Dissertations / Theses on the topic 'Road users'

Pedestrians and bicyclists are the most vulnerable road users and suffer the most severe consequences when crashes take place. An extensive literature is available for crash severity in terms of driver safety, but fewer studies have explored non-motorized users' crash severity. Furthermore, most research efforts have examined pedestrian and bicyclist crash severity in urban areas. This study focuses on state roads (mostly outside major urban areas) and aims to identify contributing risk factors of fatal and severe crashes involving pedestrians and bicyclists in state roads. Two ordinal regression models were developed (one for pedestrian and the other for bicyclist crashes) to examine crash severity risk factors. Additional models were developed to investigate road and traffic characteristics that could increase the likelihood of fatal crashes. In the model for pedestrian crash severity risk factors such as age, vehicle type and movement, light conditions, road classification, traffic control device, posted speed limit, location of the pedestrian and wet road surface during clear weather conditions are statistically significant. The bicyclist crash severity model indicates that age, crash location, vehicle movement and alcohol intoxication during dark conditions are statistically significant. In terms of road characteristics and traffic conditions, the models suggested risk factors such as arterials, light conditions, posted speed limit, roadways, and high heavy vehicle volume, increased the odds of a crash being fatal. The results seem to suggest that besides improvements in roadway characteristics, additional countermeasures to reduce crash severity for vulnerable users should include separation of vulnerable users from traffic, educational campaigns, more strict control of alcohol intoxicated drivers, and protection strategies of senior pedestrians.

Traffic safety has traditionally been measured by analyzing historical accident data, which is a reactive method where a certain number of accidents must occur in order to identify the safety problem. An alternative safety assessment method is to use proximal safety indicators that are defined as measures of accident proximity, which is considered a proactive method. With this method it is possible to detect the safety problem before the accidents have happened. To be able to detect problems in traffic situations in general, microscopic simulation is commonly used. In these models it may be possible to generate representative near-accidents, measured by proximal safety indicator techniques. A benefit of this would be the possibility to experiment with different road designs and evaluate the traffic safety level before reconstructions of the road infrastructure. Therefore has an investigation been performed to test the possibility to identify near-accidents (conflicts) in a microscopic simulation model mimicking the Traffic Conflict Technique developed by Hydén (1987). In order to perform the investigation a case study has been used where an intersection in the city center of Stockholm was studied. The intersection has been rebuilt, which made it possible to perform a before and after study. For the previous design there was a traffic safety assessment available which was carried out using the Traffic Conflict Technique. Microscopic simulation models representing the different designs of the intersection were built in PTV Vissim. In order to evaluate and measure the traffic safety in reality as well as in the microscopic simulation models, a traffic safety assessment was performed in each case. The traffic safety assessment in field for the present design was carried out as a part of this thesis. The main focus of this thesis was the road safety for vulnerable road users. The method to identify conflicts in the simulation model has been to extract raw data output from the simulation model and thereafter process this data in a Matlab program, aiming to mimic the Traffic Conflict Technique. The same program and procedure was used for both the previous and the present design of the intersection. The results from the traffic safety assessment in the simulation model have been compared to the results from the field study in order to evaluate how well microscopic simulation works as an evaluation tool for traffic safety in new designs. The comparison shows that the two methods of conflict identification cannot replace each other straight off. But with awareness of the differences between the methods, the simulation model could be used as an indication when evaluating the level of traffic safety in a road design.

A new convolutional deep feedforward network (C-DFN) is proposed to detect vulnerable road users at 57.9% misclassification rate using Caltech Dataset. Instead of going deeper, three C-DFN is stacked to achieve 43.4% misclassification rate. Part-based C-DFN further reduces the rate of 42.5% to tackle occlusion problem. In addition, investigation of adaptive activation functions are performed to understand the effect of saturated and non-saturated functions in mitigating the vanishing and exploding gradient issues of neural networks.

This dissertation argues that the period 1900-1963 may be seen as one in which various models for the governance of roads and their users were developed. Demands for governance came from road campaigners and governmental bodies; these various groups called for, and attempted to implement, such governance in various ways. Of all these methods, scientific governance, via experiment and road network architecture, came decisively to supervene. The development of centralised and localised forms of governance, channelled through the civil and traffic engineering implemented by its County Surveyors, facilitated the state governance of Britain's road network and its users. The co-operation of road users was vital to the success of this state governance. Previously a law unto themselves, road users (most especially motorists) were self-governed by a gentlemanly code of tacit rules of the road. Overhauling the mindset and behaviour of road users first required the reform of the systematic structures of highway administration, along with legislative enforcement. This, however, was dependent upon the premise of central governance and thus government acceptance of roads as a national responsibility. This state of affairs brought with it two important factors. First, the financial means to fund road improvement measures was provided. Second, centres of scientific investigations were established, and credible methods developed, to explore advanced methods of construction and systems of traffic control. Understanding the interaction of roads, vehicles, and users was fundamental to the successful implementation of scientific governance. Roads were a socio-technical problem that required a scientific solution, both in terms of their physical construction and in terms of the ways in which they were used, and used safely. Science was in-built into in the driving experience through such innovations as the use of white lines, the implementation of speed limits, road layouts and road signs. Together, these and other developments constructed the British road network, and worked as means of governing user behaviour. The result of all these factors and developments was the State-based, scientific governance of British roads and their users.

Motorised countries have more fatal road crashes in rural areas than in urban areas. In Australia, over two thirds of the population live in urban areas, yet approximately 55 percent of the road fatalities occur in rural areas (ABS, 2006; Tziotis, Mabbot, Edmonston, Sheehan & Dwyer, 2005). Road and environmental factors increase the challenges of rural driving, but do not fully account for the disparity. Rural drivers are less compliant with recommendations regarding the “fatal four” behaviours of speeding, drink driving, seatbelt non-use and fatigue, and the reasons for their lower apparent receptivity for road safety messages are not well understood. Countermeasures targeting driver behaviour that have been effective in reducing road crashes in urban areas have been less successful in rural areas (FORS, 1995). However, potential barriers to receptivity for road safety information among rural road users have not been systematically investigated. This thesis aims to develop a road safety countermeasure that addresses three areas that potentially affect receptivity to rural road safety information. The first is psychological barriers of road users’ attitudes, including risk evaluation, optimism bias, locus of control and readiness to change. A second area is the timing and method of intervention delivery, which includes the production of a brief intervention and the feasibility of delivering it at a “teachable moment”. The third area under investigation is the content of the brief intervention. This study describes the process of developing an intervention that includes content to address road safety attitudes and improve safety behaviours of rural road users regarding the “fatal four”. The research commences with a review of the literature on rural road crashes, brief interventions, intervention design and implementation, and potential psychological barriers to receptivity. This literature provides a rationale for the development of a brief intervention for rural road safety with a focus on driver attitudes and behaviour. The research is then divided into four studies. The primary aim of Study One and Study Two is to investigate the receptivity of rural drivers to road safety interventions, with a view to identifying barriers to the efficacy of these strategies.

Motorised countries have more fatal road crashes in rural areas than in urban areas. In Australia, over two thirds of the population live in urban areas, yet approximately 55 percent of the road fatalities occur in rural areas (ABS, 2006; Tziotis, Mabbot, Edmonston, Sheehan & Dwyer, 2005). Road and environmental factors increase the challenges of rural driving, but do not fully account for the disparity. Rural drivers are less compliant with recommendations regarding the “fatal four” behaviours of speeding, drink driving, seatbelt non-use and fatigue, and the reasons for their lower apparent receptivity for road safety messages are not well understood. Countermeasures targeting driver behaviour that have been effective in reducing road crashes in urban areas have been less successful in rural areas (FORS, 1995). However, potential barriers to receptivity for road safety information among rural road users have not been systematically investigated. This thesis aims to develop a road safety countermeasure that addresses three areas that potentially affect receptivity to rural road safety information. The first is psychological barriers of road users’ attitudes, including risk evaluation, optimism bias, locus of control and readiness to change. A second area is the timing and method of intervention delivery, which includes the production of a brief intervention and the feasibility of delivering it at a “teachable moment”. The third area under investigation is the content of the brief intervention. This study describes the process of developing an intervention that includes content to address road safety attitudes and improve safety behaviours of rural road users regarding the “fatal four”. The research commences with a review of the literature on rural road crashes, brief interventions, intervention design and implementation, and potential psychological barriers to receptivity. This literature provides a rationale for the development of a brief intervention for rural road safety with a focus on driver attitudes and behaviour. The research is then divided into four studies. The primary aim of Study One and Study Two is to investigate the receptivity of rural drivers to road safety interventions, with a view to identifying barriers to the efficacy of these strategies.

