patterns. Extreme events or weather conditions might have a strong effect on traffic conditions not only during the events, but also before and after the events. In this study, time-series regression techniques―in particular, Autoregressive Integrated Moving Average (ARIMA) models―were used to model the highway operating speed. These methods are able to consider the serial correlation among error terms. The results indicate that snowstorms have a statistically significant effect on the speed. The lagged effects are however offset by the time and intensity of winter maintenance operations during and after the event. The effect of weather also varies depending on the type of site (urban or rural) and day of the week. Similarly, the effects of different weather variables including their lagged effects were analyzed using hourly traffic volume data. Despite the fact that information of the road surface condition was not available, this analysis is in accordance with previous finding, showing the utility of ARIMA approaches in modeling the highway volume as well. The results of this study can be applied in quantifying the mobility effect of winter weather and benefits of winter road maintenance. In recent years, driver behavior analysis using microscopic (vehicle level) data is a topic that is attracting more attention in road safety analysis. This popularity has brought about research in many different innovative techniques and microscopic measures used to quantify and analyze driver behavior. In the second part of this thesis, it demonstrates a method of analyzing driver behavior using video data approach. This thesis elucidates both a manual and an automated, computer-based method to analyze driver behavior. It also uses the computer-based method to evaluate the effect of adverse winter weather conditions on the driver behavior of highway users. Both the manual and the automated approaches have been used with 15 video recordings obtained from three different locations on the Don Valley Parkway (DVP) in Toronto, Ontario. The results demonstrate the effectiveness of the automated method in analyzing driver behavior, as well as in evaluating the impact of adverse winter weather conditions on driver behavior.
La thèse présente l'impact des conditions météorologiques hivernales défavorables sur les comportements des conducteurs de la route à l'aide de données microscopiques de détecteurs de mouvement et des caméras vidéo (e.g., la vitesse horaire moyenne, les trajectoires, les changements de voie, des mesures de temps à la collision) La thèse est composée de deux sections principaux, en plus de l'introduction: i) les effets directs et décalés des conditions météorologiques défavorables sur la vitesse et le volume horaire; et ii) l'effet direct des conditions météorologiques défavorables sur le comportement microscopique des conducteurs mesurées au niveau du véhicule à l'aide de données vidéo.La première partie de la thèse propose une revue de la littérature sur le sujet. La deuxième partie examine les effets directs et décalés des conditions météorologiques hivernales défavorables sur la vitesse opérationnelle dans un certain nombre de segments de la route en Ontario en utilisant une approche de séries chronologiques. Ceci est complété par l'analyse des volumes de trafic horaires dans la région de Montréal, au Canada, en utilisant également les données de détecteurs de boucles magnétiques. Pour modéliser la vitesse, l'effet des conditions météorologiques défavorables a été étudié en utilisant des données provenant de plusieurs sites, dont deux autoroutes urbaines et rurales. Les jours de semaine et les week-ends ont été considérés séparément. Certaines études antérieures ont examiné l'effet de tempêtes de neige sur les paramètres de trafic, mais peu a été fait en ce qui concerne les effets d'entraînement (effets différés) que les conditions météorologiques défavorables peuvent avoir sur la demande de voyage et sur les modèles de trafic. Dans cette étude, les techniques de régression chronologique - en particulier les modèles autorégressives moyennes mobiles intégré (ARIMA) - ont été utilisées pour modéliser la vitesse opérationnelle de l'autoroute. A partir des résultats, on peut déduire que les tempêtes de neige ont un effet statistiquement significatif sur la vitesse. Les effets décalés sont toutefois compensés par la durée et l'intensité des opérations d'entretien hivernal pendant et après l'événement. L'effet de la météo varie aussi en fonction du type de site (urbain ou rural) et le jour de la semaine. Les résultats de cette étude peuvent être appliqués pour quantifier l'effet de la mobilité des conditions météorologiques et les avantages de l'entretien des routes en hiver. De même, les effets des différentes variables météorologiques, y compris leurs effets décalés ont été analysés à l'aide des données de volume de trafic. Malgré que l'information de l'état de surface de la route n'était pas disponible, cette analyse est conforme aux financements antérieurs, montrant également l'utilité des approches ARIMA sur le volume de la route. Au cours des dernières années, le comportement du conducteur en utilisant des données microscopique (niveau du véhicule) est un sujet qui attire plus d'attention à l'analyse de la sécurité routière. Cette popularité a entraîné des recherches sur de nombreux techniques novatrices et le développement de mesures microscopiques utilisées pour quantifier et analyser le comportement du conducteur. Dans la deuxième partie de cette thèse, une méthode est démontrée pour analyser le comportement du conducteur en utilisant l'approche de données vidéo. Cette thèse présente à la fois une démarche manuel et une méthode informatique automatisée pour analyser le comportement du conducteur. Les méthodes manuel et automatique sont utilisées sur 15 enregistrements vidéo obtenus à trois endroits différents sur le Don Valley Parkway (DVP) à Toronto, en Ontario. Les résultats démontrent l'efficacité de la méthode automatisée pour analyser le comportement du conducteur, ainsi que dans l'évaluation de l'impact des conditions météorologiques hivernales défavorables sur le comportement des conducteurs.

