Situé dans le contexte général de la sécurité routière, et plus particulièrement axé sur la sécurité des véhicules légers (VL) en virages, ce travail de thèse a pour objet de proposer une méthodologie fiabiliste de prédiction de trajectoires à risque, basée sur le traitement statistique et la modélisation probabiliste de trajectoires réelles de VL en virages. La première partie du travail concerne la construction de modèles probabilistes simples et robustes représentatifs des trajectoires réelles observées. Ces modèles sont des transformées de processus aléatoires scalaires normalisés du second ordre, faiblement stationnaires, ergodiques et non gaussiens, et permettent de décrire de façon réaliste la variabilité aléatoire observée du triptyque Véhicule-Infrastructure-Conducteur. Ils permettent aussi, par construction, de s'affranchir d'éventuelles difficultés dans l'alimentation des paramètres dominants qui les gouvernent. La seconde partie est consacrée au développement et à la mise en oeuvre d'une stratégie fiabiliste destinée à associer un niveau de risque à chaque trajectoire en entrée de virage. Basée sur l'emploi conjoint de méthodes probabilistes pour la modélisation des incertitudes, fiabilistes pour l'évaluation des niveaux de risque et statistiques pour la classification et le traitement des trajectoires, cette approche est une réponse réaliste au problème posé. De par sa conception et ses possibilités, la méthodologie fiabiliste proposée est une contribution significative au développement de procédures d'alerte destinées à réduire notablement le nombre d'accidents en virages. / This PhD thesis tackles the general context of road safety, focussing on the safety of light vehicles (LV) in bends. A reliability engineering methodology is proposed to predict dangerous trajectories, based on the statistical processing and probabilistic modelling of actual trajectories in a bend. In the first part of this work, simple and robust probabilistic models are built to describe trajectories measured in an instrumented bend. The models are transforms of scalar normalized second order stochastic processes which are slightly stationary, ergodic and non-Gaussian. They offer a realistic description for the observed random variability of the Vehicle-Infrastructure-Driver system. They also inherently circumvent possible difficulties in the identification of the dominant parameters which control the system. The second part of this work is devoted to the development and implementation of a reliability engineering strategy intended to associate a risk level to each trajectory at a bend entry. Based on the joint use of probabilistic methods for modelling uncertainties, reliability engineering for assessing risk levels and statistics for classifying and processing the trajectories, this approach provides a realistic answer to the tackled problem. From its design and its possibilities, the proposed reliability engineering methodology constitutes a significant contribution to the development of warning procedures the deployment of which are expected to notably reduce the number of accidents in bends.

After World War II, which lasted from 1939 to 1945, the economies of many countries worldwide experienced a boom period. Many people were able to buy private motor vehicles. A consequence of this, however, was that the number of road traffic accidents in these countries has also increased dramatically. From reports over decades it became clear that traffic safety programs that were implemented did not have the desired effect. To evaluate success, countries normally used accident rates or indices based on mathematical formulas. Rates and indices were and are still used to compare accident situations among countries – normally on an annual basis. It seems that motorised countries try to determine a “winner” by recording the lowest accident rates and indices in a specific year. The approaches followed are uncoordinated. In addition to trend analysis, the municipal police managers or road transport and traffic safety fraternity authorities in the various countries could also focus on risk analysis. Risk analysis is used in the industry with its many role players and security and safety can be promoted through this approach in a more scientific manner. Although risks are normally formulated in terms of probability theory, a Risk Score Value model could be of further benefit to road traffic managers. The Risk Score Value could be used to assist authorities to conduct cost effectiveness studies and to prioritize and optimise countermeasures in a holistic integrated manner with a view to reduce road operation risks to an acceptable level.