Anticipar les intencions dels usuaris vulnerables (VRU, per les sigles en anglès), com a vianants i ciclistes, pot ser crític per a una conducció segura i confortable. Aquest és el cas quan condueix una persona i, per tant, aquestes intencions també s’han de tenir en compte pels sistemes que brinden qualsevol nivell d’assistència a la conducció, és a dir, des dels sistemes avançats d’assistència al conductor (ADAS, en anglès) fins als vehicles totalment autònoms (AVs, en anglès). En aquesta tesi doctoral, mostrem com els últims avenços en l’estimació de la postura humana mitjançant visió monocular, és a dir, aquells que depenen de xarxes neuronals convolucionals (CNN, en anglès) profundes, permeten reconèixer les intencions de tals VRU. En el cas dels ciclistes, assumim que segueixen els codis de trànsit establerts per indicar, mitjançant senyals amb el braç, futurs girs a l’esquerra o la dreta, així com la intenció de parar-se. En el cas dels vianants, no es pot suposar a priori cap indicació. En canvi, suposem que el patró de caminar d’un vianant pot permetre determinar si ell / ella té la intenció de creuar la carretera al camí del vehicle (parcialment) automatitzat, de manera que aquest vehicle hagi de maniobrar en conseqüència (per exemple, reduir la velocitat o aturar-se). En aquesta tesi doctoral, mostrem com es pot fer servir la mateixa metodologia per reconèixer les intencions dels vianants i ciclistes. Per als vianants, vam realitzar experiments amb dades de Daimler i JAAD, disponibles públicament. Per als ciclistes, no hem trobat dades anàlogues, per tant, hem creat les nostres pròpies dades mitjançant l’adquisició i anotació de seqüències de vídeo de ciclistes que pretenem compartir amb la comunitat científica. En conclusió, el mètode proposat en aquesta tesi proporciona nous resultats d’avantguarda en el reconeixement de la intenció dels VRU.
Anticipating the intentions of vulnerable road users (VRUs) such as pedestrians and cyclists can be critical for performing safe and comfortable driving maneuvers. This is the case for human driving and, therefore, should be taken into account by systems providing any level of driving assistance, i.e. from advanced driver assistant systems (ADAS) to fully autonomous vehicles (AVs). In this PhD work, we show how the latest advances on monocular vision-based human pose estimation, i.e. those relying on deep Convolutional Neural Networks (CNNs), enable to recognize the intentions of such VRUs. In the case of cyclists, we assume that they follow the established traffic codes to indicate future left/right turns and stop maneuvers with arm signals. In the case of pedestrians, no indications can be assumed a priori. Instead, we hypothesize that the walking pattern of a pedestrian can allow us to determine if he/she has the intention of crossing the road in the path of the egovehicle, so that the ego-vehicle must maneuver accordingly (e.g. slowing down or stopping). In this PhD work, we show how the same methodology can be used for recognizing pedestrians and cyclists’ intentions. For pedestrians, we perform experiments on the publicly available Daimler and JAAD datasets. For cyclists, we did not found an analogous dataset, therefore, we created our own one by acquiring and annotating corresponding video-sequences which we aim to share with the research community. Overall, the proposed pipeline provides new state-of-the-art results on the intention recognition of VRUs.

Chaque année, des millions de personnes meurent et beaucoup d'autres subissent des séquelles graves à la suite d'accidents de la route. Malgré une multitude d’initiatives, le nombre de cas mortels et d'accidents graves augmente chaque année en engendrant des problèmes préoccupants à la fois sociaux, économiques et sanitaires. En raison de leur nombre élevé et de l'absence de protection personnelle, plus de la moitié de ces décès concerne les usagers vulnérables (en anglais, vulnerable road users - VRU) regroupant les piétons, cyclistes et motocyclistes. Les appareils mobiles, combinés à la technologie de Fog Computing (ou informatique géodistribuée, ou même informatique en brouillard), représentent une solution réaliste à court terme pour les protéger en les avertissant de l’imminence d'un accident de circulation. L’omniprésence des appareils mobiles et leurs capacités de calcul élevées font de ces appareils un élément important à considérer dans les solutions de sécurité routière. Le Fog Computing offre des fonctionnalités adaptées aux applications de sécurité routière, puisqu’il s’agit d’une extension du Cloud Computing permettant de rapprocher les services informatiques, le stockage et le réseau au plus près des utilisateurs finaux. Par conséquent, dans cette thèse, nous proposons une architecture réseau sans infrastructure supplémentaire (PV-Alert) pour des fins de sécurité routière et reposant uniquement sur les appareils mobiles des VRU et des conducteurs sur la route avec l’aide du concept de Fog Computing. Les données géographiques et cinématiques de ces appareils sont collectées et envoyées périodiquement au serveur fog situé à proximité. Le serveur fog traite ces données en exécutant un algorithme de calcul de risque d’accident de circulation et renvoie des notifications en cas d'accident imminent. L’évaluation de cette architecture montre qu’elle est capable de générer des alertes en temps réel et qu’elle est plus performante que d’autres architectures en termes de fiabilité, d’évolutivité et de latence
Annually, millions of people die and many more sustain non-fatal injuries because of road traffic crashes. Despite multitude of countermeasures, the number of causalities and disabilities owing to traffic accidents are increasing each year causing grinding social, economic, and health problems. Due to their high volume and lack of protective-shells, more than half of road traffic deaths are imputed to vulnerable road users (VRUs): pedestrians, cyclists and motorcyclists. Mobile devices combined with fog computing can provide feasible solutions to protect VRUs by predicting collusions and warning users of an imminent traffic accident. Mobile devices’ ubiquity and high computational capabilities make the devices an important components of traffic safety solutions. Fog computing has features that suits to traffic safety applications as it is an extension of cloud computing that brings down computing, storage, and network services to the proximity of end user. Therefore, in this thesis, we have proposed an infrastructure-less traffic safety architecture that depends on fog computing and mobile devices possessed by VRUs and drivers. The main duties of mobile devices are extracting their positions and other related data and sending cooperative awareness message to a nearby fog server using wireless connection. The fog server estimates collision using a collision prediction algorithm and sends an alert message, if an about-to-occur collision is predicted. Evaluation results shows that the proposed architecture is able to render alerts in real time. Moreover, analytical and performance evaluations depict that the architecture outperforms other related road safety architectures in terms of reliability, scalability and latency. However, before deploying the architecture, challenges pertaining to weaknesses of important ingredients of the architecture should be treated prudently. Position read by mobile devices are not accurate and do not meet maximum position sampling rates traffic safety applications demand. Moreover, continuous and high rate position sampling drains mobile devices battery quickly. From fog computing’s point of view, it confronts new privacy and security challenges in addition to those assumed from cloud computing. For aforementioned challenges, we have proposed new solutions: (i) In order to improve GPS accuracy, we have proposed an efficient and effective two-stage map matching algorithm. In the first stage, GPS readings obtained from smartphones are passed through Kalman filter to smooth outlier readings. In the second stage, the smoothed positions are mapped to road segments using online time warping algorithm. (ii) position sampling frequency requirement is fulfilled by an energy efficient location prediction system that fuses GPS and inertial sensors’ data. (iii) For energy efficiency, we proposed an energy efficient fuzzy logic-based adaptive beaconing rate management that ensures safety of VRUs. (iv) finally, privacy and security issues are addressed indirectly using trust management system. The two-way subjective logic-based trust management system enables fog clients to evaluate the trust level of fog servers before awarding the service and allows the servers to check out the trustworthiness of the service demanders. Engaging omnipresent mobile device and QoS-aware fog computing paradigm in active traffic safety applications has the potential to reduce overwhelming number of traffic accidents on VRUs

The study aims to improve the safety and stability of bicycles, in particular, in adverse weather conditions. One of the main tasks of the project is to compare the results of the bicycle simulator test conducted at the PICS-L laboratory, at the Gustave Eiffel University in Paris, and the results of a real-life experiment conducted in Stockholm using an instrumented bicycle. As a first step, the importance of simulators and the state of art of bicycle simulators are presented. Next, the first two tests conducted in the PICS-L laboratory are shown, as a brief introduction to the third one, which is the focus of this research. The third test is divided into experiment and simulation. The experiment, conducted between the end of 2020 and the beginning of 2021, was carried out by 22 participants. After a description of the instrumented bicycle, the analysis of the participants and the main sensor outputs, speed, power, and cadence, were explained. After that, the mathematical model used for the realization of the PICS-L laboratory bicycle simulator and its various components are described. The results of the analysis of the simulation and the main outputs are then presented. Finally, the comparison between the two analyses is reported, with particular attention to the criticalities of the bicycle simulator. It will be possible therefore to estimate the behavioral validity of the simulator. The criticalities of the urban street of Stockholm where the experiment has been carried out are then described.

Over the past twenty years bicycle use as a mode of transportation has grown considerably in the United States. Other studies have examined the individual bicyclist’s risk in proportion to the growth in cycling across cities, a phenomenon referred to as ‘safety in numbers.’ This study expands from that research and examines the effect of cyclists on road safety for all road users. The study examines the roles of bicycle modal split, a city wide analysis, and bicycle infrastructure, a site based analysis, in road safety outcomes. For the city based analysis, twenty years of crash data in 12 California cities were analyzed over a 20 year period. This study primarily used census data and State wide Integrated Traffic Records System (SWITRS) data. This study concludes that as bicycle modal split increases in a city, the traffic fatalities tend to decrease and the relationship is an exponential function. The site based analysis focuses on the effects of installing a bicycle lane on a street and examined its effect on injury crashes. 20 sites in San Francisco, CA that had bike lanes installed on them were compared to 25 control group sites, also in San Francisco, that did not have any bike lanes or other significant changes. An Empirical Bayes method of analysis was done to test its effects and determined that the effects were statistically significant.

In recent years, accidents between trucks and other vehicles have decreased while accidents be-tween trucks and vulnerable road-users have increased. The reason for this is unknown, which is why this Master’s Thesis project was initiated. The project is a co-operation between two students from two different universities, LTU and KTH, done for Volvo GTT in Gothenburg. A user study containing interviews and co-rides has been executed with truck drivers in the Gothenburg area during the autumn of 2017. A survey was also sent to different organizations for cyclists, motorcyclists, car drivers and to Facebook groups for the two universities. Critical situations mentioned by the truck drivers were chosen with the help of the survey answers from other road-users. Right hand turns with a truck that crosses a bike lane and intersections with a zebra crossing were the situations the project focused on, based on the Volvo Trucks Safety Report 2017 which stated those situations as the most dangerous. Serious accidents occurring when a truck turns right is when vulnerable road-users end up under the truck’s back wheels, which cuts corners. This made the project focus on trying to find a solution that could reduce this type of accident. The project also concentrated on increasing the commu-nication at intersections, based on the survey comments where it became clear that eye contact is insufficient, which led to focus on communication between trucks and fellow road-user instead. Through benchmarking, literature reviews and idea generation the final concept solution was cre-ated and developed after a workshop. The final concept solution is a turning projection that visualizes the dangerous area when a truck is turning and a light matrix in the front grille for increasing the understanding, visually, of the truck driver’s intentions of slowing down or speeding up. The final concept solution contains a zebra crossing projection in the front of the truck to facilitate the communication today, and in the future to even replace eye contact and gestures done between truck driver and fellow road-users at crossings. Further development of the concept solution includes choices and adaption of available technology and research concerning legislation for color usage on lights and projections to the front and sides of the trucks.

