Após o fim da Segunda Guerra Mundial, teve início um processo de aumento da utilização dos automóveis nos grandes centros urbanos que modificou o desenho das cidades e o padrão de deslocamento nesses espaços. Uma das diversas consequências negativas da consolidação do automóvel como principal meio de transporte nas metrópoles foi o aumento do número de acidentes no trânsito, principalmente os que envolviam os usuários de transporte ativo – pedestres e ciclistas. A promoção dos modos de transporte não motorizados, como a bicicleta, é tida como ação complementar para reversão desse processo, porém, para tanto, é necessário melhorar a percepção de segurança sobre o modo cicloviário. A tomada de decisão por parte dos gestores do tráfego acerca das intervenções viárias que melhoram a segurança dos ciclistas carece de entendimento sobre os elementos que influenciam a ocorrência de acidentes envolvendo estes usuários. Desse modo, o trabalho desenvolvido nesta dissertação tem como objetivo a verificação da existência de relação entre os elementos urbanos construídos, os fatores socioeconômicos e outras possíveis fontes de risco com a frequência e severidade dos acidentes cicloviários na cidade de Porto Alegre O processo de investigação utilizou softwares de georreferenciamento para consolidar os dados coletados segundo as unidades de análise definidas. A frequência de acidentes foi modelada através de Modelo de Regressão Binomial Negativo e a severidade de acidentes foi modelada através de Modelo Logit Multinomial. O modelo de frequência de acidentes apresentou duas variáveis significativas. Em seguida, foi gerado um novo modelo de frequência de acidentes a partir da eliminação de possíveis fontes de discrepância dos dados. Os resultados indicaram que este segundo modelo estava melhor ajustado ao cenário estudado. O modelo de severidade de acidentes foi composto por 18 variáveis significativas. Por fim, os elementos que demonstraram maior prevalência sobre a acidentalidade de ciclistas foram a interação com automóveis, a presença de vias arteriais, a proximidade com áreas de interseção e o envolvimento de usuários vulneráveis (jovens e idosos em bicicletas) nos acidentes. / After the end of the World War II, many cities around the world have experienced an increase on car using which changed the way cities were planned and also mobility patterns. That process has generated some problems at urban areas like road accidents increasing, most of them related to active transport modes - pedestrians and cyclers. Non motorized transportation modes fomentation, for example cycling, emerges as an alternative to change this issue. However, before it happens, cyclers need to feel more safe on transit. Understanding the influence of the elements that affect cyclers's safety gives to decision makers and traffic managers a better possibility to make the right decisions on safety improvement. Thus, this thesis aims to verify the relationship between built environment, socialeconomic factors and other risk sources and frequency and severity of traffic crashes involving cyclists in Porto Alegre. By using GIS softwares, the collected data were consolidated according to the defined analysis units. Accident’s frequencies were modeled and the coefficients were estimated by using Negative Binomial Regression Model and the severity of accidents was modeled as a Multinomial Logit Model. The accident frequency model counted with two sginificant variables. Then, a new accident frequency model was estimated from the elimination of possible sources of data discrepancy. Results have shown that the second model fit better on the studied scenario. The accident severity model resulted in 18 significant variables. Finally, the elements that showed highest prevalences on cyclists safety were car interaction, presence of arterial roads, proximity to intersection areas and vulnerable cyclists users (young and old ones cycling) involvement on accidents.