Les sorties de route en virage constituent une part importante des accidents de la route en France, causes d'environ 30 % des accidents mortels pour 2008. Ces accidents se produisent principalement sur route secondaire ce qui montre le besoin du conducteur d'être assisté dans sa tâche de lecture et de négociation du virage. L'objectif de ce travail est le développement d'une méthodologie d'évaluation du risque encouru par le conducteur lors du franchissement d'un virage afin de mettre en place sur les itinéraires routiers un système d'alerte déclenchée en cas de situation potentiellement dangereuse. La méthodologie menant à l'évaluation du risque est basée sur l'emploi des méthodes probabilistes, permettant de prendre en compte fidèlement les incertitudes inhérentes au conducteur, au véhicule et à l'infrastructure. A l'entrée du virage, un dispositif de mesure renseigne sur la position latérale et la vitesse du véhicule arrivant. Une famille de trajectoires de passage en virage est alors stimulée à partir d'un modèle dynamique de véhicule dont certains paramètres d'entrée dépendent des trajectoires mesurées sur le trafic réel. Des indices de risque associés à des critères de sécurité sont ensuite évalués par des méthodes fiabilistes. Les résultats obtenus sont la détermination et la hiérarchisation des paramètres influents sur les critères de sécurité, ainsi que l'évolution des indices de risque en fonction des conditions initiales en entrée de virage. Les applications réalisées dans le dernier chapitre démontrent le potentiel de la méthodologie fiabiliste proposée et son intérêt dans le domaine de la sécurité routière. / Roadway departure while cornering constitutes a major part of car accidents in France, accounting for nearly 30 % of casualties in 2008. Most of them occur on secondary roads and reveal that drivers need assistance for a safe curve negociation. The subject of this work is the development of a methodology to access the roadway departure risk in order to implement in the road infrastructure warning devices alarming the driver in case of potentially dangerous situations. The application of probabilistic methods for the risk assessment allows an accurate representation of the uncertainties arising from the driver, the vehicle and the road infrastructures. At the entrance of the curve, speed and position of the approaching vehicle are measured. Then, a family of trajectories is simulated from a dynamic model. Some of the model input depend on experimental trajectories measured on the real traffic. Finally, savety criteria are chosen and associated risk indices are calculated using reliability methods.The influence of various parameters of the model are studied, and the obtained results are the evolutions of the risk indices as a function of the measured initial conditions. The probabilistic methodology elaborated in the road safety domain constitute a valuable decision support tool for the alarm triggering.

No description available.

