Este trabalho enfoca a questão da segurança viária na cidade de Belém. Para a realização do trabalho, foi feito um diagnóstico sobre a gestão da segurança viária na cidade e um estudo dos acidentes de trânsito em dez pontos considerados pelas autoridades como os mais problemáticos, que incluiu a análise das causas dos acidentes através de auditorias de campo. Também são apresentadas algumas propostas para melhoria da gestão da segurança viária na cidade, bem como propostas específicas para redução dos acidentes nos locais estudados. As propostas genéricas para a melhoria da segurança viária em Belém são: campanhas educativas mais eficientes; melhoria da gestão da segurança do trânsito; aumento do número de fiscais de trânsito e melhoria do esquema de fiscalização; montagem de uma equipe permanente de técnicos com objetivo de identificar os pontos críticos, realizar auditorias de campo para identificar as causas dos acidentes e propor e implantar soluções para redução dos mesmos; etc. / This research focuses on the traffic safety problem in Belém city. For the accomplishment of the work, it was made a diagnosis remains to the traffic safety\'s management in the city and a study of the traffic accidents in ten points considered by the authorities as the most problematic, that it included the analysis of the accidents causes through field auditing. Also some proposals for improvement of the traffic safety\'s management in the city, as well as specific proposals for accidents reduction in the studied places. The generic proposals for the traffic safety\'s improvement in Belém are: more efficient educational campaigns; improvement of the traffic safety\'s management; increase of the number of traffic district attorney and improvement of the inspection plan; assembly of a permanent technicians team with goal of identifying the critical points, to accomplish field auditing in order to identify the accidents causes and, to propose and to establish solutions for reduction of the same ones; etc.

As curvas horizontais das rodovias notoriamente colecionam acidentes de trânsito, nos quais geralmente os automóveis derrapam e escapam pela tangente, enquanto que os veículos pesados costumam tombar lateralmente. Os critérios consagrados de projeto geométrico das curvas, consideradas planas, ignoram a propensão dos veículos pesados ao tombamento lateral, confiando apenas nas forças de atrito lateral e na superelevação transversal da via para a manutenção do veículo em trajetória segura. O presente trabalho pretende desenvolver modelo de projeto que forneça margens de segurança tanto contra o escorregamento e o tombamento lateral de veículos pesados (semi-reboques) em curvas horizontais com greide descendente. O modelo proposto no presente estudo é sensível a fatores de segurança intrínsecos e extrínsecos aos veículos, incluindo características geométricas longitudinais e transversais da pista, e a variação da trajetória do veículo dentro da curva. Os resultados obtidos demonstram que os critérios de projeto atuais não garantem a segurança de semi-reboques em curvas descendentes de raio mínimo, principalmente nas curvas de menor velocidade. O critério desenvolvido permite o estabelecimento de margens de segurança para a regulamentação de velocidade em curvas horizontais descendentes já existentes, bem como possibilita a determinação da velocidade de projeto segura para curvas descendentes em novas vias. / The grade effect on highway horizontal curves is notorious for traffic accidents because automobiles tend to skid and leave the road whereas commercial loaded vehicles tend to roll over. The standard criteria for the geometric design of these curves, which are considered flat, ignore the heavy vehicles propensity for rollover by relying solely on the forces of lateral friction and on the road superelevation in order to keep the vehicle in a safe trajectory. The current study has been set out in order to develop a model that will yield margins of safety to prevent skidding and rollover of heavy vehicles (semi-trailers) on horizontal descending highway curves. The model proposed in the present study is sensitive to safety variables both intrinsic and extrinsic to the vehicles, including longitudinal and transversal characteristics of the road, and vehicles trajectory variations at horizontal curves. The results of the study show that the currently adopted safety guidelines do not guarantee the safety of such articulated vehicles on grade curves with minimum radii, mostly at lower speeds curves. As a result, the proposed criteria allows the establishment of margins of safety that can be applied to regulatory speed signs on existing horizontal descending curves, and for the setting of safe design speeds for descending curves on new highways.

Thesis. 1979. Ph.D.--Massachusetts Institute of Technology. Alfred P. Sloan School of Management. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Bibliography: leaves 141-150. / Ph.D.

