On the importance of driver models for the development and assessment of active safety: A new collision warning system to make overtaking cyclists safer

The total number of road crashes in Europe is decreasing, but the number of crashes involving cyclists is not decreasing at the same rate. When cars and bicycles share the same lane, cars typically need to overtake them, creating dangerous conflicts—especially on rural roads, where cars travel much faster than cyclists. In order to protect cyclists, advanced driver assistance systems (ADAS) are being developed and introduced to the market. One of them is a forward collision warning (FCW) system that helps prevent rear-end crashes by identifying and alerting drivers of threats ahead. The objective of this study is to assess the relative safety benefit of a behaviour-based (BB) FCW system that protects cyclists in a car–to–cyclist overtaking scenario. Virtual safety assessments were performed on crashes derived from naturalistic driving data. A series of driver response models was used to simulate different driver reactions to the warning. Crash frequency in conjunction with an injury risk model was used to estimate the risk of cyclist injury and fatality. The virtual safety assessment estimated that, compared to no FCW, the BB FCW could reduce cyclists’ fatalities by 53–96% and serious injuries by 43–94%, depending on the driver response model. The shorter the driver’s reaction time and the larger the driver’s deceleration, the greater the benefits of the FCW. The BB FCW also proved to be more effective than a reference FCW based on the Euro NCAP standard test protocol. The findings of this study demonstrate the BB FCW’s great potential to avoid crashes and reduce injuries in car–to–cyclist overtaking scenarios, even when the driver response model did not exceed a comfortable rate of deceleration. The results suggest that a driver behaviour model integrated into ADAS collision threat algorithms can provide substantial safety benefits

Collision avoidance algorithm for intelligent vehicles using ITS-G5

Dissertação para obtenção do Grau de Mestre em Engenharia Informática e de ComputadoresDada a importância de melhorar a segurança rodoviária, é extremamente importante a criação de mecanismos que auxiliem a redução do número de acidentes rodoviários. Posto isto, esta tese visa o desenvolvimento de um algoritmo para alerta de colisões veiculares, capaz de apoiar o condutor na sua tarefa. O algoritmo proposta, inicialmente utiliza ITS-G5 como canal de comunicação entre veículos. No entanto, dada a necessidade de disponibilizar a aplicação à maioria dos utilizadores, apresenta-se também uma solução para smartphone que permite a utilização da mesma a utilizadores que não tenham acesso a uma OBU ITS-G5. Neste trabalho, o algoritmo de previsão de colisão foi definido e implementado e, para dar suporte à aplicação móvel, foi desenvolvido um ambiente híbrido entre ITS-G5 e redes celulares. A troca de informação é feita utilizando mensagens CAM. Dado a importância da latência no desempenho da aplicação, foram realizadas medições de latência para validar a solução proposta. Em geral, os melhores resultados foram obtidos aquando da utilização do 4G, obtendo uma latência média de 42 ms. O uso da rede 5G não alcançou as expectativas, pois esperavam-se menores latências que o 4G, mas apenas se verificaram latências similares e com maior instabilidade. Ao testar o algoritmo desenvolvido, foi utilizado um Digital Twin para auxiliar os testes à solução permitindo a criação de situações específicas de alto risco. Posto isto, a sua utilização foi útil para testar uma situação constante de mensagens recebidas com latência elevada originando uma situação em que a aplicação assume um cenário distinto da realidade que impede a deteção da colisão, quando a mesma existe (falso negativo).Given the importance of improving road safety, it is crucial to create mechanisms that reduce road accidents. Therefore, this thesis aims the development of a collision warning algorithm capable of supporting the drivers’ tasks by alerting them to possible collisions. The algorithm proposed, initially uses ITS-G5 as a communication channel between vehicles. However, given the need to provide the application to most users, a smartphone application is also presented, making this solution accessible to users that don’t have access to an ITS-G5 OBU. In this work, a collision warning algorithm was defined and implemented and, to support the smartphone application, a hybrid environment between ITS-G5 and cellular network was developed. Information is exchanged among players using CAM messages. Given the role that latency plays in the performance of this kind of application, latency measurements were performed to validate the proposed framework. In general, the best results were obtained when using 4G, obtaining an average of 42 ms in latency. The usage of the 5G network didn’t meet the expectations since it promises lower latencies than 4G, but similar latencies and greater instability have been observed at this stage. When testing the developed application, a digital twin was used to assist the algorithm tests allowing the creation of specific dangerous situations. Therefore, the digital twin was used to test a specific scenario of constant high latency messages creating a false negative situation, where a collision would be detected if latency was lower/admissible.N/