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.

QC 20171013

Background. Over the years, between 2013 and 2017, accidents between HeavyGoods Vehicles and Pedestrians have come to increase. Leading causes stem frominattentiveness and lack of communication between driver and pedestrians. Withthe advent of Autonomous vehicles, set to be able to reduce accidents, uncertainties in how communication and trust between humans and machines will be formed re-mains. Objectives. The research aim has been to understand the difficulties and problemssurrounding heavy vehicles, and the problems that today’s heavy vehicle operators faces, from which a technical solution that addressees the uncovered needs, is devel-oped. Methods. Design Research Methodology and MSPI Innovation Process has beenused in combination for acquiring and validating information around the problem.Shadowing sessions, unstructured interviews has been used for acquiring information.Literature reviews have been done to find academic validation in hypotheses statedthroughout the research. From the information gathered, iterative prototypes havebeen built. Results. From the needfinding that was conducted, safety around trucks was thefield on which the scope of the research was focused around. Due the larger size oftruck, decision-making through eye contact and intention determining is set to beharder when dealing with heavy vehicles, leading to an uncertainty around heavyvehicles residing with pedestrians in how to act around these. With the operatorsof these vehicles finding the unpredictable nature of pedestrians and cyclist in trafficto be troublesome and safety imposing, the research aim was set around addressing these needs. A communication console was developed, that is able to communi-cate safety-critical information between heavy vehicle operators and vulnerable road users, as means of reducing front collisions between said parts. Conclusions. The console has been developed through iterative prototyping andtesting, with design requirements being acquired through learnings and feedbackgathered from each iteration. The resulting communication console being presentedis able to share critical information being sought by pedestrians for decision-making,primarily that of eye contact and intentions of oncoming vehicles. The system servesas a proof of concept, that could through extensive traffic safety testing, help reducefront collisions between Heavy Goods Vehicles and Vulnerable Road Users, as well as, through further development, become the central communication console for au-tonomous vehicles to ensure partnership and intuitive communication between these and the surroundings.

The positive contributions of the electronic signs around school and non-school zones are real and need to be expanded. The shift of this vital contribution is coming from minimising harm with lesser fatalities. This is what 'Towards Zero Strategy' of Perth is pursuing. To continue this real achievement, speed enforcement will remain a crucial element, particularly when it is on the spot. Young drivers may start to response. If they don't, the speed awareness courses should influence them along with other speeders in a new sustainable jurisdiction.

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

This thesis is a compendium of research from roadside, drinking bars, hospitals and police accident records in Ghana. The thesis investigated the natural prevalence of alcohol use among road users at these settings and the potential crash risk associated with this behavior. The research established that the prevalence of driving or operating a vehicle with elevated BAC above the legal limit was high. This was however underreported by the police. This research underscores the need for enhanced enforcement of the drink-driving law, and education of road users on responsible alcohol consumption among road users to improve upon road safety in Ghana.

Road with transit traffic in urban areas entails meeting between relatively high-speed vehicle traffic and unprotected road users in a residential environment. In Sweden there are many, small and large urban areas that are crossed by roads in their central parts. These roads can cause traffic at relatively high speed to affect and create problems for the residential environment in the urban area. Roads in urban areas become problematic in relation to safety because traffic is to interact with unprotected road users. With the citizens' movement pattern as a starting point, this study illustrates how the design of the road can be adapted to the citizens to reduce the risk of accidents. The aim of this study was to investigate the unprotected road users' experience and movement patterns in the road environment at Storgatan in the urban area Robertsfors. The focus is on safety for the unprotected road users and to provide suggestions to improve safety. This study had a qualitative design and based on observation of movement's patterns among people using Storgatan as well as eight semi-structured interviews. The result showed that unprotected road users, expressed the need to reduce the speed of vehicles early in the urban area, to clearly visualize and protect unprotected road users and the importance of the road being part of the urban area and not a transit road. It also emerged that vehicle traffic has a prominent role in urban environment and should be questioned, as the urban area should be perceived as a safe and attractive environment for the residents. The interaction between vehicle traffic and unprotected road users is clearly unequal based on the results of this study.

Thesis (Ph. D.) -- University of Maryland, College Park, 2007.
Thesis research directed by: Civil Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Within any ecosystem, information needs are shared to be fulfilled and to support the ecosystem in a way or another. They are vital for designing appropriate information systems that will provide those needs. In this thesis, the gravel road ecosystem is studied, where efficient information sharing is not enabled due to the lack of appropriate information systems. Thus,when focusing on the gravel roads ecosystem, information plays a crucial role regarding the maintenance acts upon these roads. Moreover, not enough literature investigates theinformation needs of gravel roads stakeholders with the aim to improve the maintenance ofthese roads. Therefore, this thesis intends to elicit information needs of gravel road stakeholders by performing an exploratory case study. The case study forms a part of an ongoing project with the goal to build a cloud-based information system for a sustainable gravel road maintenance. Data were collected through telephone- and online-based interviews with several key stakeholders in Sweden and were thereafter structured through template analysis. The major findings were a set of information needs and several needed sensors within the pre-mentioned information system. This thesis concluded that the future cloud-based information system in the ongoing project is a useful system for sharing vital information among future gravel roads stakeholders, considering the variety of needed information that affects the maintenance of the gravel roads.
Sustainable maintenance of gravel roads

Nell’elaborato viene studiato il fenomeno dell’incidentalità singola delle utenze deboli sulla strada (perdita di controllo, scivolamento ecc..ecc..), con particolare enfasi nell’analizzare le conseguenze traumatiche dovute all’impatto con la superficie stradale. Una nuova tecnologia viene sviluppata per rendere le pavimentazioni di piste ciclabili, marciapiedi e zone pedonali con capacità di assorbimento degli impatti, prevenendo, o riducendo drasticamente, la probabilità e entità di eventi traumatici a seguito di una caduta. Attraverso una stesa di prova avvenuta ad Imola (BO), si sono analizzate e risolte le problematiche dovute alle discrepanze riscontrate fra “costruzione” in laboratorio e costruzione nella realtà urbana. La nuova tecnologia, infatti, è stata studiata come “construction-friendly”, permettendo alle società di costruzione e pavimentazione di stendere il nuovo manto protettivo con strumenti e macchinari tradizionali. Infine l’asfalto modificato è stato testato nei laboratori svedesi del KTH – Royal Institute of Technology per provarne l’efficacia in termini di assorbimento degli impatti. Nel “Drop Impact Test”, test specifico per l’approvazione dei caschi protettivi da bicicletta, l’asfalto modificato ha performato ben al di sotto della soglia di approvazione dei caschi da ciclista, e si colloca in un range di valore di accelerazione lineare perfino al di sotto della soglia di “Low Risk of Injuries”. La nuova tecnologia, inoltre, fa utilizzo di gomma granulata riciclata da pneumatici fuori uso. Tale dettaglio conferisce maggiore sostenibilità al progetto: oltre all’utilizzo di legante a freddo, che diminuisce le emissioni di CO2, e di incentivare l’utilizzo della mobilità dolce attraverso una più sicura rete infrastrutturale, l’utilizzo di gomma riciclata dà nuova vita al materiale che altrimenti andrebbe in discarica e prolunga, così, la vita utile del materiale.