O objetivo deste trabalho é o desenvolvimento e proposição de modelos matemáticos que possam estimar, com a precisão necessária para efeitos de aplicação prática, o grau ou o nível de segurança de interseções, semaforizadas ou não, usando-se o conceito de oportunidades de conflito de tráfego. O conceito de oportunidade de conflito de tráfego tem sido proposto para obter medidas analíticas de segurança, sendo uma medida correlata de segurança que pode substituir com vantagem as medidas usuais como histórico de acidentes e conflitos de tráfego. Os modelos que usam o conceito de oportunidades de conflito de tráfego necessitam apenas de dados operacionais das interseções, o que torna este parâmetro uma medida potencialmente útil para aplicações práticas na determinação do nível de segurança de um determinado local ou fazer projeções sobre a efetividade de projetos de segurança. São apresentados e discutidos trabalhos de outros autores sobre o assunto, baseados nos quais foram desenvolvidas alternativas às propostas por eles formuladas. Foram analisados pontos não tratados como a aplicação do conceito de oportunidade de conflito de tráfego no período de entreverdes, bem como o estudo de pedestres nas diferentes situações de travessia (nos estudos revisados, somente foi encontrada a análise de travessia de pedestres diante do movimento de conversão à esquerda com fluxo oposto). Foi realizado um estudo piloto numa interseção real com o objetivo de testar metodologias de trabalho de campo, o que permitiu estruturar um trabalho de validação de campo por meio de diagnósticos qualitativos. / The purpose of this work is, through the use of mathematic models, to estimate the level of risk using the concept of traffic conflict opportunity at signalized and unsignalized intersections. The concept of traffic conflict opportunity has been proposed to measure the level of risk, and it is considered as an alternative measure of traffic safety, potentially more useful than the traditional safety measures like traffic accident data or traffic conflict technique. The traffic conflict opportunity models do not require complex field data, only the operational data of the intersection as traffic counts and control parameters are needed. This work presents and analyses other authors studies about this subject, based on which were proposed alternative methods for their formulations. Points such as the safety analysis of the intergreen period using traffic conflict opportunity, not found in those studies, were treated in this work, as well as the pedestrian crossing risk in various situations (in the revised studies, only the analysis of pedestrian crossing risk due to a left turn movement facing an opposing flow was found). In order to test methodologies and to collect field data, it was performed a pilot study at a real intersection. The pilot study allowed to define the goals and the means needed to carry out a field validation by qualitative diagnostic analysis.

Li Xiang. / "September 2004." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (p. 164-172) / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