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Pfeil, Diana Michalek. "Optimization of airport terminal-area air traffic operations under uncertain weather conditions." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67716.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2011.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 153-158).
Convective weather is responsible for large delays and widespread disruptions in the U.S. National Airspace System, especially during summer. Although Air Traffic Flow Management algorithms exist to schedule and route traffic in the face of disruptions, they require reliable forecasts of airspace capacity. However, there exists a gap between the spatial and temporal accuracy of aviation weather forecasts (and existing capacity models) and what these algorithms assume. In this thesis we consider the problem of integrating currently available convective weather forecasts with air traffic management in terminal airspace (near airports). We first demonstrate how raw convective weather forecasts, which provide deterministic predictions of the Vertically Integrated Liquid (the precipitation content in a column of airspace) can be translated into reliable and accurate probabilistic fore- casts of whether or not a terminal-area route will be blocked. Given a flight route through the terminal-area, we apply techniques from machine learning to determine the probability that the route will be open in actual weather. This probabilistic route blockage predictor is then used to optimize terminal-area operations. We develop an integer programming formulation for a 2-dimensional model of terminal airspace that dynamically moves arrival and departure routes to maximize expected capacity. Experiments using real weather scenarios on stormy days show that our algorithms recommend that a terminal-area route be modified 30% of the time, opening up 13% more available routes during these scenarios. The error rate is low, with only 5% of cases corresponding to a modified route being blocked while the original route is in fact open. In addition, for routes predicted to be open with probability 0.95 or greater by our method, 96% of these routes are indeed open (on average) in the weather that materializes. In the final part of the thesis we consider more realistic models of terminal airspace routing and structure. We develop an A*-based routing algorithm that identifies 3-D routes through airspace that adhere to physical aircraft constraints during climb and descent, are conflict-free, and are likely to avoid convective weather hazards. The proposed approach is aimed at improving traffic manager decision-making in today's operational environment.
by Diana Michalek Pfeil.
Ph.D.

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Weber, Nicole. "Using landscape metrics to assess traffic noise, air pollution and temperature conditions." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17196.