Le domaine du calcul haute performance (i.e. la science des super-calculateurs)est caractérisé par l’évolution continuelle des architectures de calcul, la proliférationdes ressources de calcul et la complexité croissante des problèmes que les utilisateursveulent résoudre. Un des logiciels les plus importants de la pile logicielle dessupercalculateurs est le Système de Gestion des Ressources et des Tâches. Il est lelien entre la charge de travail donnée par les utilisateurs et la plateforme de calcul. Cetype de logiciels spécialisés fournit des fonctions pour construire, soumettre, planifieret surveiller les tâches dans un environnent de calcul complexe et dynamique.Pour pouvoir atteindre des supercalculateurs exaflopiques, de nouvelles con-traintes et objectifs ont été inventés. Cette thèse développe et teste l’idée que lesutilisateurs de ces systèmes peuvent aider à atteindre l’échelle exaflopique. Spé-cifiquement, nous montrons des techniques qui utilisent les comportements desutilisateurs pour améliorer la consommation énergétique et les performances glob-ales des supercalculateurs.Pour tester ces nouvelles techniques, nous avons besoin de nouveaux outils etméthodes qui sont capables d’aller jusqu’à l’échelle exaflopique. Nous proposonsdonc des outils qui permettent de tester de nouveaux algorithmes capables des’exécuter sur ces systèmes. Ces outils sont capables de fonctionner sur de petitssupercalculateurs en émulant ou simulant des systèmes plus puissants. Après avoirévalué différentes techniques pour mesurer l’énergie dans les supercalculateurs, nousproposons une nouvelle heuristique, basée sur un algorithme répandu (Easy Backfill-ing), pour pouvoir contrôler la puissance électrique de ces énormes systèmes. Nousmontrons aussi comment, en utilisant la même méthode, contrôler la consommationénergétique pendant une période de temps. Le mécanisme proposé peut limiterla consommation énergétique tout en gardant des performances satisfaisantes. Sil’énergie est une ressource limitée, il faut la partager équitablement. Nous présen-tons de plus un mécanisme permettant de partager la consommation énergétiqueentre les utilisateurs. Nous soutenons que cette méthode va motiver les utilisateursà réduire la consommation énergétique de leurs calculs. Finalement, nous analysonsle comportement actuel et passé des utilisateurs pour améliorer les performancesdes supercalculateurs. Cette approche non seulement surpasse les performances destravaux existants, mais aussi ouvre la voie à l’utilisation de méthodes semblablesdans d’autres aspects des Systèmes de Gestion des Ressources et des Tâches
The field of High Performance Computing (HPC) is characterized by the contin-uous evolution of computing architectures, the proliferation of computing resourcesand the increasing complexity of applications users wish to solve. One of the mostimportant software of the HPC stack is the Resource and Job Management System(RJMS) which stands between the user workloads and the platform, the applica-tions and the resources. This specialized software provides functions for building,submitting, scheduling and monitoring jobs in a dynamic and complex computingenvironment.In order to reach exaflops HPC systems, new constraints and objectives havebeen introduced. This thesis develops and tests the idea that the users of suchsystems can help reaching the exaflopic scale. Specifically, we show and introducenew techniques that employ users behaviors to improve energy consumption andoverall cluster performances.To test the proposed techniques, we need to develop new tools and method-ologies that scale up to large HPC clusters. Thus, we designed adequate tools thatassess new RJMS scheduling algorithms of such large systems. These tools areable to run on small clusters by emulating or simulating bigger platforms. Afterevaluating different techniques to measure the energy consumption of HPC clusters,we propose a new heuristic, based on the popular Easy Backfilling algorithm, inorder to control the power consumption of such huge systems. We also demonstrate,using the same idea, how to control the energy consumption during a time period.The proposed mechanism is able to limit the energy consumption while keepingsatisfying performances. If energy is a limited resource, it has to be shared fairly.We also present a mechanism which shares energy consumption among users. Weargue that sharing fairly the energy among users should motivate them to reducethe energy consumption of their applications. Finally, we analyze past and presentbehaviors of users using learning algorithms in order to improve the performancesof the parallel platforms. This approach does not only outperform state of the artmethods, it also shows promising insight on how such method can improve otheraspects of RJMS

Flooding can severely disrupt transportation systems. When safety measures are limited to road closures, vehicles affected by the flooding have an origin, destination, or path segment that is closed or soon-to-be flooded during the trip's duration. This thesis introduces a framework to provide routing assistance and trip cancellation recommendations to affected vehicles. The framework relies on the connected vehicle environment for real-time link performance measures and flood data and evaluates the trip of the vehicle to determine whether it is affected by the flood or not. If the vehicle is affected and can still leave its origin, the framework generates the corresponding routing assistance in the form of hyperpath(s) or set of alternative paths. On the other hand, a vehicle with a closed origin receives a warning to wait at origin, while a vehicle with an affected destination is assigned to a new safe one. This framework is tested on two transportation networks. The evaluation of the framework's scalability to different network sizes and the sensitivity of the results to various flood characteristics, policy-related variables and other dependencies are performed using simulated vehicle data and hypothetical flood scenarios. The computation times depends on the network size and flood depth but have generally an average of 1.47 seconds for the largest tested network and deepest tested flood. The framework has the potential to alleviate the impacts and inconveniences associated with flooding.
Master of Science

This PhD work investigates the communication and positioning technologies for realizing vehicle to Vulnerable Road User (V2VRU) safety interactions. The thesis presents a design of a software-defined VRU safety solution based on smartphone hardware, allowing for the incorporation of emerging technologies such as Internet-of-Things (IoT) protocols, real-time kinematic (RTK) positioning techniques, and 4G/5G mobile broadband (MBB) services. Experimental results also demonstrate the feasibility and performance of 4G internet connection and RTK positioning to meet the key technical requirements for V2VRU safety applications.

The thesis aims to explore attitudes and the perceived image of cycling in Mexico City and the extent to which this may be a deterrent for engaging in cycle commuting. It also explores the existence of attitudinal transport segments. Transport segments were investigated using a questionnaire developed by the Segment Project EU. Data about attitudes were collected in the same survey from a theory-based questionnaire developed from the Theory of Planned Behaviour (TPB), extended with constructs from the Social Comparison Theory (SCT) and the Material Possessions Model (MPM). The survey was distributed on-street and online, with a simple random sample of 401 road users. The sample characteristics were: no cyclists or infrequent cyclists, living and working in Mexico City, and aged 18-60. The results indicate that the same attitudinal transport segments identified in Europe also exist in Mexico City. They also show that cycling attributes, attitudes to cycling, social comparison, and social image and prestige were the most important factors influencing intention to cycle, explaining 42% of the variance in intention to cycle. Notably, when the evaluation of cycling was negative, the intention to commute by cycling was weaker; when the attributes of cycling and the social image linked to cycling were positive, the intention to cycle commute was strengthened. The effect of social comparison is not clearly established. Although the results from this study are specific to Mexico City, they indicate areas of interest to transportation planners in other regions, especially in those cities where intention to cycle is linked to its perceived image and there is political ambition to promote a positive image of cycling and stimulate modal shift. Moreover, this study contributes to the current literature developing applications of the TPB. Future research may include further investigating social comparison as a latent construct underlying intention to cycle.

Traffic accidents is one of the major causes of fatalities and economic loss around the world. Thus, there is an urgent need for a better understanding about the factors that contribute to accidents so that the accidents can be prevented in the future. The research objective of this thesis is to analyze the traffic accidents between vehicles and unprotected road users (pedestrians and bicycles) in Stockholm, finding spatial distribution patterns, related attributes and examining relationships between accidents and a number of vehicle flows. The data is first analyzed with general statistical analysis to examine the basic characteristics. There is no apparent trend of change among the number of accidents per year, while the numbers of accidents happening from May to October is higher than the rest of the year except for July due to less traffic during holiday period. Most traffic accidents occur in overcast weather, on a dry road surface, or during the day. In the spatial analysis part of the thesis, Global Moran’s I is used to detect whether there is an attribute-related spatial distribution pattern. Hot spot analysis is then applied on the clustered attributes to find significant hot and cold spots over the study area. The conclusions are that road surface conditions and occurrence time during day/night are two related factors that influence traffic accidents while weather is not considered a related attribute since the accidents distribute randomly in terms of weather, of which it is difficult to obtain temporally-aligned, detailed local information for further analysis. Different parameters are selected and discussed during the process. When calculating the distance between two accidents in traffic accident analysis, Manhattan distance is more appropriate than Euclidean distance since traffic accidents are restricted to the road network. The distance band determines scales of analysis tools, with 50 meters on an intersection and 500 meters for a larger region in Stockholm. Most hot spots arise at intersections and roundabouts where different types of traffic flows meet each other. The result of the relationships between traffic accidents and different types of vehicle flows shows that the correlation coefficients between number of traffic accidents and traffic flows are low, meaning that there is no obvious correlation between them, which is also proved by the scatter plots. Poisson regression model is applied on the traffic accident data. As a result, high-risk and low-risk areas in Stockholm are pointed out. Some are consistent with the hot-spot analysis result.

This paper presents the findings regarding speed and behaviour of e-scooter users in the context of Trondheim city (Norway). The study consisted primarily of an observational study, where the speed of e-scooter users was measured, and their behaviour registered. A survey was also carried out to complement the observations and investigate the underlying motivations of both users and non-users of e-scooters. The observations were carried out on 6 different streets in the city centre. Road user, traffic and street characteristics that could influence user behaviour was noted. For each e-scooter user the following variables were registered: speed, other road users present, gender, age (≤ 35 or > 35), distance from pedestrians when passing, speed adaptation, type of facility used and shared or private e-scooter. A total of 204 e-scooters were observed. The speed data was analysed both through basic between group comparisons, as well as through estimation of a generalised linear regression model. The average speed was 15,40 km/h. The most common type of users was a male, younger than 35 years, riding a shared e-scooter without interactions with others. The drivers who ride in the roadway are the fastest, followed by those who ride in the cycle path/lane. The e-scooter users reduce the speed in the presence of other vulnerable users and in crowded conditions. Age and gender had very little effect on the speed. The survey was distributed on the street and posted on the net. There were just 87 respondents and only 30% of them use e-scooters. In general, the survey confirms the results from the observations. The results show that in the studied context the e-scooter users are more like bicyclists than pedestrians, preferring to use bicyclist facilities where possible, and having a speed closer to a bicyclist.