Neste trabalho é avaliado o desempenho operacional de uma nova configuração idealizada para a operação de rotatórias de três pernas (prioridade para os veículos da via principal com semáforos próximos). Nesta avaliação é comparado o novo sistema de operação com outros dois usualmente empregados: (1) prioridade para os veículos que estão circulando na ilha central (rotatória convencional) e (2) prioridade para os veículos da via principal sem o emprego de semáforo, bem como, com base nos resultados das comparações realizadas, são estabelecidas as condições dos fluxos de tráfego em que é indicada uma ou outra configuração. Os valores obtidos nas simulações mostram, de forma inequívoca, o desempenho operacional superior da rotatória com prioridade para a via principal com semáforos próximos, adequadamente programados, no caso de fluxos altos. O emprego de semáforos próximos reduz significativamente o atraso na aproximação crítica e, em consequência, o tamanho da fila, como consequência do aumento expressivo da capacidade de tráfego da rotatória. Os resultados da simulação corroboram o que se pode observar nos sistemas implantados na cidade de Araraquara, onde a colocação de semáforos próximos de rotatórias de três pernas melhorou de forma significativa o desempenho operacional dos dispositivos, reduzindo o atraso crítico e o tamanho da fila crítica e aumentando a capacidade. O acompanhamento da acidentalidade nas rotatórias onde foram colocados semáforos próximos na cidade de Araraquara mostra uma redução dos acidentes graves de aproximadamente 90%. Uma explicação para essa redução pode ser devido ao aumento da paciência dos motoristas em esperar uma brecha maior para entrar na rotatória, pois sabem que, esporadicamente, há uma interrupção do fluxo na via principal. / In this study the operational performance is measured of a new idealized configuration for the operation in three-legged traffic circles (priority way for the vehicles from the main street with traffic lights nearby). This measured is compared the new operational system with two others usually systems: (1) priority for the circulating traffic (conventional roundabout) and (2) priority for vehicles from the main street without traffic lights. Also, based on the results from the comparisons, seek to establish what traffic flow conditions are better for a given configuration. The values obtained from the simulations demonstrate, clearly, the superior operational performance of the traffic circle with main road priority combined with properly programmed traffic lights nearby, in the case of high flows. The use of traffic lights reduces significantly the delay from the critical approach, and consequently, the queue length, as a consequence resulting on significant traffic capacity increase at the intersection. Simulation results validate what can be seen in Araraquara, where the installation of traffic lights near from the three-legged traffic circle improved significantly the operating performance of the devices, reducing the critical delay and critical queue size and increasing the effective capacity. Monitoring the accident rate in traffic circles where traffic lights nearby were placed in Araraquara shows a reduction of approximately 90% in serious accidents. An explanation of this reduction may be due to the increased of patience of drivers in wait for a larger gap to enter on the roundabout, because they know there will be an interruption on the main street, sporadically.

Traffic collisions cost Uganda millions of dollars each year. The purpose of this descriptive case study was to describe the strategies and processes needed to implement a road management system. Such a system would significantly reduce the fatalities and accidents in Uganda, improve the transportation within Kampala's business district, and increase business profitability. Three conceptual theories framed the research study: management theory, strategic management theory, and criminology theory. Using a snowball sampling strategy, data were collected from open-ended interviews, questionnaires, observations, and archived documents from 20 administrative participants in the government and organizational leaders involved in the transport operations and transport services in the Kampala business district in Uganda. Data were analyzed using 3 phases: (a) interpretational analysis, coding, and grouping segments; (b) structural analysis, consistency, and quality; and (c) reflective analysis, consequences, what, when, where, and how. Five themes or action requirements emerged from the data analysis: to improve transport operations and transport services profitability, reduce traffic jams and fatalities, provide sufficient driving training, maintain road infrastructure, and maintain traffic law enforcement. The findings and recommendations from this study may improve the profitability of businesses, reduce the traffic jams and fatalities, and improve the gross domestic product of Uganda, thereby contributing to positive social change.

