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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Understanding the interaction between cyclists and automated vehicles: Results from a cycling simulator study

Mohammadi, Ali, Piccinini, Giulio B., Dozza, Marco 19 December 2022 (has links)
Cycling as an active mode of transport is increasing across all Europe [1]. Multiple benefits are coming from cycling both for the single user and the society as a whole. With increasing cycling, we expect more conflicts to happen between cyclists and vehicles, as it is also shown by the increasing cyclists' share of fatalities, contrary to the passenger cars' share [2]. Understanding cyclists' behavioral patterns can help automated vehicles (AVs) to predict cyclist's behavior, and then behave safely and comfortably when they encounter them. As a result, developing reliable predictive models of cyclist behavior will help AVs to interact safely with cyclists.
22

V2X Intention Sharing for E-bikes and E-scooters : Design and implementation of a vehicular network protocol for Vulnerable Road Users intention sharing.

Elfing, Johan, Pålsson, Joel January 2024 (has links)
Despite a steady decrease in fatality rates across European nations,Vulnerable Road User (VRU) continue to face significant risks in traffic incidents. Pedestrians, cyclists, and motorcyclists make up the majority of fatalities. Vision Zero sets a global standard for road safety,and its implementation complements broader European Union (EU)initiatives in prioritizing a zero-tolerance stance on road fatalities.This thesis underscores the transformative potential of VehicularAd hoc Networks (VANETs) by introducing a protocol to enhance roadsafety through intention sharing, particularly for micro-mobility vehicles such as E-bikes and E-scooters. By integrating this protocolwith Vehicle-to-Anything (V2X) technology, this thesis aims to redefine VRUs’ role in traffic safety from passive to active participants. Theprotocol aims to complement the quality of information and improving energy efficiency while maintaining safety metrics for cooperativetransportation systems. We achieved this by transmitting a reservedarea where the rider intends to be in the near future.Results from simulations demonstrate the efficacy of intention sharing in improving message reliability and efficiency compared to intention detection methods.While preliminary results show promise, further research is necessary to validate real-world applicability fully. Nonetheless, this thesiscontributes to the ongoing efforts to achieve Vision Zero by harnessing technological innovations to protect VRUs and create safer roadenvironments. / Trots en minskning av antalet dödsolyckor i europeiska länder fortsätter oskyddade trafikanter (VRU:er) att möta risker i trafiken. Fotgängare, cyklister och motorcyklister utgör majoriteten av dödsfall. Nollvisionen sätter en global standard för trafiksäkerhet, och dess implementering kompletterar bredare EU-initiativ som prioriterar nolltolerans mot dödsfall i trafiken. Denna avhandling understryker den transformativa potentialen hos Fordons ad-hoc-nätverk (VANETs) genom att introducera ett protokoll för att förbättra trafiksäkerheten genom delning av avsikter, särskilt för mikromobilitetsfordon såsom elcyklar och elsparkcyklar. Genom att integrera detta protokoll med Fordon till allt (V2X)-teknologi strävar detta arbete mot att omdefiniera VRU:ers roll i trafiksäkerhet från passiva till aktiva deltagare. Protokollet fungerar som så att den skickar meddelanden för VRU:ers intentioner till de andra deltagarna inom nätverket. Dessa meddelanden innehåller de framtida förutsägbara positionerna av VRU:n. Dessa positioner är sedan transformerade till en reserverad ellips där VRU:n kan tänkas befinna sig i framtiden.  Resultat från simuleringar visar effektiviteten i metoder som genom att dela avsikter förbättrar meddelandens pålitlighet och effektivitet i jämförelse med metoder som istället försöker detektera avsikter, vilket banar väg för säkrare transportsystem.  Det visade sig att tillförlitligheten bland meddelanden med intentioner var högre, störst skillnad var inom 100 meter från avsändaren. I denna grupp hade detekteringsmetoden en förlust av meddelanden på ungefär 20%, medans intentionsdelning endast hade en förlust på 5%. Dessutom var meddelandestorleken betydligt mindre, en minsking på 64%. De preliminära resultaten ser lovande ut, men vidare forskning är nödvändig för att fullt utvärdera den verkliga tillämpbarheten. Denna masteruppsats bidrar till den pågående eftersträvan att uppnå nollvisionen genom att utnyttja teknologiska innovationer för att skydda VRU:er genom samarbete och att skapa en säkrare trafikmiljö. Dessa resultat har potential att påverka standardiseringen på europeisk nivå och bana väg för framtidens mobilitet. / Trafikverket Skyltfonden 2023/104170
23

Zvyšování bezpečnosti v dopravě s ohledem na oceňování lidského života / Quantification of expenses in case of human death due to traffic accident and finding ways how to prevent them