As an example, the thesis proposes a real-time route guidance system to show how it supports other transportation services, which can then automatically guide vehicles by voice. It illustrates the system architecture and describes the establishment of each part. The concept of agent network is introduced to build up the system. Furthermore, a dynamic route algorithm is presented in brief. A communication system integrating the existing infrastructure is discussed and simulation results are provided to testify the applicability of the proposed wireless data communication system. / Finally, the thesis sums up the contributions achieved and proposes some future works. / For the communication network, the main challenging problems are the large scale of the network, the movement of vehicles that may cause the levity of the network structure, and the large demands on communication capacity. In order to solve these problems, the performance optimization technique is accredited as one of the most important techniques for such a large scale wireless sensor network. This thesis focuses on the research in the following aspects. First, the optimal combination of the duty cycle, one of the most important parameters, is introduced to optimize the system performance. A duty cycle optimization model is put forward based on calculating n-times reachable matrix. Now that the parameter optimization model can be boiled down to a NP-hard problem, an improved genetic algorithm is introduced to solve the problem. The computational procedure and efficiency are discussed, and simulation study based on a practical road network is given to illustrate the validity of the proposed method. Second, the topological structure optimization problem is formulated as a graph problem, while fulfilling random node-to-node communication demands. A new optimization method, called un-detour optimization, is proposed to optimize the topological structure based on the improved genetic algorithm. In addition, the approach is evaluated quantitatively by simulating community wireless sensor networks. The comparison results demonstrate that some significant performance advantages can be achieved by this approach. / In addition, two important techniques required to build the new surveillance system are discussed in this thesis. (1) the sensors to collect traffic information; (2) the communication network to transmit information among all sensors and vehicles. / In order to detect and track the moving objects, this thesis presents a creative background updating method, which can works effectively even for some complex circumstances. The image processing results show that this method can realize the segmentation of the moving objects. Due to the simple model and fast calculation speed, the method can satisfy the requirements of detecting and tracking traffic objects in real time and at a high speed. Additionally, the thesis designs a new kind of object detection and tracking algorithm based on the attributive combination of contour and color in order to deal with the occlusion problem to some extent. Some experiments have testified to the robustness and practicability of the proposed system. / Nowadays, with the rapid development of economics and societies, transportation is playing a very important role in the balanced running of social and economic systems. However, urban traffic problems such as traffic accidents and traffic congestions are becoming more and more serious in almost all large cities in the world. / This thesis is focused on a traffic surveillance system which collects and transmits real-time traffic information in a large city, which is one of the most important steps in solving the transportation problems above. Considering the drawbacks of current traffic surveillance system, a brand-new system with a distributed architecture is proposed based on the concept of sensor networks. Then, an intelligent sensor node using an embedded ARM chip and MCU is developed and software system is built up accordingly, including Linux operating system, hardware drivers, and so on. Finally, a simulation program proves the validity of the system. / Shi, Xi. / "September 2007." / Adviser: YangShong Xu. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4946. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 120-130). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Este trabalho enfoca a questão da segurança viária na cidade de Belém. Para a realização do trabalho, foi feito um diagnóstico sobre a gestão da segurança viária na cidade e um estudo dos acidentes de trânsito em dez pontos considerados pelas autoridades como os mais problemáticos, que incluiu a análise das causas dos acidentes através de auditorias de campo. Também são apresentadas algumas propostas para melhoria da gestão da segurança viária na cidade, bem como propostas específicas para redução dos acidentes nos locais estudados. As propostas genéricas para a melhoria da segurança viária em Belém são: campanhas educativas mais eficientes; melhoria da gestão da segurança do trânsito; aumento do número de fiscais de trânsito e melhoria do esquema de fiscalização; montagem de uma equipe permanente de técnicos com objetivo de identificar os pontos críticos, realizar auditorias de campo para identificar as causas dos acidentes e propor e implantar soluções para redução dos mesmos; etc. / This research focuses on the traffic safety problem in Belém city. For the accomplishment of the work, it was made a diagnosis remains to the traffic safety\'s management in the city and a study of the traffic accidents in ten points considered by the authorities as the most problematic, that it included the analysis of the accidents causes through field auditing. Also some proposals for improvement of the traffic safety\'s management in the city, as well as specific proposals for accidents reduction in the studied places. The generic proposals for the traffic safety\'s improvement in Belém are: more efficient educational campaigns; improvement of the traffic safety\'s management; increase of the number of traffic district attorney and improvement of the inspection plan; assembly of a permanent technicians team with goal of identifying the critical points, to accomplish field auditing in order to identify the accidents causes and, to propose and to establish solutions for reduction of the same ones; etc.

Este trabalho apresenta a técnica MDJ para avaliação de conflitos de tráfego em interseções de vias urbanas, idealizadas para as condições do trânsito observadas no Brasil. Para tanto, a técnica MDJ, além dos conflitos comuns de tráfego considerados nas técnicas estrangeiras, também considera como conflitos os seguintes fatos: desrespeito às regras de circulação, avanço do sinal vermelho, freada ou desvio de trajetória provocado por problema na via e dificuldade de manobra provocada por interferência visual (prejuízo da visibilidade devido ao meio ambiente). Para avaliação da validade da técnica MDJ, foram analisados quatro cruzamentos críticos em termos de acidentes na cidade de São Carlos - SP, com os conflitos observados comparados com os dados de acidentes de trânsito nos locais relativos ao período de um ano. A análise realizada mostrou uma correlação satisfatória entre os dados de conflitos e os dados de acidentes, o que sugere ser a técnica MDJ, em princípio, adequada para estudos de segurança viária em cruzamentos urbanos no Brasil. Contudo, é necessário uma maior quantidade de comparações conflitos/acidentes em outras situações (cidades e cruzamentos) para se concluir da adequabilidade do método para as condições brasileiras. / This work presents the MDJ technique for evaluation of contlicts of traffic in intersections of urban roads, idealised for the conditions of the traffic observed in Brazil. For that, the MDJ technique, besides the common conflicts of traffic considered in the foreign techniques, also considers as conflicts the following facts: disrespect to the rules of circulation, crossing the red light, braked or trajectory deviation provoked by problem in the road and manoeuvre difficulty provoked by visual interference (damage of the visibility due to the environment). For evaluation of the validity of MDJ technique, four critical crossings were analysed in terms of accidents in the city of São Carlos-SP, with the observed conflicts compared with the data of accidents of traffic in the relative places during a period of one year. Ths analysis showed a satisfactory correlation between the data of conflicts and the data of accidents, what suggests that the MDJ technique, in the beginning, ito be good for studies of road safety in urban crossings in Brazil. However, it is necessary a larger amount of comparisons conflicts/accidents in another situations (cities and crossings) to consider the suitability of the method for the Brazilian conditions.