This thesis derives and validates Performance Indicators for Safe Mobility for Older Road Users in Urban Areas. Performance Indicators are objective, auditable parameters, which when used as a set can provide additional information to decision-makers about the operation of the transport system. Great Britain, in common with many countries across Europe has an ageing population. The proportion of older people who hold a driving licence and have the use of a car is also expected to rise, with future generations of older people travelling further and more frequently than previous generations. Older road users are already over-represented in traffic fatalities, particularly in urban areas. Measures to protect older road users from risk in traffic will be of crucial importance as the population ages. However, against this background the need remains for them to access key facilities such as shops, leisure activities and health care. Maintaining independent mobility is essential in maintaining mental and physical health. Traditionally, outcomes-based measures such as accident or casualty figures have been used to monitor road safety. Techniques such as hotspot analysis have identified locations on the road network where accident numbers are high, allowing modifications to road infrastructure to be designed and implemented. Using outcomes measures alone however, it is difficult to ascribe improvements in accident or casualty figures to particular policy interventions. Moreover, the effect of road safety interventions on other related policy areas mobility being one is impossible to assess without access to detailed, disaggregated exposure data. To make fully informed policy decisions about infrastructure design and how it affects older users, a better understanding of the linkages between safety and mobility is required. Performance Indicators offer the possibility to look at these linked policy objectives within a single framework. Focus group data was used in conjunction with the results of previous studies to identify the infrastructure features which present a barrier to older users safe mobility in urban areas. These included factors which increased risk, such as wide carriageways, complex junctions and fast-moving traffic, and factors which hindered mobility, such as uneven or poorly maintained pavements, poor lighting and traffic intrusion. A thematic audit of infrastructure in a case study city (Coventry) was undertaken, in order that the incidence of such infrastructure could be recorded. It was found that in many areas of the city, safe mobility for older road users was not well provided for, with the majority of locations having barriers to safety and/or mobility for both drivers and pedestrians. The audit data was then used to calculate a set of Performance Indicators, presented via spider graphs, which describe the degree to which the infrastructure caters for the safety and mobility of older drivers and pedestrians. The spider graphs allow for easy comparisons between the different geographical areas, and also between the different policy areas, allowing policy priorities to be identified. The calculated Performance Indicators were validated using case studies collected from the focus group participants. The case studies identified features that affected travel habits by causing a change of route or change of mode, providing evidence of the link between infrastructure design and safe mobility for older users. The results of the Performance Indicator analysis were then compared to accident figures, in order to identify differences between the two approaches, and to understand what policy implications would result from a monitoring framework that used Performance Indicators for safe mobility, rather than outcomes-based measures alone. One implication of the Performance Indicator approach is that it may identify different areas for priority action from those identified by accident or casualty figures. A location which does not have high accident numbers may nevertheless perform poorly on a Safety Performance Indicator measure. This is because older users who feel at risk make different route or mode choices to avoid the infrastructure, the lower accident rate being explained by lower exposure to risk. Conversely, measures to promote independent mobility for older users may increase their accident involvement, not because the environment becomes more risky, but because the exposure of older users to risk increases, because they are willing and able to walk or drive in an area they previously avoided. The thesis concludes that infrastructure design does not currently cater well for the needs of older pedestrians and drivers, and that a framework which incorporated Performance Indicators could make more explicit the trade-offs between safety and mobility, and between different categories of user. This additional information would enable policy makers and practitioners to make more informed decisions about how to prioritise competing objectives in complex urban areas.

No description available.

No description available.

Adverse weather conditions can increase travel risk. Understanding how drivers react to adverse weather, such as rainfall, can aid in the understanding of road safety patterns and traffic operations. This information can in turn be used to improve driver education as well as highway operation through improved signing or the introduction of intelligent highway systems. Hourly rainfall data collected from the Pearson International Airport weather station and City of Toronto traffic data collected at the study site on the Gardiner expressway were used to create event and control pairs. In total, 115 hours with rainfall were matched to control data one week before or after the rainfall event. The traffic sensor at the study site collected speed, volume, and occupancy data at 20-second intervals, which was aggregated to five minutes. In addition, speed deviation and headway data at the 5-minute interval were used for analysis purposes. Two methods were used to test the effects of rainfall on traffic variables and the relationships between them. Matched pair t-tests were used to determine the magnitude of change between event and control conditions for the volume, speed, speed deviation, and headway variables for congested and uncongested traffic conditions. In addition, stepwise multiple linear regression was used to test the effects of rainfall on speed-volume and volume-occupancy relationships. Results of the matched pair t-tests indicated that volumes, speeds, and speed deviations dropped in event conditions, while headways increased slightly. Changes tended to be greater for congested than uncongested conditions. Linear regression results indicated that changes in speed were sensitive to volume conditions, and changes in volume were sensitive to occupancy, although only to a limited extent. Overall, drivers respond to rainfall conditions by reducing both speed and speed deviations, and increasing headway. Reductions in speed are larger in congested conditions, while increases in headway are smaller. Taken in combination, drivers are taking positive steps in order to either maintain or improve safety levels.