Maniobrabilidad de vehículos de competición

[ES] El siguiente proyecto aborda de forma detallada la dinamica vehicular de coches de competicion y como afecta esta a la maniobrabilidad. La dinamica es uno de los aspectos mas importantes a tener en cuenta para el diseño de vehiculos de produccion, y mas aun, debido a la naturaleza competitiva y el alto ritmo de evolucion, en los vehiculos de competicion. Se comienza desarrollando un estudio sobre el comportamiento de los neumaticos, analizando las fuerzas que actuan sobre ellos y las distintas variables a tener en cuenta. A continuacion, nos encontramos con un capitulo en el que se explica la propia dinamica del vehiculo al completo, analizando las respuestas del vehiculo en estado estacionario y en estado transitorio. El siguiente capitulo trata sobre el frenado, en el que se indagan las formulas fundamentales para su entendimiento y algunos de los sistemas que se utilizan en la alta competicion. Siguiendo con la tematica, el apartado cinco es un estudio sobre la direccion y las geometrias utilizadas para optimizar el rendimiento. Para finalizar, se estudian las tecnicas de conduccion y los posibles reglajes que ayudan a bajar el tiempo por vuelta.[EN] The following project deals in detail with the vehicle dynamics of racing cars and how it affects handling. Dynamics is one of the most important aspects to be taken into account in the design of production vehicles, and even more so, due to the competitive nature and the high rate of evolution, in racing vehicles. We begin by developing a study on the behaviour of tyres, analysing the forces acting on them and the different variables to be taken into account. This is followed by a chapter in which the dynamics of the vehicle itself is explained in full, analysing the responses of the vehicle in steady and transient states. The next chapter deals with braking, in which the fundamental formulas for its understanding and some of the systems used in high competition are investigated. Continuing the theme, section five is a study of steering and the geometries used to optimise performance. Finally, driving techniques and possible settings to help lower lap times are examined

Mobility And Safety Evaluation Of Integrated Dynamic Merge And Speed Control Strategies In Work Zones

In recent years, there has been a considerable increase in the amount of construction work on the U.S. national highways. Most of the work undertaken is the reconstruction and rehabilitation of the existing transportation networks. Work zones in the United States are likely to increase in number, duration and length due to emphasis on repair and highway reconstruction as a significant portion of all federal-aid highway funds are now geared toward highway rehabilitation. The challenge of mobility is particularly acute in work zone areas as road repair and construction intensifies traffic issues and concentrates them in specific locations and at specific times. Due to the capacity drop, which is the result of lane closure in work zone area, congestion will occur with a high traffic demand. The congestion increases number and severity of traffic conflicts which raise the potential for accidents; furthermore traffic operational properties of roadway in work zone area become worse. Intelligent Transportation System (ITS) technologies have been developed and are being deployed to improve the safety and mobility of traffic in and around work zones. In several states in the US, the use of Dynamic Merge Controls also known as Dynamic Lane Merge (DLM) system has been initiated to enhance traffic safety and to improve traffic flow in work zone areas. The DLM usually takes two forms; dynamic iii early merge and dynamic late merge. The use of variable speed limit (VSL) systems at work zones is also one of those measures. VSL systems improve safety by helping the driver in determining the maximum speed that drivers should travel. Besides adding improvement to safety, they are also expected to improve mobility at the work zones. The main goal of this study is to evaluate the safety and operational effectiveness of the dynamic merge systems i.e. the dynamic early lane merge and dynamic late lane merge, in the presence of VSL system. More specifically, the VISSIM model is utilized to simulate a twoto-one lane configuration when one out of the two lanes in the work zone is closed for traffic. Six different scenarios were adopted to assess the effectiveness of these scenarios under different traffic demand volumes and different drivers‟ compliance rates to the messages displayed by the systems. These scenarios are; Work Zone without VSL and without SDLMS or the current Motorist Awareness System (MAS) Work Zone with VSL and without SDLMS Work Zone with VSL and Early SDLMS Work Zone with VSL and Late SDLMS Work Zone with early SDLMS and without VSL Work Zone with late SDLMS and without VSL iv An already calibrated and validated VISSIM model for Simplified Dynamic Lane Merge System (SDLMS) in accordance with the real life work zone was modified with a VSL through Vehicle Actuated Programming (VAP) code. Three different logics were coded each for VSL alone, early SDLMS+VSL and late SDLMS+VSL. All these logics were fine tuned with several test runs before finalizing it for the final simulation. It is found through the simulation of above mentioned scenarios that for low and medium volume levels (V0500, V1000 and V1500), there is no significant difference between the Maintenance of Traffic (MOT) plans for mean throughputs. However, for higher volume levels (V2000 and V2500), late SDLMS with and without VSL produced higher mean throughputs for all compliance rates and truck percentages except when the demand volume was 2,500 vph and compliance of 60%, where it produces the significantly lower mean throughputs. In terms of travel time through the work zone, results indicated that there is no significant difference between MOT types for demand levels of V0500 and V1000 when compliance is 40% or less but for compliance of 60% and more, only demand volume level that is not significantly different from other MOT types is V0500. This study revealed that VSL increases travel time through the work zone. This might be due to non-compliant vehicles that follow the compliant vehicle v ahead unless they find a sufficient gap in adjacent lane to pass the compliant vehicle. It is also found out that VSL makes the system safer at higher volumes (2,000 vph and 2,500 vph). This was observed through safety surrogate measures selected for this study. Another outcome of this study is that the addition of VSL to the dynamic merge systems helps in improving the overall safety of the system by lowering speed variances and deceleration means of the vehicles travelling through the work zone. The passage of traffic through the work zone is made safer when a speed control is integrated to a dynamic merge system. It can be inferred from the simulation results that integrated SDLMS and VSL systems have better performance in terms of traffic mobility and safety than existing individual controls and also show that the integrated SDLMS and VSL system has more potential than each individual systems