Traffic-related injuries represent a global public health problem, and contribute largely to mortality and years lived with disability worldwide. Over the course of the last decades, improvements to road traffic safety and injury surveillance systems have resulted in a shift in focus from the prevention of motor vehicle accidents to the control of injury events involving vulnerable road users (VRUs), such as cyclists and moped riders. There have been calls for improvements to the evaluation of safety interventions due to methodological problems associated with the most commonly used study designs. The purpose of this licentiate thesis was to assess the strengths and limitations of the interrupted time series (ITS) design, which has gained some attention for its ability to provide valid effect estimates. Two national road safety interventions involving VRUs were selected as cases: the Swedish bicycle helmet law for children under the age 15, and the tightening of licensing rules for Class 1 mopeds. The empirical results suggest that both interventions were effective in improving the safety of VRUs. Unless other concurrent events affect the treatment population at the exact time of intervention, the effect estimates should be internally valid. One of the main limitations of the study design is the inability to identify why the interventions were successful, especially if they are complex and multifaceted. A lack of reliable exposure data can also pose a further threat to studies of interventions involving VRUs if the intervention can affect the exposure itself. It may also be difficult to generalize the exact effect estimates to other regions and populations. Future studies should consider the use of the ITS design to enhance the internal validity of before-after measurements.
Traffic-related injuries represent a global public health problem, and contribute largely to mortality and years lived with disability. Over the course of the last decades, improvements to road traffic safety and injury surveillance systems have resulted in a shift in focus from motor vehicle accidents to injury events involving vulnerable road users (VRUs), such as cyclists and moped riders. There have been calls for improvements to the evaluation of safety interventions due to methodological problems associated with the most commonly used study designs. The purpose of this licentiate thesis was to assess the strengths and limitations of the interrupted time series (ITS) design, which has gained some attention for its ability to provide valid effect estimates while accounting for secular trends. Two national interventions involving VRUs were selected as cases: the Swedish bicycle helmet law for children under the age 15, and the tightening of licensing rules for Class 1 mopeds. The empirical results suggest that both interventions were effective. These results are discussed in the light of some methodological considerations regarding internal and external validity, data quality and the ability to fully understand key causal mechanisms behind complex interventions.

Introduction Regular cycling has been shown to improve health and well-being and has a role in tackling obesity and inactivity. Cycle collisions, particularly those involving motorised vehicles, can lead to significant mortality and morbidity and are currently a barrier to wider uptake of cycling. There is evidence that the conspicuity of cyclists may be a factor in some injury collisions. Low-cost, easy to use retro-reflective and fluorescent clothing and accessories (’conspicuity aids’) are widely available. Their effectiveness in reducing the risk of cycling collisions is currently unknown. This study was designed to investigate the relationship between the use of conspicuity aids and risk of collision or evasion crashes for utility and commuter cyclists in an urban setting in the UK. Methods A matched case-control study was undertaken. Cases were adult commuter and utility cyclists who were involved in a crash resulting from a collision or attempted evasion of a collision with another road user. Cases were recruited at a large UK emergency department. Controls were commuter and utility cyclists matched by time and day of travel, season and geographical area of cycling. Controls were recruited at public and private cycle parking sites. Data on the use of conspicuity aids, crash circumstances, participant demographics, cycling experience, safety equipment use and journey characteristics including an estimate of the bicycle crash risk for each chosen route (the number of previous crashes per 100 million kilometres travelled by bicycle calculated for each participant route) were collected using self-completed questionnaires and maps. Conditional logistic regression was used to calculate crude and adjusted odds ratios and 95% confidence intervals of the risk of a crash involving a collision or evasion of a collision with another road user when cyclists reported they were using any item of fluorescent or retro-reflective clothing or equipment vs. none. Unconditional logistic regression was used to analyse associations between participant characteristics and conspicuity aid use. Continuous variables were dichotomised where there was a non-linear relationship to the bicycle crash outcome variable or the primary exposure variable. The sensitivity of the study models to selection, recall and information biases and the effect of missing data was assessed using independent records of conspicuity aid use by potential participants during recruitment. Observations of conspicuity aid use within the study source population at sites across the study catchment area were also conducted by the researcher during the recruitment phase. Results There were 76 cases and 272 controls cyclists who were eligible for inclusion in the primary analysis (response rate of 13% and 54% respectively). The proportion of cases who reported using any item of fluorescent or reflective materials on their clothing or equipment (excluding bicycle mounted reflectors) was higher than for matched controls (cases users 69.7%; 95% CI 58.1% to 79.8% vs. control users 65.4%; 95% CI 59.5% to 79.1%). The unadjusted odds ratio for a collision or evasion crash when using conspicuity aids, was 1.2 (95% CI 0.66 to 2.17). Two alternative modelling strategies were employed. After adjustment for confounding from age, gender, socio-economic deprivation, number of years of cycling experience, bicycle crash risk along each route and cycle helmet use the odds ratio was 1.77 (95% CI 0.74 to 4.25). After adjustment for confounding from age, gender, socio-economic deprivation, bicycle crash risk along each route and history of previous cycle crash involvement the odds ratio was 2.4 (95% CI 1.06 to 5.7). The odds ratio was not significantly affected by adjustment for possession of a driving licence, reported bicycle safety training in childhood, psychometric associates of risk taking behaviour, cycle helmet wearing, years of experience of cycling, distance or number of trips cycled in the previous seven days, type of bicycle, the use of bike-mounted lights or reflectors, weather or lighting conditions, familiarity with the route or alcohol consumption within 8 hours prior to the recorded journey. There was a significant difference between the measure of bicycle crash risk along each route for cases and controls with controls reporting travelling on routes with lower objective bicycle crash risk (median (IQR); cases 378.5 (232.4 to 548.3) vs. controls 268.5 (192.6 to 464.5); p= 0.006). There were no significant differences in route risk for users vs. non-users of conspicuity aids (route risk median (IQR) for conspicuity aid users vs. non-users; 308.1 (198.0 to 504.3) vs. 272.3 (203.7 to 413.4; p= 0.22). Conspicuity aid use was associated with increased length of participant route (unadjusted OR 3.25 for reported route greater than median; 95% CI 2.04 to 5.17 p<0.001), higher numbers of police-recorded bicycle crashes (unadjusted OR 2.26 for greater than median; 95% CI 1.43 to 3.55; p<0.001) and lower numbers of observed cyclists on each route (unadjusted OR 0.999; 95% CI 0.998 to 1.000 p=0.015). Route risk data were missing for 50 participants (15 cases and 35 controls). Validation of the primary exposure showed that there was moderate agreement between participants’ self-reports and independently collected data (kappa 0.42; 95% CI 0.32 to 0.51) but independent data were collected on only 4 eligible cases. Self-reported use of conspicuity aids was higher amongst cases and controls in this study than that observed for cyclists in the study area during the recruitment period (23%; 95% CI 22% to 24%). Discussion The results of this study show a non-significant increase in the odds of a crash for users compared to non-users of conspicuity aids whilst cycling. This association was increased after adjustment for confounders but most models generated to adjust for confounding remained insignificant. No reduction in crash risk could be demonstrated. This is not consistent with the large body of evidence suggesting that conspicuity aids increase the distances from which wearers can be detected and recognised by drivers in a variety of settings. There was evidence that cases were cycling along routes with greater exposure to traffic danger than controls although there were many participants with missing data for this variable potentially introducing a further source of bias. The route risk estimates did not vary significantly between conspicuity aid users and non-users. Residual confounding may have occurred if conspicuity aid users were taking more risks when encountering similar traffic conditions to non-users. This could not be measured but may go some way to explaining these results. If cyclists over-estimate the likely effect of their conspicuity aid use this could result in over compensation and a net increase in crash risk. Adjustment for route risk may have introduced bias by the loss of some participants from the analysis or by acting as a positive suppressor variable increasing the influence of uncontrolled confounding if conspicuity aid use were leading to risky riding over and above the objective risk arising from differing road and traffic conditions. The association between the odds of crash and travelling on roads with higher incidences of previous cycle crashes and fewer cyclists provides support for the “safety in numbers” effect reported in other studies. Differential selection and misclassification biases may also have resulted in over representation of conspicuity aid users amongst cases compared to controls. Social expectation from involvement in a collision crash may have resulted in cases who were not using conspicuity aids being less likely to participate than controls who were non-users. For similar reasons cases may have been more inclined to over-estimate their conspicuity aid use than controls.

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.