Adverse weather conditions can increase travel risk. Understanding how drivers react to adverse weather, such as rainfall, can aid in the understanding of road safety patterns and traffic operations. This information can in turn be used to improve driver education as well as highway operation through improved signing or the introduction of intelligent highway systems. Hourly rainfall data collected from the Pearson International Airport weather station and City of Toronto traffic data collected at the study site on the Gardiner expressway were used to create event and control pairs. In total, 115 hours with rainfall were matched to control data one week before or after the rainfall event. The traffic sensor at the study site collected speed, volume, and occupancy data at 20-second intervals, which was aggregated to five minutes. In addition, speed deviation and headway data at the 5-minute interval were used for analysis purposes. Two methods were used to test the effects of rainfall on traffic variables and the relationships between them. Matched pair t-tests were used to determine the magnitude of change between event and control conditions for the volume, speed, speed deviation, and headway variables for congested and uncongested traffic conditions. In addition, stepwise multiple linear regression was used to test the effects of rainfall on speed-volume and volume-occupancy relationships. Results of the matched pair t-tests indicated that volumes, speeds, and speed deviations dropped in event conditions, while headways increased slightly. Changes tended to be greater for congested than uncongested conditions. Linear regression results indicated that changes in speed were sensitive to volume conditions, and changes in volume were sensitive to occupancy, although only to a limited extent. Overall, drivers respond to rainfall conditions by reducing both speed and speed deviations, and increasing headway. Reductions in speed are larger in congested conditions, while increases in headway are smaller. Taken in combination, drivers are taking positive steps in order to either maintain or improve safety levels.

Criminality takes many forms; a homicide may be defined as criminal activity, as would identity theft--both acts are criminal, yet the responses garnered are quite different. What makes the response for these two acts different? Perhaps societal reaction and tolerance towards these behaviours. Why is it that popular socio-legal discourse takes the position that societal reaction is the result of the information it receives? The focus of my research was to determine whether language affects perception and whether this impacts police and judicial practice. The focus was on the discourse of legal and popular language used to describe motor vehicle incidents that encompass a criminal component of injury and or fatality. I examined the impact of terminology on public and legal perception, as well as societal reactions and tolerance, which were the underlying issues of examination. However, in order to understand reaction and tolerance, I found it important to study the factors that contributed towards public and legal perception. The method of analysis was to examine the terminology used to depict and deliver the news of such incidents. For the purposes of this investigation vehicular negligence is defined as any act or behaviour that contravenes the British Columbia Motor Vehicle Act or is a Criminal Code of Canada offence related to the operation of a motor vehicle. Under the law, a negligent act does not require mens rea, which literally means to have a guilty mind. Therefore, in order to be considered guilty, a person does not necessarily need to have the mental culpability of forecasting or have the intention of inflicting harm. I restricted my area of focus to the region of British Columbia for two primary reasons. First, British Columbia has a higher than average injury and fatality rate resulting from motor vehicle incidents when compared to other provinces in Canada. Second, the area of focus was limited to this province as the result of my direct personal experiences in this provincial context. The parameters of my case study, as indicated above, included only those incidents of vehicular negligence that resulted in bodily injury and or fatality. The form of negligence assessed was not restricted to a specific type of act; rather it included any act that would be considered negligent behaviour on the roads, including but not limited to, driving in excess of the posted speed limit, impaired driving, carelessness, hit and runs, and so forth. My interest was to examine the ways in which these acts are perceived and addressed in public (media) and legal (court) discourse. Focusing on five randomly selected cases involving vehicular negligence, thematic analysis of face-to-face interviews, discourse analysis, and autoethnography were the primary methodologies used for the investigation. At present, there is no shortage of literature examining the cause and effect of specific behaviours in relation to motor vehicle incidents. The shortcoming, however, is that the focus of the literature is primarily centred on the consequences of drunk driving as it relates to the mismanagement of vehicles and the subsequent legal and civil litigations. Some of the literature also addresses social and health costs related to the severity of vehicle negligent incidents. However, there is a dearth of research examining the role of public and legal perceptions as they pertain to vehicular negligence and the impacts on the way in which vehicular negligent incidents are addressed within the courts. The results of this research indicated that terminology does in fact have an impact on perception, and thus negligent incidents on the roads should be referred using terms that are accurate descriptions. Terms such as accidents construe an incorrect understanding of the implications from these types of acts that are a leading health and safety epidemic globally.