Safety impact of connected and autonomous vehicles on motorways: a traffic microsimulation study

Connected and Autonomous Vehicles (CAVs) promise to improve road safety greatly. Despite the numerous CAV trials around the globe, their benefit has yet to be proven using real-world data. The lack of real-world CAV data has shifted the focus of the research community from traditional safety impact assessment methods to traffic microsimulation in order to evaluate their impacts. However, a plethora of operational, tactical and strategic challenges arising from the implementation of CAV technology remain unaddressed. This thesis presents an innovative and integrated CAV traffic microsimulation framework that aims to cover the aforementioned shortcomings.A new CAV control algorithm is developed in C++ programming language containing a longitudinal and lateral control algorithm that for the first time takes into consideration sensor error and vehicle platoon formulation of various sizes. A route-based decision-making algorithm for CAVs is also developed. The algorithm is applied to a simulated network of the M1 motorway in the United Kingdom which is calibrated and validated using instrumented vehicle data and inductive loop detector data. Multiple CAV market penetration rate, platoon size and sensor error rate scenarios are formulated and evaluated. Safety evaluation is conducted using traffic conflicts as a safety surrogate measure which is a function of time-to-collision and post encroachment time. The results reveal significant safety benefit (i.e. 10-94% reduction of traffic conflicts) as CAV market penetration increases from 0% to 100%; however, it is underlined that special focus should be given in the motorway merging and diverging areas where CAVs seem to face the most challenges. Additionally, it is proven that if the correct CAV platoon size is implemented at the appropriate point in time, greater safety benefits may be achieved. Otherwise, safety might deteriorate. However, sensor error does not affect traffic conflicts for the studied network. These results could provide valuable insights to policy makers regarding the reconfiguration of existing infrastructure to accommodate CAVs, the trustworthiness of existing CAV equipment and the optimal platoon size that should be enforced according to the market penetration rate.Finally, in order to forecast the conflict reduction for any given market penetration rate and understand the underlying factors behind traffic conflicts in a traffic microsimulation environment in-depth, a hierarchical spatial Bayesian negative binomial regression model is developed, based on the simulated CAV data. The results exhibit that besides CAV market penetration rate, speed variance across lanes significantly affects the production of simulated conflicts. As speed variance increases, the safety benefit decreases. These results emphasize the importance of speed homogeneity between lanes in a motorway as well as the increased risk in the motorway merging/diverging areas.</div

An operational research-based integrated approach for mass evacuation planning of a city

Large-scale disasters are constantly occurring around the world, and in many cases evacuation of regions of city is needed. ‘Operational Research/Management Science’ (OR/MS) has been widely used in emergency planning for over five decades. Warning dissemination, evacuee transportation and shelter management are three ‘Evacuation Support Functions’ (ESF) generic to many hazards. This thesis has adopted a case study approach to illustrate the importance of integrated approach of evacuation planning and particularly the role of OR/MS models. In the warning dissemination phase, uncertainty in the household’s behaviour as ‘warning informants’ has been investigated along with uncertainties in the warning system. An agentbased model (ABM) was developed for ESF-1 with households as agents and ‘warning informants’ behaviour as the agent behaviour. The model was used to study warning dissemination effectiveness under various conditions of the official channel. In the transportation phase, uncertainties in the household’s behaviour such as departure time (a function of ESF-1), means of transport and destination have been. Households could evacuate as pedestrians, using car or evacuation buses. An ABM was developed to study the evacuation performance (measured in evacuation travel time). In this thesis, a holistic approach for planning the public evacuation shelters called ‘Shelter Information Management System’ (SIMS) has been developed. A generic allocation framework of was developed to available shelter capacity to the shelter demand by considering the evacuation travel time. This was formulated using integer programming. In the sheltering phase, the uncertainty in household shelter choices (either nearest/allocated/convenient) has been studied for its impact on allocation policies using sensitivity analyses. Using analyses from the models and detailed examination of household states from ‘warning to safety’, it was found that the three ESFs though sequential in time, however have lot of interdependencies from the perspective of evacuation planning. This thesis has illustrated an OR/MS based integrated approach including and beyond single ESF preparedness. The developed approach will help in understanding the inter-linkages of the three evacuation phases and preparing a multi-agency-based evacuation planning evacuatio

Vehicle and Traffic Safety

The book is devoted to contemporary issues regarding the safety of motor vehicles and road traffic. It presents the achievements of scientists, specialists, and industry representatives in the following selected areas of road transport safety and automotive engineering: active and passive vehicle safety, vehicle dynamics and stability, testing of vehicles (and their assemblies), including electric cars as well as autonomous vehicles. Selected issues from the area of accident analysis and reconstruction are discussed. The impact on road safety of aspects such as traffic control systems, road infrastructure, and human factors is also considered