La presente tesis tiene como objetivo establecer una alternativa de solución para mejorar la seguridad del peatón en la intersección Av. Los Héroes con Calle Antonio Buckingham en el distrito de San Juan de Miraflores. La investigación engloba 7 capítulos más las conclusiones, recomendaciones, bibliografía, anexos y planos. El primer, segundo y tercer capítulo abarcan generalidades, marco teórico y la descripción del software Vissim 9, respectivamente. En el cuarto capítulo se realizó un diagnóstico de la situación actual que permitió identificar las deficiencias que generan inseguridad al peatón en el sistema vial. De esta manera, se propusieron soluciones desde el punto de vista peatonal mediante el análisis de tránsito con la metodología del HCM 2010. Existen tres escenarios, el primero es la configuración actual de la vía, de la cual se hace el respectivo análisis vehicular y peatonal, en el segundo escenario se plantea una propuesta de medidas de gestión (semaforización, señalización y cambios geométricos) que funcionan como un sistema eficiente, coordinado y seguro. Finalmente, en el tercer escenario se desarrolla el análisis de la proyección futura de la propuesta. El quinto y sexto capítulo incluyen la propuesta detallada de infraestructura vial y señalización; y la modelación microscópica de la intersección en el software VISSIM 9, respectivamente. El séptimo capítulo desarrolla el análisis, evaluación y validación de la propuesta, esta última mediante juicio de expertos. Al finalizar la investigación se llega la conclusión de que las medidas de gestión adoptadas como solución a la problemática mejorará la intersección de forma efectiva si se implementan. / The objective of this thesis is to establish an alternative solution to improve pedestrian safety at the intersection Los Heroes Avenue with Antonio Buckingham Street in the district of San Juan de Miraflores. The research includes 7 chapters plus conclusions, recommendations, bibliography and annexes. The first, second and third chapters cover generalities, the theoretical framework and the description of the Vissim 9 software, respectively. In the fourth chapter, a diagnosis was made of the current situation that allowed identifying the deficiencies that generate insecurity for pedestrians in the road system. In this way, solutions were proposed from the pedestrian point of view through the traffic analysis with the HCM 2010 methodology. There are three scenarios, the first is the current configuration of the road, from which the respective vehicular and pedestrian analysis is made, in the second scenario, a proposal of management measures is proposed (traffic light, signaling and geometric changes) that function as an efficient, coordinated and secure system. Finally, in the third scenario, the analysis of the future projection of the proposal is developed. The fifth and sixth chapters include the detailed proposal of road infrastructure and signaling; and the microscopic modeling of the intersection in the VISSIM 9 software, respectively. The seventh chapter develops the analysis, evaluation and validation of the proposal, the latter through expert judgment. At the end of the investigation, the conclusion is reached that the management measures adopted as a solution to the problem will improve the intersection effectively if they are implemented. / Tesis

<p>Models based on micro-simulation of traffic flows have proven to be useful tools in the study of various traffic systems. Today, there is a wealth of traffic microsimulation models developed for freeway and urban street networks. The road mileage is however in many countries dominated by rural highways. Hence, there is a need for rural road traffic simulation models capable of assessing the performance of such road environments. This thesis introduces a versatile traffic micro-simulation model for the rural roads of today and of the future. The developed model system considers all common types of rural roads including effects of intersections and roundabouts on the main road traffic. The model is calibrated and validated through a simulation study comparing a two-lane highway to rural road designs with separated oncoming traffic lanes. A good general agreement between the simulation results and the field data is established.</p><p>The interest in road safety and the environmental impact of traffic is growing. Recent research has indicated that traffic simulation can be of use in these areas as well as in traditional capacity and level-of-service studies. In the road safety area more attention is turning towards active safety improving countermeasures designed to improve road safety by reducing the number of driver errors and the accident risks. One important example is Advanced Driver Assistance Systems (ADAS). The potential to use traffic simulation to evaluate the road safety effects of ADAS is investigated in the last part of this thesis. A car-following model for simulation of traffic including ADAS-equipped vehicles is proposed and the developed simulation framework is used to study important properties of a traffic simulation model to be used for safety evaluation of ADAS. Driver behavior for ADAS-equipped vehicles has usually not been considered in simulation studies including ADAS-equipped vehicles. The work in this thesis does however indicate that modeling of the behavior of drivers in ADAS-equipped vehicles is essential for reliable conclusions on the road safety effects of ADAS.</p> / Report code: LiU-Tek-Lic-2005:60.