Railway level crossing collisions in Australia are a major cause of concern for both rail and road authorities. Despite the fact that the number of railway crash fatalities in Australia has fallen in recent years, level crossing collisions constitute a significant proportion of the national rail toll. Although rail transport is presently one of the safest forms of land transport, collisions at level crossings are three times more likely to involve fatalities as compared to all other types of road crashes (Afxentis, 1994). With many level crossing fatalities and injuries resulting in coronial inquests, litigation and negative media publicity, the actions of rail and road infrastructure providers and the behaviour of motorists, pedestrians and rail users, come under close scrutiny. Historically, research in this area has been plagued by the rail/road interface and the separation of responsibilities between rail and road authorities reflecting the social and political context in which they are contained. With the recent rail reform in Australia, safety at level crossings has become a key priority area. Accordingly, there is a need to better understand the scope and nature of motorist behaviour at level crossings, in order to develop and implement more effective countermeasures for unsafe driving behaviour. However, a number of obstacles have hindered research into the area of level crossing safety. As with many road crashes, the contributing causes and factors are often difficult to determine, however a recent investigation of fatal collisions at level crossings supports the notion that human fault is a major contributor (Australian Transport Safety Bureau, 2002a). Additionally, there is a lack of reliable data available relating to the behavioural characteristics and perceptions of drivers at level crossings. Studies that do exist have lacked a strong theoretical base to guide the interpretation of results. Due to the lack of financial viability of continuing to approach risk management from an engineering perspective, the merits of human factor research need to be examined for suitability. In Australia, there has been considerable recognition regarding the importance of human factor approaches to level crossing safety (Australian Transport Council, 2003). However, little attempt has been made by authorities to scientifically develop and measure the effectiveness of road safety educational interventions. Therefore, there exists a significant need for developing targeted road safety educational interventions to improve current risk management solutions at level crossings. This research program is the first of its kind in investigating motorist behaviour at level crossings and the measuring the effectiveness of educational interventions for improving driving safety. Although other ‘educational’ campaigns exist in this field, no campaign or intervention has been guided by empirical research or theory. This thesis adopted a multidisciplinary approach to theory, reviewing perspectives from psychology, sociology and public health to explain driver behaviour at level crossings. This array of perspectives is necessary due to the variety of behaviours involved in collisions and near-misses at level crossings. The motivation underlying motorist behaviour determines to a large extent how successful behaviour change strategies (e.g. educational interventions) may be. Fishbein’s Integrated Model of Behaviour Change (IM) based largely on the health belief model, theory of reasoned action and theory of planned behaviour (Fishbein, 2000), assisted in the planning and development of a ‘oneoff’ targeted educational intervention specific for three different road user groups and in questionnaire development to ascertain the present context of motorist behaviour at level crossings. As no known research has been conducted that utilizes any psychosocial model to explain or predict level crossing behavior within different road user groups, this research program used this model as an exploratory tool rather than a tool to asses the model’s capacity in explaining such behaviour. The difference between this model and others is the inclusion of two important constructs in driving: skills (or abilities) and environmental factors. Fishbein (2003) suggests that the model recognises the lack of skills (or abilities) and/or environmental constraints may prevent a person from acting on their intentions, in light of the fact that intention is viewed as the primary determinant of behaviour. While the majority of behaviour change theories are limited by a range of conceptual and contextual factors (Parker, 2004), the IM was used to assist this research program as it appeared to be the most applicable model to examining level crossing safety. A variety of data collection methods were used in this research program as much of what is currently known about level crossing collisions is derived from coroner’s findings and statistics. The first study (Study One) was designed to extend this knowledge by undertaking a more thorough examination of contributing factors to level crossing crashes and the road user groups at risk. This study used the method of ‘triangulation’ (i.e. combining research methods to give a range of perspectives) whereby both qualitative (focus groups) and quantitative (modified Delphi technique) research designs were utilised (Barbour, 1999, Bryman, 1992). With the discipline of road safety research requiring methodological strategies that will enhance efforts to conceptualise the multi-faceted nature of motorist behaviour at level crossings, this application provided the robustness required. Results from the Delphi technique indicated that older, younger and heavy vehicle drivers are considered to be three of the highest risk road user groups by experts in the field. For the older driver group, experts agreed that errors in judgment were the most important issue for this group when driving at level crossings. Risk taking by younger drivers, such as trying to beat the train across the crossing, was viewed as the central issue for the younger driver group. Like the younger driver group, a concern by experts with the heavy vehicle group was intentional risk taking at level crossings. However, experts also rated the length of heavy vehicles a major concern due to the possibility of a truck over-hanging a crossing. Results from focus groups with train drivers in Study One indicated that there are unique problems associated with crossings in rural/regional areas compared to urban areas. The metropolitan train drivers generally experienced motorist behaviour at active crossings with flashing lights and boom gates while the regional train drivers experienced behaviours at active crossings with boom gates, crossings with lights only and passive crossings with stationary signs. In the metropolitan train driver group, experiences of motorist behaviour at level crossings included: motorists driving around boom gates, getting stuck under boom gates, queuing over congested crossings and driving through the crossing after the red lights commence flashing. The behaviour of motorists driving around boom gates was noted to occur quite regularly. The majority of metropolitan train drivers reported that it was a common occurrence for motorists to drive through a crossing when the lights are flashing both before and after the booms were activated and some crossings were named as ‘black spots’ (locations where motorists repeatedly violate the road rules). Vehicles protruding into the path of the train and motorists entering congested crossings and then panicking and driving backwards into the boom gates were also mentioned. Regional train drivers indicated that motorists not stopping or giving way to trains is a continual problem at passively controlled crossings (i.e. no boom gates or flashing lights). Regional train drivers generally agreed that the majority of motorists obey protection systems; however some motorists drive through flashing lights or drive around boom gates. Other high risk behaviours included motorists attempting to beat the train across the crossing, speeding up to go through flashing lights, and general risk taking by younger drivers in particular. Motorists not allowing enough time to cross in front of the train or hesitating (stopstarting) at crossings were also noted to be at high risk. There was a general perception by regional train drivers that motorists are unable to judge the speed and distance of an approaching train to determine a safe gap during which to cross. Local motorists were also reported to be a problem at level crossings for regional train drivers. A theme common to regional and metropolitan train drivers was the risk of catastrophic consequence associated with level crossing collisions. The reasons given for this were the threat of derailment, serious property damage, the high risk of a fatality, personal injury and, most earnestly, the potential for enduring psychological consequences. Drivers uniformly spoke about the continual fear they had of being involved in a collision with a heavy vehicle, and many spoke of the effects that such collisions had on train drivers involved. For this reason, train drivers were said to consider any near-miss incident involving trucks particularly serious. The second study undertaken as part of this research program (Study Two), involved formative research as part of the planning, development and delivery of behavioural interventions for each of the three road user groups identified in Study One. This study also used both qualitative and quantitative data collection methods to provide methodological triangulation and ensure reliability of the data. The overall objective of the qualitative data collection was to obtain rich data using a qualitative mode of inquiry, based on the key variables of attitudes, norms, self-efficacy (perceived behavioural control), perceived risk, environmental constraints and the skills/abilities of drivers. The overall objective of the quantitative data collection was to prioritise the issues identified in order to direct and allocate project resources for intervention planning, development and delivery. This combined recruitment strategy was adopted as it was an appropriate and practical data collection strategy within the qualitative and exploration methodology. Information obtained from each of the groups was critical in assisting, guiding, and identifying priority areas for message and material development. The use of focus groups and one-on-one interviews provided insights into why drivers think or do what they do at level crossings. The qualitative component of this study found that for the older driver group, regional drivers hold a greater perception of risk at level crossings than urban older drivers, with many recalling near-misses. Participants from the urban older driver group indicated that level crossings are not as dangerous as other aspects of driving, with many participants being doubtful that motorists are killed while driving at level crossings. Both urban and regional younger drivers tended to hold a low perception of risk for driving at level crossings, however many participants reported having great difficulty in judging the distance a train is from a crossing. Impatience for waiting at level crossings was reported to be the major reason for any risk taking at level crossings in the younger driver group. Complacency and distraction were viewed by heavy vehicle participants as two of the major driver factors that put them at risk at level crossings, while short-stacking (when the trailer of the truck extends onto the crossing), angle of approach (acute or obtuse angle) and lack of advance warning systems were seen as the major engineering problems for driving a truck at level crossings. The quantitative component of this study involving research with train drivers found that at the aggregate train driver level, it is apparent that train drivers consider motorists’ deliberate violations of the road rules and negligently lax approach to hazard detection as the predominant causes of dangerous driving at level crossings. Experts were observed to rank risk taking behaviours slightly lower than train drivers, although they agreed with train drivers that ‘trying to beat the train’ is the single most critical risk taking behaviour observed by motorists. The third study (Study Three) involved three parts. The aim of Part One of this study was to develop targeted interventions specific to each of the three road user groups by using Fishbein’s theoretical model (Integrated Model of Behaviour Change) as a guide. The development of interventions was originally seen as being outside of the scope of this project, however it became intertwined in questionnaire development and thus deemed to be within the realms of the current mode of inquiry. The interventions were designed in the format of a pilot radio road safety advertisement, as this medium was found to be one of the most acceptable to each of the road user groups as identified in the formative research undertaken in Study Two. The interventions were used as a ‘one-off’ awareness raising intervention for each road user group. Part Two involved the investigation of the present context of unsafe driving behaviour at level crossings. This second part involved the examination of the present context of motorist behaviour at level crossings using key constructs from Fishbein’s Integrated Model of Behaviour Change (IM). Part Three involved trialing a pilot road safety radio advertisement using an intervention and control methodology. This part investigated the changes in pre and post-test constructs including intentions, self-reported behaviour, attitudes, norms, selfefficacy/ perceived behaviour control, perceived risks, environment constraints and skills/ability. Results from this third study indicated that younger drivers recognise that level crossings are potentially a highly dangerous intersection yet are still likely to engage in risk taking behaviours. Additionally, their low levels of self-efficacy in driving at level crossings pose challenges for developing interventions with this age group. For the older driver sample, this research confirms the high prevalence of functional impairments such as increasing trouble adjusting to glare and night-time driving, restricted range of motion to their neck and substantial declines in their hearing. While factors contributing to the over-representation of older drivers in collisions at level crossings are likely to be complex and multi-faceted, such functional impairments are expected to play a critical role. The majority of heavy vehicle drivers reported driving safely and intending to drive safely in the future, however, there is a sub-set of drivers that indicate they have in the past and will in the future take risks when traversing crossings. Although this sub-set is relatively small, if generalised to the larger trucking industry it could be problematic for the rail sector and greater public alike. Familiarity was a common factor that was found to play a role in driving intention at level crossings for all three road user groups. This finding supports previous research conducted by Wigglesworth during the 1970’s in Australia (Wigglesworth, 1979). Taken together, the results of the three studies in this research program have a number of implications for level crossing safety in Australia. Although the ultimate goal to improve level crossing safety for all motorists would be to have a combination of engineering, education and enforcement countermeasures, the small number of fatalities in comparison to the national road toll limits this. It must be noted though that the likelihood of creating behavioural change would be increased if risk taking at level crossings by all motorists was detected and penalised, or alternatively, if perceptions of such detection were increased. The instilling of fear in drivers with the threat of punishment via some form of sanction can only be achieved through a combination of a mass media campaign and increasing police presence. Ideally, the aim would be to combine fear of punishment with the guilt associated with the social non-acceptability of disobeying road rules at level crossings. Such findings have direct implications for improving the present context of motorist behaviour at level crossings throughout Australia.