Slánský, Josef January 2011 (has links)
This diploma thesis examines the issue of acceptability of a particular transportation project. It is objective is to capture the expenses which arise from a traffic accident. on this basis the goal is to express all expenses of the human death and to compare them with the specific transportation project. In addition to this, different means of accident prevention are to be figured out within the support of public safety. The whole thesis is split into four parts. The first part describes the accidents on Czech roads. The second part deals with the specific expression methodology of the human death. The third shows the real transportation project and the last section evaluates if the expenditure on the implementation of particular project exceed the expenses caused by the accident.
24

Konflikter på gång och cykelbana. : Ett skadepreventivt perspektiv. / Conflicts on pedestrian and bicyclepaths : an injury prevention perspective

Pettersson, Marie January 2010 (has links)
Att vistas på gång- och cykelbanor kan vara en situation som upplevs som otrygg av de oskyddade trafikanterna som delar på detta utrymme. Samexistens och hänsyn till medtrafikanter är av vikt för att minska konflikter och skador som uppstår i denna miljö. En anledning till konflikter mellan fotgängare och cyklister är den höga hastigheten som cyklister kan färdas i. Denna hastighet skapar otrygghet bland fotgängare samt hos de cyklister som färdas i ett långsammare tempo. Otryggheten, beteende hos de båda trafikantgrupperna samt hastigheten leder i vissa fall till konflikter med kollisioner och personskador som följd. Att separera gång- och cykeltrafiken minskar till viss del konflikterna mellan dessa två grupper, men konflikten mellan cyklister som färdas fort och de cyklister som färdas långsamt kvarstår samt att otryggheten till viss del kvarstår hos fotgängarna, speciellt i de fall separeringen enbart skett med färgmarkering. Andra orsaker till otrygghet och konflikter inom och mellan dessa grupper kan bland annat vara ljus och mörkerförhållanden, vägens underlag, tekniska fel på cykeln samt beteende hos trafikanterna. Fotgängare och cyklister drabbas hårt vid en olycka även med en annan oskyddad trafikant. Den upplevda känslan av otrygghet är större än den faktiska risken för att en olycka faktiskt skall inträffa. Kollisioner mellan fotgängare och cyklister på gång och cykelbanor är inget stort problem, statistiskt sett, men grundat på den upplevda oron och brist på trygghet i denna miljö får problemet större proportioner än det statistiska underlaget påvisar / Using the footpaths and cyclelanes may be a situation that is perceived as unsafe by the vulnerable road users who share this space. Coexisting and consideration for other road users is important to reduce conflicts and damages arising in this environment. One reason for conflicts between pedestrians and cyclists are the high speed at which cyclists can travel in. This speed creates insecurity among pedestrians and cyclists that chooses to move in a slower pace. Insecurity, behavior of the road user and the speed of the cyclist results in certain cases to conflicts with collisions and injuries as a result. Separating pedestrian and bicycletraffic decreases part of the conflicts between these two groups, but the conflict between cyclists who are traveling at high speed and the cyclists are traveling at a slow pace, persist and insecurity to some degree remains with the pedestrian, especially in cases separation occurred only with separation through a coloured centerline. Other causes of insecurity in a traffic environment and conflict within and between these groups may include how the roads are lit during the dark hours, darkness and sunflares, road surface, technical failure of the cycle and behavior of road users. Pedestrians and cyclists receive severe injuries even in an accident with another unprotected road user. The perceived sense of insecurity is greater than the actual risk of an accident actually occurring. Collisions of pedestrians and cyclists on footpaths and cyclelanes is rarely a problem, statistically, but based on the perceived fears, insecurity and lack of security in this environment, the problem may be of greater proportions than the statistical data reveals.
25

Urban congestion charging : road pricing as a traffic reduction measure / W. Heyns

Heyns, Werner January 2005 (has links)
Urban traffic congestion is recognised as a major problem by most people in world cities. However, the implementation of congestion reducing measures on a wide scale eludes most world cities suffering from traffic congestion, as many oppose the notion of road pricing and despite economists and transportation professionals having advocated its benefits for a number of decades. The effects of road pricing have attracted considerable attention from researchers examining its effects, as it is thought to hold the key in understanding and overcoming some inherent obstacles to implementation. Unfortunately, many of the attempts consider the effects in isolation and with hypothetical, idealised and analytical tools, sometimes loosing sight of the complexities of the problem. This research empirically investigates the effects of road pricing in London, and identifies factors, which may prove to sustain it as a traffic reduction instrument. The results indicate that an integrated approach has to be developed and implemented, based upon the recognition of local perceptions, concerns, aspirations and locally acceptable solutions, if the acceptance of road pricing is to be improved. The key to dealing with the effects of road pricing, is to encourage a concerted effort by various stakeholders developing strategies considering a range of differing initiatives, coordinating and managing them in the realm of the political-economic context in which they exist. / Thesis (M.Art. et Scien. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2005.
26