<p>This thesis is devoted to understanding and counteracting the primary contributing factor in traffic crashes: inattention. Foremost, it demonstrates the fundamental importance of proactive gaze in the road centre area for action guidance in driving. Inattention is explained with regard to two visual functions (vision-for-action and vision-for-identification), three forms of attentional selection (action-driven-, stimulus-driven-, and goal-directed attention), and two forms of prediction influences (extrapolation-based- and decision-based prediction influences). In Study I an automated eye-movement analysis method was developed for a purpose-built eye-tracking sensor, and was successfully validated. This analysis method was further developed, and several new measures of gaze concentration to the road centre area were created. Study II demonstrated that a sharp decrease in the amount of road centre viewing time is accompanied by a dramatic spatial concentration towards the road centre area in returning gaze during visual tasks. During cognitive tasks, a spatial gaze concentration to road centre is also evident; however contrary to visual tasks, road centre viewing time is increased because the eyes are not directed towards an object within the vehicle. Study III found that gaze concentration measures are highly sensitive to driving task demands as well as to visual and auditory in-vehicle tasks. Gaze concentration to the road centre area was found as driving task complexity increased, as shown in differences between rural curved- and straight sections, between rural and motorway road types, and between simulator and field motorways. Further, when task duration was held constant and the in-vehicle visual task became more difficult, drivers looked less at the road centre area ahead, and looked at the display more often, for longer periods, and for more varied durations. In closing, it is shown how this knowledge can be applied to create in-vehicle attention support functions that counteract the effects of inattention.</p>

This thesis is devoted to understanding and counteracting the primary contributing factor in traffic crashes: inattention. Foremost, it demonstrates the fundamental importance of proactive gaze in the road centre area for action guidance in driving. Inattention is explained with regard to two visual functions (vision-for-action and vision-for-identification), three forms of attentional selection (action-driven-, stimulus-driven-, and goal-directed attention), and two forms of prediction influences (extrapolation-based- and decision-based prediction influences). In Study I an automated eye-movement analysis method was developed for a purpose-built eye-tracking sensor, and was successfully validated. This analysis method was further developed, and several new measures of gaze concentration to the road centre area were created. Study II demonstrated that a sharp decrease in the amount of road centre viewing time is accompanied by a dramatic spatial concentration towards the road centre area in returning gaze during visual tasks. During cognitive tasks, a spatial gaze concentration to road centre is also evident; however contrary to visual tasks, road centre viewing time is increased because the eyes are not directed towards an object within the vehicle. Study III found that gaze concentration measures are highly sensitive to driving task demands as well as to visual and auditory in-vehicle tasks. Gaze concentration to the road centre area was found as driving task complexity increased, as shown in differences between rural curved- and straight sections, between rural and motorway road types, and between simulator and field motorways. Further, when task duration was held constant and the in-vehicle visual task became more difficult, drivers looked less at the road centre area ahead, and looked at the display more often, for longer periods, and for more varied durations. In closing, it is shown how this knowledge can be applied to create in-vehicle attention support functions that counteract the effects of inattention.

In roadway projects, design exceptions are implemented when the project site consists of one or more substandard design elements. The objective of this thesis is to conduct an initial investigation for a monitoring program for the safety performance of design exceptions in Georgia. A total of 467 projects containing design exceptions were reported in Georgia from 1995 to 2011, and from this crash data for 179 projects from 2003 to 2008 were sampled. The crash data collected in this research pertains to all roadway segments within the projects and is not necessarily related to the design exceptions. Future efforts will be required to explore potential connections between the crash rates and design exceptions. The annual crash results generally revealed a high variability and randomness in the data. For this reason, the average 3-year crash frequencies before design exception approval date and after it were calculated to determine the safety performance for projects containing design exceptions. A method for determining expected results using the Highway Safety Manual (HSM) predictive method is also discussed. The findings will be used to guide future research on design exceptions and mitigation measures to improve roadway safety.