Railway level crossing collisions in Australia are a major cause of concern for both rail and road authorities. Despite the fact that the number of railway crash fatalities in Australia has fallen in recent years, level crossing collisions constitute a significant proportion of the national rail toll. Although rail transport is presently one of the safest forms of land transport, collisions at level crossings are three times more likely to involve fatalities as compared to all other types of road crashes (Afxentis, 1994). With many level crossing fatalities and injuries resulting in coronial inquests, litigation and negative media publicity, the actions of rail and road infrastructure providers and the behaviour of motorists, pedestrians and rail users, come under close scrutiny. Historically, research in this area has been plagued by the rail/road interface and the separation of responsibilities between rail and road authorities reflecting the social and political context in which they are contained. With the recent rail reform in Australia, safety at level crossings has become a key priority area. Accordingly, there is a need to better understand the scope and nature of motorist behaviour at level crossings, in order to develop and implement more effective countermeasures for unsafe driving behaviour. However, a number of obstacles have hindered research into the area of level crossing safety. As with many road crashes, the contributing causes and factors are often difficult to determine, however a recent investigation of fatal collisions at level crossings supports the notion that human fault is a major contributor (Australian Transport Safety Bureau, 2002a). Additionally, there is a lack of reliable data available relating to the behavioural characteristics and perceptions of drivers at level crossings. Studies that do exist have lacked a strong theoretical base to guide the interpretation of results. Due to the lack of financial viability of continuing to approach risk management from an engineering perspective, the merits of human factor research need to be examined for suitability. In Australia, there has been considerable recognition regarding the importance of human factor approaches to level crossing safety (Australian Transport Council, 2003). However, little attempt has been made by authorities to scientifically develop and measure the effectiveness of road safety educational interventions. Therefore, there exists a significant need for developing targeted road safety educational interventions to improve current risk management solutions at level crossings. This research program is the first of its kind in investigating motorist behaviour at level crossings and the measuring the effectiveness of educational interventions for improving driving safety. Although other ‘educational’ campaigns exist in this field, no campaign or intervention has been guided by empirical research or theory. This thesis adopted a multidisciplinary approach to theory, reviewing perspectives from psychology, sociology and public health to explain driver behaviour at level crossings. This array of perspectives is necessary due to the variety of behaviours involved in collisions and near-misses at level crossings. The motivation underlying motorist behaviour determines to a large extent how successful behaviour change strategies (e.g. educational interventions) may be. Fishbein’s Integrated Model of Behaviour Change (IM) based largely on the health belief model, theory of reasoned action and theory of planned behaviour (Fishbein, 2000), assisted in the planning and development of a ‘oneoff’ targeted educational intervention specific for three different road user groups and in questionnaire development to ascertain the present context of motorist behaviour at level crossings. As no known research has been conducted that utilizes any psychosocial model to explain or predict level crossing behavior within different road user groups, this research program used this model as an exploratory tool rather than a tool to asses the model’s capacity in explaining such behaviour. The difference between this model and others is the inclusion of two important constructs in driving: skills (or abilities) and environmental factors. Fishbein (2003) suggests that the model recognises the lack of skills (or abilities) and/or environmental constraints may prevent a person from acting on their intentions, in light of the fact that intention is viewed as the primary determinant of behaviour. While the majority of behaviour change theories are limited by a range of conceptual and contextual factors (Parker, 2004), the IM was used to assist this research program as it appeared to be the most applicable model to examining level crossing safety. A variety of data collection methods were used in this research program as much of what is currently known about level crossing collisions is derived from coroner’s findings and statistics. The first study (Study One) was designed to extend this knowledge by undertaking a more thorough examination of contributing factors to level crossing crashes and the road user groups at risk. This study used the method of ‘triangulation’ (i.e. combining research methods to give a range of perspectives) whereby both qualitative (focus groups) and quantitative (modified Delphi technique) research designs were utilised (Barbour, 1999, Bryman, 1992). With the discipline of road safety research requiring methodological strategies that will enhance efforts to conceptualise the multi-faceted nature of motorist behaviour at level crossings, this application provided the robustness required. Results from the Delphi technique indicated that older, younger and heavy vehicle drivers are considered to be three of the highest risk road user groups by experts in the field. For the older driver group, experts agreed that errors in judgment were the most important issue for this group when driving at level crossings. Risk taking by younger drivers, such as trying to beat the train across the crossing, was viewed as the central issue for the younger driver group. Like the younger driver group, a concern by experts with the heavy vehicle group was intentional risk taking at level crossings. However, experts also rated the length of heavy vehicles a major concern due to the possibility of a truck over-hanging a crossing. Results from focus groups with train drivers in Study One indicated that there are unique problems associated with crossings in rural/regional areas compared to urban areas. The metropolitan train drivers generally experienced motorist behaviour at active crossings with flashing lights and boom gates while the regional train drivers experienced behaviours at active crossings with boom gates, crossings with lights only and passive crossings with stationary signs. In the metropolitan train driver group, experiences of motorist behaviour at level crossings included: motorists driving around boom gates, getting stuck under boom gates, queuing over congested crossings and driving through the crossing after the red lights commence flashing. The behaviour of motorists driving around boom gates was noted to occur quite regularly. The majority of metropolitan train drivers reported that it was a common occurrence for motorists to drive through a crossing when the lights are flashing both before and after the booms were activated and some crossings were named as ‘black spots’ (locations where motorists repeatedly violate the road rules). Vehicles protruding into the path of the train and motorists entering congested crossings and then panicking and driving backwards into the boom gates were also mentioned. Regional train drivers indicated that motorists not stopping or giving way to trains is a continual problem at passively controlled crossings (i.e. no boom gates or flashing lights). Regional train drivers generally agreed that the majority of motorists obey protection systems; however some motorists drive through flashing lights or drive around boom gates. Other high risk behaviours included motorists attempting to beat the train across the crossing, speeding up to go through flashing lights, and general risk taking by younger drivers in particular. Motorists not allowing enough time to cross in front of the train or hesitating (stopstarting) at crossings were also noted to be at high risk. There was a general perception by regional train drivers that motorists are unable to judge the speed and distance of an approaching train to determine a safe gap during which to cross. Local motorists were also reported to be a problem at level crossings for regional train drivers. A theme common to regional and metropolitan train drivers was the risk of catastrophic consequence associated with level crossing collisions. The reasons given for this were the threat of derailment, serious property damage, the high risk of a fatality, personal injury and, most earnestly, the potential for enduring psychological consequences. Drivers uniformly spoke about the continual fear they had of being involved in a collision with a heavy vehicle, and many spoke of the effects that such collisions had on train drivers involved. For this reason, train drivers were said to consider any near-miss incident involving trucks particularly serious. The second study undertaken as part of this research program (Study Two), involved formative research as part of the planning, development and delivery of behavioural interventions for each of the three road user groups identified in Study One. This study also used both qualitative and quantitative data collection methods to provide methodological triangulation and ensure reliability of the data. The overall objective of the qualitative data collection was to obtain rich data using a qualitative mode of inquiry, based on the key variables of attitudes, norms, self-efficacy (perceived behavioural control), perceived risk, environmental constraints and the skills/abilities of drivers. The overall objective of the quantitative data collection was to prioritise the issues identified in order to direct and allocate project resources for intervention planning, development and delivery. This combined recruitment strategy was adopted as it was an appropriate and practical data collection strategy within the qualitative and exploration methodology. Information obtained from each of the groups was critical in assisting, guiding, and identifying priority areas for message and material development. The use of focus groups and one-on-one interviews provided insights into why drivers think or do what they do at level crossings. The qualitative component of this study found that for the older driver group, regional drivers hold a greater perception of risk at level crossings than urban older drivers, with many recalling near-misses. Participants from the urban older driver group indicated that level crossings are not as dangerous as other aspects of driving, with many participants being doubtful that motorists are killed while driving at level crossings. Both urban and regional younger drivers tended to hold a low perception of risk for driving at level crossings, however many participants reported having great difficulty in judging the distance a train is from a crossing. Impatience for waiting at level crossings was reported to be the major reason for any risk taking at level crossings in the younger driver group. Complacency and distraction were viewed by heavy vehicle participants as two of the major driver factors that put them at risk at level crossings, while short-stacking (when the trailer of the truck extends onto the crossing), angle of approach (acute or obtuse angle) and lack of advance warning systems were seen as the major engineering problems for driving a truck at level crossings. The quantitative component of this study involving research with train drivers found that at the aggregate train driver level, it is apparent that train drivers consider motorists’ deliberate violations of the road rules and negligently lax approach to hazard detection as the predominant causes of dangerous driving at level crossings. Experts were observed to rank risk taking behaviours slightly lower than train drivers, although they agreed with train drivers that ‘trying to beat the train’ is the single most critical risk taking behaviour observed by motorists. The third study (Study Three) involved three parts. The aim of Part One of this study was to develop targeted interventions specific to each of the three road user groups by using Fishbein’s theoretical model (Integrated Model of Behaviour Change) as a guide. The development of interventions was originally seen as being outside of the scope of this project, however it became intertwined in questionnaire development and thus deemed to be within the realms of the current mode of inquiry. The interventions were designed in the format of a pilot radio road safety advertisement, as this medium was found to be one of the most acceptable to each of the road user groups as identified in the formative research undertaken in Study Two. The interventions were used as a ‘one-off’ awareness raising intervention for each road user group. Part Two involved the investigation of the present context of unsafe driving behaviour at level crossings. This second part involved the examination of the present context of motorist behaviour at level crossings using key constructs from Fishbein’s Integrated Model of Behaviour Change (IM). Part Three involved trialing a pilot road safety radio advertisement using an intervention and control methodology. This part investigated the changes in pre and post-test constructs including intentions, self-reported behaviour, attitudes, norms, selfefficacy/ perceived behaviour control, perceived risks, environment constraints and skills/ability. Results from this third study indicated that younger drivers recognise that level crossings are potentially a highly dangerous intersection yet are still likely to engage in risk taking behaviours. Additionally, their low levels of self-efficacy in driving at level crossings pose challenges for developing interventions with this age group. For the older driver sample, this research confirms the high prevalence of functional impairments such as increasing trouble adjusting to glare and night-time driving, restricted range of motion to their neck and substantial declines in their hearing. While factors contributing to the over-representation of older drivers in collisions at level crossings are likely to be complex and multi-faceted, such functional impairments are expected to play a critical role. The majority of heavy vehicle drivers reported driving safely and intending to drive safely in the future, however, there is a sub-set of drivers that indicate they have in the past and will in the future take risks when traversing crossings. Although this sub-set is relatively small, if generalised to the larger trucking industry it could be problematic for the rail sector and greater public alike. Familiarity was a common factor that was found to play a role in driving intention at level crossings for all three road user groups. This finding supports previous research conducted by Wigglesworth during the 1970’s in Australia (Wigglesworth, 1979). Taken together, the results of the three studies in this research program have a number of implications for level crossing safety in Australia. Although the ultimate goal to improve level crossing safety for all motorists would be to have a combination of engineering, education and enforcement countermeasures, the small number of fatalities in comparison to the national road toll limits this. It must be noted though that the likelihood of creating behavioural change would be increased if risk taking at level crossings by all motorists was detected and penalised, or alternatively, if perceptions of such detection were increased. The instilling of fear in drivers with the threat of punishment via some form of sanction can only be achieved through a combination of a mass media campaign and increasing police presence. Ideally, the aim would be to combine fear of punishment with the guilt associated with the social non-acceptability of disobeying road rules at level crossings. Such findings have direct implications for improving the present context of motorist behaviour at level crossings throughout Australia.