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Urbane Räume sind aufgrund ihrer hohen Bevölkerungsdichtes sowie gesellschaftlichen und wirtschaftlichen Bedeutung besonders exponiert gegenüber äußeren Einflüssen und Umweltbelastungen. Sie sind klimatische Ungunsträume, in welchen sich besonders bei starken Hitzeereignissen eine hohe gesundheitliche Belastung entwickelt. Zudem sind Städte durch eine beträchtliche Lärmbelastung und Luftverschmutzung belastet. In der vorliegenden Dissertation wurde eine umweltbezogene Risikoanalyse anhand von Landschaftsstrukturmaßen umgesetzt, in dem Leipziger Stadtstrukturtypen hinsichtlich ihrer Belastung durch Verkehrslärm, Feinstaub und Oberflächentemperaturen untersucht wurden. Die höchsten Belastungen an Lärm und Feinstaub, als auch die höchsten Oberflächen-temperaturen treten in den Wohngebieten auf. Grünflächen und Kleingartenanlagen bilden dagegen Erholungsräume mit geringeren Oberflächentemperaturen und hohen Anteilen gering belasteter Flächen durch Lärm und Feinstaub. Eine gleichzeitige Analyse der vorhandenen Strukturmerkmale, Bebauungshöhe und Anteil an bebauter Fläche, ermöglichte die Betrachtung der Beeinflussung durch bestimmte Baustrukturen und deren Anordnung. Der Einsatz von Landschaftsstrukturmaßen ermöglicht eine kostengünstige und effiziente Analyse von Umweltbelastungen wie Lärm, Feinstaub und Hitze von unterschiedlichen Stadtstrukturtypen. Anhand von Landschaftsstrukturmaßen können die mit Stadtumbau und Neubau einhergehenden Verbesserungen oder Verschlechterungen der Luftschadstoff- und Lärmbelastung sowie Oberflächentemperaturen identifiziert werden.
In cause of their high population-density as well as social and economic importance, urban areas are particularly sensitive to external influences and environmental pollution. Under climate change and high noise and air pollution, green spaces, such as parks and urban forests, become increasingly important. The identification of highly polluted areas within the city or its residential districts can be helpful for city planners to proactively plan these areas and create open spaces. Sustainable effects on well-being and human health will be the outcome. The dissertation implemented an environmental risk analysis has been based on the quantitative concept of the landscape metrics. Typical structure types in Leipzig have been analysed for their exposure to traffic noise, air pollution and surface temperatures. The highest exposures of noise and airborne particles, as well as the highest surface temperatures were found in residential areas. In contrast green spaces and allotments form recreation areas with lower surface temperatures and high percentages of low exposured areas of noise and air pollution. A simultaneous analysis of existing structural features, building height and proportion of built area, allowed the consideration of the influence of certain structural conditions. The use of landscape metrics offered a cost-efficient analysis of the structure types and the prevailing exposure of the three environmental stressors. Bases on metrics such as edge and patch density and diversity indicés, land use structure changes going along with improvements or worsening of air and noise pollution as well as surface temperatures can be straightforward identified.

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Schmitt, Laura E. "Calibration of the HCM 2010 single-lane roundabout capacity equations for Georgia conditions (Phase 2)." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50413.

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The operational performance of an existing or proposed roundabout can be assessed through capacity models. In order to provide improved capacity predictions for existing and proposed Georgia roundabouts, the 2010 HCM roundabout capacity equations need to be locally calibrated based on Georgia drivers. The purpose of this study is to collect field data necessary to calculate follow-up and critical headways at Georgia roundabouts in order to calibrate the 2010 HCM capacity equations to yield improved capacity predictions. The research team filmed 28 approaches at thirteen Georgia roundabouts for a total of 56.5 hours. The video was processed manually using an in-house computer program. Based on analyst keystrokes during the video review the program would extract timestamps of events that are necessary for calculating follow-up and critical headway. The follow-up and critical headway values were calculated for two different data sets: 1) including exiting vehicles and 2) excluding exiting vehicles. The critical and follow-up headway for an analysis including exiting vehicles is 4.192 seconds and 2.788 seconds respectively. The critical and follow-up headway for an analysis excluding exiting vehicles is 4.747 seconds and 3.265 seconds respectively. This study found that including the exiting vehicles impacts the capacity. The capacity increases or decreases based on the percentage of conflicting vehicles that are exiting vehicles. In addition, this study’s calibrated model excluding exiting vehicles predicts higher capacity than the 2010 HCM model that GDOT recommends which also excludes exiting vehicles.

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Gurupackiam, Saravanan. "Use of microscopic traffic simulation and field data to investigate saturated and free flow traffic conditions at arterial signals." Thesis, [Tuscaloosa, Ala. : University of Alabama Libraries], 2009. http://purl.lib.ua.edu/2164.