Da die menschliche Sehleistung bei geringer Beleuchtung stark vermindert ist, birgt die Teilnahme am nächtlichen Straßenverkehr besondere Gefahren. Sowohl Kraftfahrzeugführer als auch schwächere Verkehrsteilnehmer sind sich dieser Problematik offenbar nicht hinlänglich bewusst und verhalten sich häufig hochriskant. Dies hat, gemessen an der Exposition, eine überproportionale Häufigkeit und Schwere von Nachtunfällen zur Folge. Um dieser Situation zu begegnen, erscheinen neben konventionellen Präventionsmaßnahmen der Verkehrsüberwachung und -erziehung oder Eingriffen in die Verkehrsinfrastruktur auch neuartige fahrzeugtechnische Systeme geeignet. So wurden in den letzten Jahren Fahrerassistenzfunktionen entwickelt, welche mittels adaptiver Lichtsteuerung die Ausleuchtung des Verkehrsraumes verbessern sollen. Hierfür wird das lichttechnische Signalbild anderer Fahrzeuge mittels einer Kamera erfasst und die eigene Scheinwerferlichtverteilung so angepasst, dass die Straße maximal ausgeleuchtet wird, um die Hinderniserkennung zu verbessern und trotzdem gleichzeitig eine Blendung anderer Kraftfahrer zu vermeiden. Als zusätzlich integrierte Funktion kommt auch eine automatisierte Fernlichtschaltung zum Einsatz. Bislang war nicht belegt, ob diese sogenannten Adaptiven Frontbeleuchtungssysteme (AFS) in der Lage sind, tatsächlich zu einer Erhöhung der nächtlichen Verkehrssicherheit beizutragen. Ziel der vorliegenden Arbeit war es, Anforderungen zur Blendungsvermeidung beim Einsatz derartiger Assistenzfunktionen aufzustellen und die Wirksamkeit adaptierter Scheinwerferlichtverteilungen zu bewerten. Hierfür wurden entsprechende empirische Untersuchungen durchgeführt. So konnten in der ersten Studie Blendungsgrenzwerte ermittelt werden, welche sicherstellen sollen, dass andere Verkehrsteilnehmer nicht über das bislang übliche Maß hinaus durch die Scheinwerfer geblendet werden, wenn neuartige AFS zum Einsatz kommen. In einem weiteren Experiment wurde geprüft, ob unter Einhaltung dieser Grenzwerte eine nennenswerte Erhöhung der Erkennbarkeitsentfernungen für schlecht sichtbare Hindernisse auf der Straße erreichbar ist. Die letzte Studie beschäftigte sich mit der Frage, in welchem Umfang adaptierte Lichtverteilungen im realen Straßenverkehr zum Einsatz kämen, um deren mögliche Wirksamkeit besser beurteilen zu können. Parallel hierzu wurde auch das Fernlichtnutzungsverhalten der Probanden untersucht. Wie die durchgeführten Untersuchungen zeigen konnten, ergeben sich durch den Einsatz adaptierter Lichtverteilungen signifikante Verbesserungen bezüglich der Erkennbarkeit von Hindernissen gegenüber konventioneller Kraftfahrzeugbeleuchtung in teils beträchtlichem Ausmaß. Außerdem konnte ermittelt werden, dass adaptierte Scheinwerferlichtverteilungen im realen Straßenverkehr in erheblichem Umfang zum Tragen kämen. Aufgrund der viel zu geringen Fernlichtnutzung könnten Kraftfahrer auch besonders stark von der automatisierten Fernlichtschaltung profitieren. Damit kann davon ausgegangen werden, dass neuartige AFS tatsächlich überaus geeignet sind, nächtliche Kollisionen von Kraftfahrzeugen mit unbeleuchteten schwächeren Verkehrsteilnehmern oder Wild zu vermeiden. Trotz dieser Einschätzung sind die letztlich zu erwartenden positiven Auswirkungen auf die Verkehrssicherheit womöglich eher gering, wenn es nicht gelingt, alle Verkehrsteilnehmer für die Gefahren des nächtlichen Straßenverkehrs zu sensibilisieren. Zudem können Adaptive Frontbeleuchtungssysteme selbstverständlich nicht allen Ursachen nächtlicher Kollisionen mit Hindernissen auf der Straße wirkungsvoll begegnen. / Since the human visual performance is substantially degraded under low illumination levels participating in nighttime traffic is particularly dangerous. Drivers as well as vulnerable road users are not sufficiently aware of this and therefore expose themselves to severe risks. Compared to overall exposure, a disproportionately high number of severe injuries and fatalities occur in nighttime traffic. Besides conventional approaches such as enforcement, education, and infrastructural measures, new