Neste trabalho é apresentada a aplicação da Técnica Sueca de Análise de Conflitos de Tráfego em 5 (cinco) interseções críticas da cidade de São Carlos. Baseado nos resultados obtidos, são propostas ações simples e de baixo custo para aumentar a segurança viária nos locais estudados. Uma das propostas foi implementada tornando possível avaliar o desempenho do cruzamento após a implantação utilizando a Técnica Sueca de Análise de Conflitos de Tráfego. Esta implantação apresentou resultados bastante satisfatórios, proporcionando redução drástica no número e gravidade dos conflitos. A experiência na aplicação da Técnica Sueca de Análise de Conflitos de Tráfego em São Carlos mostra ser a mesma uma ferramenta bastante útil para análise da segurança viária em locais críticos, sobretudo proporcionando informações fundamentais na definição de ações para reduzir os conflitos e, consequentemente, os acidentes. / In this work we present the Application of the Swedish Technique of Traffic Conflict Analysis in 5 (five) critical intersections in the city of São Carlos. Based on the obtained results, simple and low-cost actions are proposed in order to increase the traffic safety in the studied places. One of the proposals has been put in practice enabling the evaluation of the crossing performance after having implanted the Swedish Technique of Traffic Conflict Analysis. This implantation has presented quite satisfactory results, providing drastic reduction both in number and seriousness of the conflicts. The experience in the Application of the Swedish Technique of Traffic Conflict Analysis shows it to be a very useful tool for the traffic safety analysis in critical places, overall providing essential information in the action definition to reduce the conflicts, and consequently the accidents.

The rapid growth of the Internet, in the last few years, has generated a need to enhance the existing IP networks in the areas of availability, dependability and scalability in order to provide a mission critical networking environment. In contemporary IP networks, data packets are routed as a function of the destination address and a single metric such as hop-count or delay. This approach tends to cause message traffic to converge onto the same link, which significantly increases congestion and leads to unbalanced network resource utilization. One solution to this problem is provided by Traffic Engineering (TE), which uses, bandwidth guaranteed, Explicitly Routed Label Switched Paths (ER-LSPs). Due to the dramatic increase in the backbone speeds, current research focuses more on traffic engineering with LSPs for clear control over the traffic distribution in the network. However, the growing popularity of the Internet is driving the Internet Service Providers to adapt new technologies in order to support multiple classes of applications with different characteristics and performance requirements. Multi-Protocol Label Switching (MPLS), which was proposed by the IETF provides essential facilities for traffic engineering and reliable QoS services for the Internet. MPLS networks provide the required flexibility for operators to manage their traffic with ER-LSPs. Even though conventional routing algorithms support the ER-LSP setup in MPLS networks, they are not efficient in link residual capacity information updates and limit resource utilization, which eventually leads to LSP failures and unbalanced network resource utilization. This thesis proposes a new architecture with a cluster based distributed routing algorithm to setup bandwidth guaranteed ER-LSPs in MPLS backbone networks. The proposed routing algorithm confines the route discovery region in order to reduce the routing overhead and computes all possible routes from ingress node to egress node. Based on LSP requirements and network load conditions, the egress node selects the most suitable path from the available paths in order to setup the LSP. This routing scheme optimizes network resource utilization by evenly distributing traffic throughout the network. The Resource Reservation Protocol (RSVP) works in conjunction with the routing protocol for resource reservation and label distribution along the LSP.