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Domec, Vincent. "Endommagement par fatigue des enrobés bitumineux en condition de trafic simulé et de température." Bordeaux 1, 2005. http://www.theses.fr/2005BOR13117.

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L'essai de fatigue normalisé caractérisé le comportement en fatigue des enrobés bitumineux. La loi de fatigue issue des essais est utilisée pour le dimensionnement des chaussées. Toutefois, la performance prévue par la loi de fatigue est pessimiste par rapport à celle de la chaussée. De fait, un coefficient de calage KC est employé. Deux facteurs permettent d'expliquer la différence de performance : la température et les temps de repos. Les essais avec périodes de repos permettent un gain de durée de vie par rapport aux essais de fatigue continue qui s'explique par la capacité des enrobés à récupérer de la raideur. Nous vons créé un essai de fatigue dit "à trafic simulé" afin de déterminer une loi de fatigue avec repos et de quantifier la part de l'autoréparaion et de la thixotropie dans la récupération de raideur. Les résultats montrent que la durée de vie est une fonction de la température, de la déformation et du temps de repos. La différence de performance observée entre les essais de fatigue continue et la chaussée réelle est due à l'autoréparation des enrobés durant les périodes de repos. Notre étude du comportement d'une chaussée réelle montrent que le modèle de durée de vie issu des essais "à trafic simulé" permet une meilleure prédiction du comportement de la chaussée que l'essai de fatigue continue. Cette prédition reste pessimiste par rapport au comportement de la chaussée réelle qui est expliqué par des conditions de sollicitation non prises en compte par nos essais. L'essai à "trafic simulé" à deux phases étudie le comportement d'un enrobé suite à un renforcement. L'étude du comportement d'une GB dans ces conditions montre que le gain de durée de vie obtenu grâce au renforcement est fonction de l'instant et du niveau de rechargement.

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Heidaripak, Samrend. "PREDICTION OF PUBLIC BUS TRANSPORTATION PLANNING BASED ON PASSENGER COUNT AND TRAFFIC CONDITIONS." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-53408.

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Artificial intelligence has become a hot topic in the past couple of years because of its potential of solving problems. The most used subset of artificial intelligence today is machine learning, which is essentially the way a machine can learn to do tasks without getting any explicit instructions. A problem that has historically been solved by common knowledge and experience is the planning of bus transportation, which has been prone to mistakes. This thesis investigates how to extract the key features of a raw dataset and if a couple of machine learning algorithms can be applied to predict and plan the public bus transportation, while also considering the weather conditions. By using a pre-processing method to extract the features before creating and evaluating an k-nearest neighbors model as well as an artificial neural network model, predicting the passenger count on a given route could help planning of the bus transportation. The outcome of the thesis was that the feature extraction was successful, and both models could successfully predict the passenger count based on normal conditions. However, in extreme conditions such as the pandemic during 2020, the models could not be proven to successfully predict the passenger count nor being used to plan the bus transportation.

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KOLIMI, PRAGATHI REDDY. "IMPROVEMENTS OF DILEMMA ZONE OPERATION AT HIGH-SPEED INTERSECTIONS IN MIXED TRAFFIC CONDITIONS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1493849047813236.

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Yunus, Muhammad Naim. "Blocking in teletraffic systems under nonstationary arrival and service conditions /." Title page, contents and summary only, 1985. http://web4.library.adelaide.edu.au/theses/09PH/09phy95.pdf.

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43

Khalifa, Abderrahmen. "Contribution à la modélisation microclimatique des situations hivernales en milieu urbain." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0295/document.