Urban congestion charging : road pricing as a traffic reduction measure / W. Heyns

Heyns, Werner January 2005 (has links)
Urban traffic congestion is recognised as a major problem by most people in world cities. However, the implementation of congestion reducing measures on a wide scale eludes most world cities suffering from traffic congestion, as many oppose the notion of road pricing and despite economists and transportation professionals having advocated its benefits for a number of decades. The effects of road pricing have attracted considerable attention from researchers examining its effects, as it is thought to hold the key in understanding and overcoming some inherent obstacles to implementation. Unfortunately, many of the attempts consider the effects in isolation and with hypothetical, idealised and analytical tools, sometimes loosing sight of the complexities of the problem. This research empirically investigates the effects of road pricing in London, and identifies factors, which may prove to sustain it as a traffic reduction instrument. The results indicate that an integrated approach has to be developed and implemented, based upon the recognition of local perceptions, concerns, aspirations and locally acceptable solutions, if the acceptance of road pricing is to be improved. The key to dealing with the effects of road pricing, is to encourage a concerted effort by various stakeholders developing strategies considering a range of differing initiatives, coordinating and managing them in the realm of the political-economic context in which they exist. / Thesis (M.Art. et Scien. (Town and Regional Planning))--North-West University, Potchefstroom Campus, 2005.
27

Understanding Boundary Conditions for Brain Injury Prediction : Finite Element Analysis of Vulnerable Road Users

S. Alvarez, Victor January 2017 (has links)
Vulnerable road users (VRUs) are overrepresented in the statistics on severe and deadly injuries in traffic accidents, most commonly involving the head. The finite element (FE) method presents the possibility to model complex interactions between the human body and vehicles in order to better understand the injury mechanisms. While the rapid development of computer capacity has allowed for increasingly detailed FE-models, there is always a benefit of reducing the studied problem. Due to its material properties, the brain is more sensitive to rotational motion than to purely linear, resulting in complex injury causation. When studying brain injuries caused by a direct impact to the head, simulations using an isolated head model significantly increases efficiency compared to using a complete human body model. Also evaluation of head protective systems uses isolated mechanical head representations. It is not, however, established the extent to which the boundary conditions of the head determine the outcome of brain injuries. FE models of both the entire human body and the isolated head were used in this thesis to study the effect of the body, as well as active neck muscle tension, on brain injury outcome in VRU accidents. A pediatric neck model was also developed to enable the study of age-specific effects. A vehicle windscreen model was developed to evaluate the necessity of capturing the failure deformation during pedestrian head impacts. It was shown that the influence of the neck and body on brain injury prediction is greater in longer duration impacts, such as pedestrian head-to-windscreen impacts with an average difference of 21%. In accidents with shorter duration impacts, such as head-to-ground bicycle accidents, the average influence was between 3-12%. The influence did not consistently increase or limit the severity, and was dependent on the degree of rotation induced by the impact, as well as the mode of deformation induced in the neck. It was also shown that the predicted brain injury severity is dependent on capturing the large deformations of fractured windscreen, with the greatest effect near the windscreen frame. The pediatric neck model showed a large effect of age-dependent anatomical changes on inertial head loading, making it a promising tool to study the age-dependent effects in VRU accidents. / <p>QC 20171013</p>
28

What externally presented information do VRUs require when interacting with fully Automated Road Transport Systems in shared space?

Merat, Natasha, Louw, Tyron, Madigan, Ruth, Wilbrink, Marc, Schieben, Anna 30 September 2020 (has links)
As the desire for deploying automated (“driverless”) vehicles increases, there is a need to understand how they might communicate with other road users in a mixed traffic, urban, setting. In the absence of an active and responsible human controller in the driving seat, who might currently communicate with other road users in uncertain/conflicting situations, in the future, understanding a driverless car’s behaviour and intentions will need to be relayed via easily comprehensible, intuitive and universally intelligible means, perhaps presented externally via new vehicle interfaces. This paper reports on the results of a questionnaire-based study, delivered to 664 participants, recruited during live demonstrations of an Automated Road Transport Systems (ARTS; SAE Level 4), in three European cities. The questionnaire sought the views of pedestrians and cyclists, focussing on whether respondents felt safe interacting with ARTS in shared space, and also what externally presented travel behaviour information from the ARTS was important to them. Results showed that most pedestrians felt safer when the ARTS were travelling in designated lanes, rather than in shared space, and the majority believed they had priority over the ARTS, in the absence of such infrastructure. Regardless of lane demarcations, all respondents highlighted the importance of receiving some communication information about the behaviour of the ARTS, with acknowledgement of their detection by the vehicle being the most important message. There were no clear patterns across the respondents, regarding preference of modality for these external messages, with cultural and infrastructural differences thought to govern responses. Generally, however, conventional signals (lights and beeps) were preferred to text-based messages and spoken words. The results suggest that until these driverless vehicles are able to provide universally comprehensible externally presented information or messages during interaction with other road users, they are likely to contribute to confusing and conflicting interactions between these actors, especially in a shared space setting, which may, therefore, reduce efficient traffic flow.
29