automotive systems promise additional gains in road safety. Recently, Adaptive Frontlighting Systems (AFS) have been developed that are meant to improve road illumination in front of the car. Therefore, other lit vehicles are detected by a camera, which allows adapting the beam pattern according to the traffi c situation. The maximum of illumination is directed at the road to enhance object detection while omitting oncoming traffic to prevent glare to other drivers. This functionality also includes high beam automation. Up to now it has not been convincingly substantiated if so-called AFS are actually capable of increasing road safety. Thus, the aim of this thesis was to set up system specifications for the prevention of glare and to assess the impact of adapted light distributions by conducting adequate empirical studies. The first study identified illuminance thresholds in order to assure that other drivers will not suffer from glare when AFS are applied that are beyond present levels caused by regular low beams. The second experiment examined if the adaptation of beam patters within these identified limits improves detection distances for unlit obstacles on the road. The last study examined the extent of AFS’ applicability in real nighttime traffic, to better estimate the possible efficacy of such systems. The high beam usage behavior of the test subjects was also analyzed within this driving study. Adapted beam patterns turned out to significantly improve obstacle detection in comparison to conventional low beams. It was found that adaptive lighting functions could cover a substantial part of time driven in rural areas. Besides, high beam automation could dramatically increase high beam usage since drivers mostly fail to maintain manual switching. Taking these findings into consideration AFS seem to be suited to prevent collisions with unlit obstacles during nighttime driving. However, their impact on road safety could remain marginal unless road users are sensitized for the dangers of participating in traffic during darkness. Moreover, AFS cannot counteract all causes of nighttime collisions.

<p>The thesis aims at developing new, alternative approaches and methods based on suggestions and ideas originating from moral philosophy and philosophical decision theory. More precisely, the thesis aims at investigating the rationality of transport policy decisions, including goal-setting and performance evaluation.</p><p>Paper I discusses rationality in road safety policy. Problematic features are identified and discussed. The paper argues that the Swedish road safety goal is rational, since it is action-guiding and achievement-inducing. This follows by observing that the goal satisfies the criteria of <em>precision,</em> <em>evaluability, approachability, </em>and <em>motivity</em>. The paper states that previous accusations of irrationality have been unnecessarily imprecise, since no reference is made to independently developed criteria of rational goal-setting.</p><p>Paper II discusses the Swedish transport policy goals, and the role of social welfare in rational policy decisions. Goals often come into conflict and trade-offs must be rationally and consistently managed. Policy decisions are outcomes of political processes. In the case of policy goals and decisions, the agent is society. This introduces the problematic concept of social welfare, which itself is an ambiguous goal with many meanings. Whether a decision is rational or not depends on whose perspective one takes on – that of society as a whole or that of the actual decision makers.</p><p>Paper III aims at investigating six different procedures for resolving goal conflicts: weighted average, lexicographic preference, conditional lexicographic preference, absolute restriction, generalised prioritarianism, and partial comparability. Criteria for selection, according to the respective procedures, are formulated and summarised in a table. The six procedures are contrasted with respect to their tendency to rule out possible sets of alternatives as being not choiceworthy.</p>