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En viabilité hivernale, la prévision de l’état de surface des infrastructures s’avère indispensable, et permet une anticipation, une meilleure coordination et une efficacité d’intervention des services d’exploitation. La majorité des pays dispose de modèles de prévision de la température de surface d'infrastructures et des routes en particulier (TSR). La complexité de ces outils d’aide à la décision est croissante, pour servir au mieux les usagers et l’exploitant. Le microclimat urbain influence le bilan énergétique de surface selon différents processus : radiatifs, aérodynamiques et hydrologiques. Néanmoins, d’autres processus physiques anthropiques influencent cette TSR, tel que le trafic. Des travaux ont été menés par le passé concernant l’apport énergétique du trafic dans le bilan thermique de la ville. Celui-ci a fait l’objet d’études sur les périodes estivales et les îlots de chaleur urbains associés. Cependant, dans les cas de dégradations des conditions hivernales de circulation, ces apports énergétiques ont été intégrés de façon marginale dans la modélisation des paramètres de surface de la route. L’absence de cette contribution du trafic dans la modélisation du bilan énergétique de surface explique, dans une certaine limite, la prévision imparfaite de l’état de surface de la route. La bibliographie recense plusieurs études conduites afin d’identifier et de quantifier ces effets du trafic. Elles n'ont pas ou peu traité la perte ou le gain d'énergie causé par le passage des véhicules sur le bilan énergétique de surface, ou sur la modélisation de la TSR. Dans la présente étude, deux approches ont été proposées pour paramétrer le trafic dans le modèle numérique Town Energy Balance (TEB), l'une globale et la seconde détaillée. Leur analyse comparée indique que la seconde a significativement amélioré les résultats de la modélisation de la TSR. Les apports thermiques du trafic ont augmenté la TSR de 2 à 4°C pour la rapprocher des mesures expérimentales (écart de 0.5 à 1°C en moyenne). Elle est le résultat de l’effet cumulatif des différents processus physiques associés au trafic, et varie en fonction de ses paramètres (densité, vitesse de circulation, fluidité, etc.). Une étude de sensibilité a été menée afin d’apprécier les processus physiques responsables de l’amélioration de la TSR. Les résultats indiquent que l’effet turbulent, la densité de flux radiatif ainsi que la densité de flux due aux frottements des pneumatiques contribuent le plus à l'augmentation la TSR. Néanmoins la contribution énergétique de chacun de ces processus dépend à la fois des paramètres du trafic et des conditions météorologiques. Cette étude a présenté également une analyse préliminaire de l’influence de la lame d’eau présente en surface sur la TSR. Cette dernière décroit en fonction de l’épaisseur de la lame d’eau. Les facteurs anthropiques tels que le trafic et l’adjonction de fondants routiers sur la lame d’eau présente en surface sont décrits et discutés, et une paramétrisation proposée en perspectives
In winter maintenance, forecasting the infrastructure surface status is mandatory, to allow anticipation, better coordination and efficiency of services. The majority of countries have forecast models of the infrastructure surface temperature and especially roads one (RST). The complexity of these decision tools is growing, to best serve the users and managers. The urban microclimate influences the surface energy balance according to various processes: radiative, aerodynamic and hydrologic. However, other anthropogenic physical processes influence this RST, such as traffic. Studies have been carried out in the past about the traffic heat input in the town heat balance. These were conducted on the summer periods and associated urban heat islands. However, in case of traffic in adverse winter conditions, these energy contributions were marginally integrated into the modeling of the road surface parameters. The absence of this traffic's contribution in the surface energy balance modeling explains, to a given limit, the imperfect forecasting of road surface status. The literature identifies several studies conducted to identify and to quantify these effects of traffic. They have insufficiently or not treated the loss or gain on energy caused by circulating vehicles on the surface energy balance, or on modeling the RST. In this study, two approaches have been proposed to parameterize the traffic in the Town Energy Balance (TEB) numerical model, this first one being overall and the second one detailed. Their comparative analysis indicates that the second significantly improved the results of the RST modeling. The traffic heat inputs increased RST by 2 to 4°C, results being then closer to experimental measurements (average difference of 0.5 to 1°C). It is the result of the cumulative effect of the various traffic physical processes, and varies according to its parameters (density, vehicle velocity, fluidity, etc.). A sensitivity analysis was conducted to assess the physical processes responsible for the improvement of the RST. The results indicate that the turbulent effect, the radiative heat flux and flux density due to tires friction represent the greatest contribution to RST increase. Nevertheless the energy contribution of each of these processes depends both traffic parameters and weather conditions. This study also presented a preliminary analysis of the influence of a water layer over the surface on the RST. The latter decreases as a function of the thickness of the water layer. Anthropogenic factors such as traffic and the addition of de-icing products into the water layer present on the surface are described and discussed, and a parameterization proposed as a perspective

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Henderson, Jeffrey Michael. "Collaborative En Route Airspace Management Considering Stochastic Demand, Capacity, and Weather Conditions." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26536.