VAM Cluster Optimization

Sjöström, Eric January 2023 (has links)
This thesis will research and evaluate the state of the current ETSI VAM standard. The thesis evaluates and discusses the means of improving the speed and response of ETSI VAM by reducing the load on the radio medium. The research looks to prove that fewer messages broadcasted improve VRU awareness. The thesis focuses mainly on the benefits of VRU clustering as a means of reducing radio medium load through numerical evaluation and physical implementation testing. Evaluation of basic and alternate cluster parameters is performed to find the most optimal ones; alternate clustering strategies are also discussed and proposed. The thesis aims to improve the standard by finding and evaluating alternate methods and parameters in order to propose improved options. / Projektet utvärderar och diskuterar sätten att förbättra hastigheten och responsen hos ETSI VAM genom att minska belastningen på radiomediet. Forskningen syftar till att bevisa att färre meddelanden som sänds förbättrar systemets VRU-medvetenhet. Fokuset ligger huvudsakligen på att utvärdera fördelarna med "VRU-klustring" som ett sätt att minska radiomediebelastningen genom numerisk utvärdering och fysisk testning. Utvärdering av grundläggande och alternativa klusterparametrar utförs för att hitta de mest optimala; alternativa klustringsstrategier diskuteras och föreslås också. Projektet syftar till att förbättra standarden genom att hitta och utvärdera alternativa metoder och parametrar för att föreslå förbättrade alternativ.
30

Effectiveness of Vehicle External Communication Toward Improving Vulnerable Road User Safe Behaviors: Considerations for Legacy Vehicles to Automated Vehicles of the Future

Rossi-Alvarez, Alexandria Ida 25 January 2023 (has links)
Automated vehicles (AVs) will be integrated into our society at some point in the future, but when is still up for debate. An extensive amount of research is being completed to understand the communication methods between AVs and other road users sharing the environment to prepare for this future. Currently, researchers are working to understand how different forms of external communication on the AVs will impact vulnerable road user (VRU) interaction. However, within the last 10 years, VRU casualty rates have continued to rise for all classifications of VRUs. Unfortunately, there is no suggestion that pedestrian fatality rates will ever decrease without some intervention. This dissertation aims at understanding the impacts of eHMI across real-world, complex scenarios with AVs and how researchers can apply those future findings to improve VRUs' judgments to today. A series of studies evaluated the necessity and impact of eHMI on AV–VRU interaction, assessed how the visual components of eHMI influenced VRU crossing decisions, and how variations in a real-world environment (multiple vehicles and scenario complexity) impact crossing decision behavior. Two studies examined how eHMI will impact future interactions between AVs and VRUs. Specifically, to understand how to advance the design of these future devices to avoid unintended consequences that may result. Results from these studies found that the presence and condition of eHMI did not influence participants' willingness to cross. Participants primarily relied on the speed and distance of the vehicle to make their crossing decision. It was difficult for participants to focus on the eHMI when multiple vehicles competed for their attention. Participants typically prioritized their focus on the vehicle that was nearest and most detrimental to their crossing path. Additionally, the type of scenario caused participants to make more cautious crossing decisions. However, it did not influence their willingness to cross. The last study applied the learnings from the first two studies to a foundational perception study for current legacy vehicles. These results showed a significant increase in judgment accuracies with a display. Through analysis across overall conclusions from the 3 studies, five critical findings were identified when addressing eHMI and 3 design recommendations, which are discussed in the penultimate section of this work. The results of this dissertation indicate that eHMI improved VRUs' accuracy of perception of change in vehicle speed. eHMI did not significantly impact VRUs crossing decisions. However, the complexity of the traffic scenarios affected the level of caution participants exhibited in their crossing behavior. / Doctor of Philosophy / An extensive amount of research is being completed to understand the communication methods between AVs and other road users sharing the environment to prepare for this future. Currently, researchers are working to understand how different forms of external communication on the AVs will impact vulnerable road user (VRU) interaction. However, within the last 10 years, VRU casualty rates have continued to rise for all classifications of VRUs. Unfortunately, there is no suggestion that pedestrian fatality rates will ever decrease without some intervention. This dissertation aims at understanding the impacts of eHMI across real-world, complex scenarios with AVs and how researchers can apply those future findings to improve VRUs' judgments to today. A series of studies evaluated the necessity and impact of eHMI on AV–VRU interaction, assessed how the visual components of eHMI influenced VRU crossing decisions, and how variations in a real-world environment (multiple vehicles and scenario complexity) impact crossing decision behavior.

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