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The busiest regions of airspace in the U.S. are congested during much of the day from traffic volume, weather, and other airspace restrictions. The projected growth in demand for airspace is expected to worsen this congestion while reducing system efficiency and safety. This dissertation focuses on providing methods to analyze en route airspace congestion during severe convective weather (i.e. thunderstorms) in an effort to provide more efficient aircraft routes in terms of: en route travel time, air traffic controller workload, aircraft collision potential, and equity between airlines and other airspace users. The en route airspace is generally that airspace that aircraft use between the top of climb and top of descent. Existing en route airspace flight planning models have several important limitations. These models do not appropriately consider the uncertainty in airspace demand associated with departure time prediction and en route travel time. Also, airspace capacity is typically assumed to be a static value with no adjustments for weather or other dynamic conditions that impact the air traffic controller. To overcome these limitations a stochastic demand, stochastic capacity, and an incremental assignment method are developed. The stochastic demand model combines the flight departure uncertainty and the en route travel time uncertainty to achieve better estimates for sector demand. This model is shown to reduce the predictive error for en route sector demand by 20\% at a 30 minute look-ahead time period. The stochastic capacity model analyzes airspace congestion at a more macroscopic level than available in existing models. This higher level of analysis has the potential to reduce computational time and increase the number of alternative routing schemes considered. The capacity model uses stochastic geometry techniques to develop predictions of the distribution of flight separation and conflict potential. A prediction of dynamic airspace capacity is calculated based on separation and conflict potential. The stochastic demand and capacity models are integrated into a graph theoretic framework to generate alternative routing schemes. Validation of the overall integrated model is performed using the fast time airspace simulator RAMS. The original flight plans, the routing obtained from an integer programming method, and the routing obtained from the incremental method developed in this dissertation are compared. Results of this validation simulation indicate that integer programming and incremental routing methods are both able to reduce the average en route travel time per flight by 6 minutes. Other benefits include a reduction in the number of conflict resolutions and weather avoidance maneuvers issued by en route air traffic controllers. The simulation results do not indicate a significant difference in quality between the incremental and integer programming methods of routing flights around severe weather.
Ph. D.

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Zheng, Zijian. "Heavy Vehicle Impact on Rural Two Lane Highway Segments Operating Under Various Levels of Service Conditions." Thesis, North Dakota State University, 2014. https://hdl.handle.net/10365/27270.

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Oil boom in Western North Dakota State brings increasing number of oil trucks. The distinct characteristics of heavy vehicles such as oil trucks: low speed, large size, and slow accelerate and decelerate results in inaccuracy in traffic capacity forecasting and safety analysis. In this research, to calculate passenger car equivalent (PCE) factor of heavy vehicles, such as oil trucks, on two-lane rural highway, an improved analytical method based on headway and delay is introduced. It considers several elements that have effect on PCE factor: vehicle speed, safety passing time, headway distribution, level of service (LOS), and delay to downstream traffic. The new set of PCE factor values are classified into three groups corresponding to different LOS.

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46

Mohagheghi, Ali. "Effect of Pavement Condition on Traffic Crash Frequency and Severity in Virginia." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/100129.

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Previous studies show that pavement condition properties are significant factors to enhance road safety and riding experience, and pavements with low quality might have inadequate performance in terms of safety and riding experience. Pavement Management System (PMS) databases include pavement properties for each segment of the road collected by the agencies. Understanding the impact of road characteristics on crash frequency is a key step to prevent crashes. Whereas other studies analyzed the effect of different characteristics such as International Roughness Index (IRI), Rutting Depth (RD), Annual Average Daily Traffic (AADT), this thesis analyzed the effect of Critical Condition Index (CCI) on crash frequency, in addition to the other factors identified in previous studies. Other characteristics such as Percentage of Heavy Vehicles, Road Surface Condition, Road Lighting Condition, and Driver Conditions are taken into the consideration. The scope of the study is the interstate highway system in Fairfax County, Virginia. Negative Binomial, Least Square and Nominal Logistic Models were developed, showing that the CCI value is a significant factor to predict the number of crashes, and that it has different effect for different values of AADT. The result of this study is a substantial step towards developing an integrated transportation control and infrastructure management framework.
Master of Science
Many factors cause crashes in the roads. Although there is a common sense that road characteristics such as asphalt quality are important in terms of road safety, there are few studies that scientifically prove that statement. In addition, asphalt maintenance decisions making process is mainly based on cost benefit optimization, and traffic safety is not considered at the process. The purpose of this study is to analyze crashes and road characteristics related to each crash to understand the effect of those characteristics on crash frequency, and eventually, to build a model to predict the number of crashes at each part of the road. The model can help transportation agencies to have a better understanding in terms of safety consequences of their infrastructure management plans. The scope of this study is the highway interstate system in Northern Virginia. Results suggest that pavement condition has a significant impact on crash frequency.

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Tagliaferri, Anthony Paul. "Use and Comparison of Traffic Simulation Models in the Analysis of Emergency Evacuation Conditions." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-03232005-185245/.

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The evacuation of vulnerable coastal areas in the event of an emergency such as an impending hurricane has become a significant safety issue due to the rapid growth of both permanent and tourist populations in these areas. Highway capacity has often not been upgraded in line with this demand growth. In the case of Hurricane Floyd in 1999, evacuations of areas of North and South Carolina resulted in several highly congested primary highways and, as a result, several states created Lane Reversal Plans for interstates and/or divided highways along evacuation routes. However, these plans were created with little data to rely on as to their efficiency. A major research study was funded by the North Carolina Department of Transportation (NCDOT) to use simulation modeling to investigate the effects of the Interstate 40 Lane Reversal Plan on the evacuation of Wilmington and New Hanover County, North Carolina. In addition to the analysis of the effects of lane reversal, a side-by-side comparison of the CORSIM and VISSIM simulation models was performed on the highway network based on demand estimates provided by a demand study performed for the United States Army Corps of Engineers and the Federal Emergency Management Agency (FEMA). Analysis using CORSIM and VISSIM showed lane reversal to provide considerable capacity increases to traffic attempting to exit New Hanover County via Interstate 40, which had significantly increased throughput and decreased queues within New Hanover County in the event of large-scale evacuations.

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48

Tornaris, George Andreas. "Traffic flow management under emergency conditions in and around the Virginia Tidewater area tunnels." Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/101325.

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Most vehicular tunnels, due to their restrictive and confined environment require continuous traffic surveillance and control. This is achieved by a variety of systems like closed circuit TV monitoring, personnel stationed in the tunnel, overheight & speed detectors and others. Traffic flow data were obtained from the Interstate 64(I -64) Hampton Roads Bridge-Tunnel. The data were analyzed and conclusions were drawn about traffic flow behavior at the different tunnel sections. During the operation of a tunnel, capacity reductions are often experienced due to temporary lane closures. These could result from incidences occurring in the tunnel area or due to regular maintenance activities. This work concentrates on the former case. A microcomputer model called Queue and User Cost Evaluation of Work Zones(QUEWZ) was employed in studying lane closure scenarios for the Virginia Tidewater Area Tunnels. In case of significant capacity reductions or complete blockages of directions of travel, it is desired to know beforehand the impact expected on the surrounding network. Traffic management actions like rerouting policies could be implemented and thus alleviate the problem. MASSVAC2, a computer simulation model for mass evacuation under emergency conditions was employed for analyzing different traffic management scenarios.
M.S.

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Yin, Weihao. "Link State Relationships under Incident Conditions: Using a CTM-based Dynamic Traffic Assignment Model." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/44304.

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Urban transportation networks are vulnerable to various incidents. In order to combat the negative effects due to incident-related congestion, various mitigation strategies have been proposed and implemented. The effectiveness of these congestion mitigation strategies for incident conditions largely depends on the accuracy of information regarding network conditions. Therefore, an efficient and accurate procedure to determine the link states, reflected by flows and density over time, is essential to incident management. This thesis presents a user equilibrium Dynamic Traffic Assignment (DTA) model that incorporates the Cell Transmission Model (CTM) to evaluate the temporal variation of flow and density over links, which reflect the link states of a transportation network. Encapsulation of the CTM equips the model with the capability of accepting inputs of incidents like duration and capacity reduction. Moreover, the proposed model is capable of handling multiple origin-destination (OD) pairs. By using this model, the temporal variation of flows over links can be readily evaluated. The visualized prediction of link density variations is used to investigate the link state relationships. By isolating the effects of an incident, the parallel routes of a specific OD pair display the relationship of substituting for each other, which is consistent with the general expectation regarding such parallel routes. A closer examination of the density variations confirms the existence of a substitution relationship between the unshared links of the two parallel routes. This information regarding link state relationship can be used as general guidance for incident management purposes.
Master of Science

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50

Veschambre, Sophie. "Caractérisation et quantification des Eléments Traces Métalliques dans les dépôts et les particules atmosphériques de la vallée d'Aspe - Mise en place d'indicateurs de la Qualité de l'Air." Phd thesis, Université de Pau et des Pays de l'Adour, 2006. http://tel.archives-ouvertes.fr/tel-00118082.

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L'étude des apports atmosphériques des éléments traces métalliques (ETM) dans la vallée d'Aspe (Pyrénées Atlantiques) a un double objectif : (1) établir un état de référence des contaminants métalliques pour le suivi des émissions du trafic routier liés à l'ouverture du tunnel du Somport et, (2) évaluer les sources et les conditions climatologiques qui contribuent aux apports des ETM dans la vallée d'Aspe. La détermination des ETM (Al, Na, Mg, K, V, Mn, Cr, Zn, Cu, Rb, Cd, Sn, Sb, Ba, Ce, Pb et U) et des rapports isotopiques du plomb (208Pb/206Pb, 206Pb/207Pb et 208Pb/207Pb) dans les récepteurs atmosphériques (neiges fraîches, dépôts humides, particules atmosphériques et lichens) a permis de mettre en place des indicateurs de la qualité de l'air. La quantification des ETM a nécessité la mise en oeuvre de protocoles de prélèvements et d'analyses ultra-traces. Les différents récepteurs atmosphériques étudiés permettent d'intégrer une échelle temporelle journalière à pluriannuelle et un gradient spatial dans l'axe Nord-sud de la vallée et en fonction de l'altitude.
La vallée d'Aspe présente un niveau de contamination spécifique des zones éloignées des émissions anthropiques et les contaminants métalliques identifiés sont le Cd, Sb, Zn, Cu, Pb et Sn. Dans sa partie basse, les indicateurs de la qualité de l'air présentent une contribution des contaminants (i) liée aux émissions locales des combustions domestiques, à la pratique saisonnière de l'écobuage et au trafic routier, et (ii) aux sources anthropiques régionales de l'incinération des déchets ménagers, de l'industries métallurgique et des centres urbains. Dans sa partie haute, la vallée est soumise significativement, d'une part, à l'érosion éolienne et, d'autre part, à la contribution des sources du transport à grande échelle de l'hémisphère Nord. La caractérisation des ETM et des rapports isotopiques du plomb dans le tunnel du Somport indique (i) que le trafic routier émet significativement du Cu, Sb, Zn et Ba et (ii) bien que Pb présente de faibles émissions sa composition isotopique montre une source faiblement radiogénique du trafic routier. Toutefois, la faible circulation des véhicules dans la vallée d'Aspe ne permet pas de mettre évidence une contamination significative provenant des émissions du trafic routier.

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Dissertations / Theses on the topic 'TRAFIC CONDITIONS'

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