The concept of involving the public in the development of transportation solutions was built in the Federal-Aid Highway Act of 1956, the legislation that authorized the construction of the Interstate Highway System. Better plans, transparent process, and public support are some of the benefits that road managers can obtain by educating and involving the general public. During the last two decades the volume of research performed related to the topic of customer-driven highway maintenance suggests an increasing level of interest in the field. Most research concentrates on gathering information from road users to assess the performance level of highways. However, public opinion can also be collected for measuring the quality of the service delivered by maintenance units. Assessing product and service delivery performance is important for determining the overall performance of highway maintenance programs. The present study examines the relationship between road users' overall perceptions of the quality of highway maintenance services and the variables that define the highway maintenance service quality domain. The results of the study indicate that two service dimensions, Safety and Reliability, explain about half of the variance in overall perceptions of highway maintenance service quality. The procedures developed for the study provide an initial step for further improvement of the highway maintenance service quality measurement.
Ph. D.

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.

Planläggning av cirkulationsplatser har blivit ett vanligt inslag i en mängd olika städer världen över för att lösa farliga situationer som kan uppstå i traditionella fyrvägskorsningar. Detta eftersom bilisternas hastighet hålls låg i en cirkulationsplats jämfört med en vanlig fyrvägskorsning vilket i sin tur leder till mindre allvarliga olyckor. Är de oskyddade trafikanternas säkerhetsfördelar vid en cirkulationsplats lika tydliga? Syftet med studien är att undersöka utformningen av trafikmiljöer, med fokus på fotgängares och cyklisters säkerhet i anslutning till cirkulationsplatser. Jag har sett på vilka säkerhetshöjande aspekter som bör tas i beaktande för oskyddade trafikanter. Frågeställningarna i arbetet är - Vilka för- och nackdelar för oskyddade trafikanter finns det med planläggning och konstruktion av cirkulationsplatser? - Vilka säkerhetsaspekter tas i beaktande vid cirkulationsplatser? Forskningen baserar sig på en kvalitativ metod. Datainsamlingsmetoder som använts är observation, intervju och kvalitativ textanalys. I undersökningen deltog tre planerare från Gävle, Eskilstuna och Västerås. I undersökningen lyfts säkerhetsaspekter, samt för- och nackdelar fram som de undersökta kommunerna utgår ifrån i planläggningen av cirkulationsplatser och övergångsställen. I resultatet kan konstateras att det med snabba och relativt enkla metoder och åtgärder är möjligt att förbättra fotgängares och cyklisters säkerhet på passager vid cirkulationsplatser.
Planning of roundabouts have become a common feature in various cities around the world to resolve dangerous situations that may occur in traditional four-way intersections. This is because the motorists’ speed is lower in a roundabout compared to a standard four-way intersection, which leads to less severe accidents. Are vulnerable road users safety benefits at a roundabout as clear? The purpose of the study is to examine the design of traffic environments, with a focus on pedestrian and cyclists’ safety in connection to roundabouts. I have seen on the safety aspects that should be taken into consideration for pedestrians and cyclists. The research questions in my study are: - What are the advantages and disadvantages of vulnerable road users with planning and construction of roundabouts? - Which safety aspects are taken into consideration in roundabouts? The research is based on a qualitative approach. Data collection methods used are observation, interview and qualitative text analysis. The study included three planners from Gävle, Eskilstuna and Västerås. The highlighted safety aspects, advantages and disadvantages presented by the surveyed municipalities proceed from with planning of roundabouts and pedestrian crossings. In the result it can be stated that with fast and relatively simple methods and steps are possible to improve pedestrian and cyclist safety on crossings at roundabouts.

 

This study is an analysis of the traffic situation for pedestrians and bicyclist, unprotected road users, in Accra’s Central Business District. A Swedish method, Calm streets, is used to identify conflicts in the mixed traffic situation. The findings reveal a large amount of conflicts between unprotected road users and motor vehicles. These conflicts cause congestions which have negative implications on the environment, health and economy.

In addition an assessment of the quality of and access to pedestrian and bicycle facilities were conducted. This assessment indicates that the quality and access to the facilities are in general low, especially for the disabled, elderly and children. A larger Traffic Network Analysis and a Cost Benefit Analysis are needed to address these problems for stakeholders and decision makers.

 

This diploma thesis deals with children‘s reaction time. The theoretical part of this work describes children as vulnerable road users and discusses methods of measuring reaction time. The practical part presents some realized experiments refer to the children’s reaction time and their results evaluation.

The aim of this work is to evaluate current procedures and to refine assessment of impact connected to the drivers' age and traffic accidents. The theoretical part describes senior drivers, traffic accident rate of seniors and decreased ability to drive influenced by age. The practical part is case report of traffic accidents caused by senior drivers, measuring reaction time and the evaluation of these measurements. I have developed some proposals for seniors to prevent the risk of the occurrence of traffic accidents.

The growing population and motorization generate more movements. In many cities, the increase of population and motorization is much greater than the development of the capacity of the transportation network. For unprotected road users, the risk of getting in a traffic accident increases and the risk of being more severely injured in an accident. In March 2020, a pandemic was declared because of a Coronavirus. More people started to work/study from home to prevent the virus from spreading by avoiding unnecessary trips, gatherings, and crowded areas. Therefore, travel behaviours have shifted during the pandemic compared to previous years. This project aims to get knowledge of how mobility and traffic accidents are affected by significant shifts of travel flow, predict the effect of traffic accidents based on mobility, and evaluate the risk of travelling on a particular road segment.

Examensarbetet är utfört vid Institutionen för teknik och naturvetenskap (ITN) vid Tekniska fakulteten, Linköpings universitet

Driving is a complex dynamic task. As the car driver drives along a route they have to adjust their driving technique in accordance with the traffic level, infrastructure and environment around them. The amount of information in the environment would be overwhelming were it not for the presence of stored mental templates, accumulated through training and experience, which become active when certain features are encountered. Problems occur when the environment triggers the incorrect templates, or fails to trigger the correct templates. Problems like these can be overcome by adopting a “self-explaining” (SER) approach to road design. That is to say, purposefully designed roads which trigger correct behaviour. A concept which can help improve the theoretical robustness of the SER approach is Situation Awareness (SA). SA describes how the environment and mental templates work together to ensure drivers remain coupled to the dynamics of their situation. It is a widely researched concept in the field of Human Factors but not in the domain of Self-Explaining Roads (SER), despite the very obvious conceptual overlaps. This thesis, for the first time, blends the two approaches, SA and SER, together. From this the ability to extract cognitively salient features and ability to enhance driving behaviour and their effects on driving behaviour are sufficiently enhanced. After establishing SA as critical to driving through literature review the experiment phase started with determining the source of driver SA. Road environment was found to be of utmost importance for feeding into driver SA. This was also confirmed with the results of the on-road exploratory study. The success of the exploratory study led to large scale naturalistic study. It provided data on driver mental workload, subjective situation awareness, speed profile and endemic feature. Endemic features are unique characteristics of a road which make a road what it is. It was found that not all endemic features contribute to SA of a road system. Therefore through social network analysis list of cognitive salient features were derived. It is these cognitive salient features which hold compatible SA and facilitate SA transaction in a road system. These features were found to reduce speed variance among drivers on a road. The thesis ends by proposing a ‘road drivability tool’ which can predict potentially dangerous zones. Overall, the findings contribute to new imaginative ways road design in order to maximize safety and efficiency.

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.

One of the major barriers to implementation of road user charging is how to design a scheme that is simultaneously acceptable to the public and effective in achieving its objective. The aim of this research was to study how road user charging can be designed to achieve acceptability and effectiveness. Acceptability was reflected by voting behaviour, in which individuals were asked whether they were willing to vote for charging schemes. Effectiveness in reducing congestion was evaluated by mode switching of commuters. The research demonstrated the effects of the system benefits (car and bus travel time reduction, environmental improvement and revenue use) and the system features (charging levels, charging methods, charged times and charged areas). It also investigated the impacts of personal characteristics and perceptions. The research also examined the effect of selfish and social perspectives, reflected by the perceptions of benefits to self and to society, on acceptability. Paper based SP questionnaires were distributed to residents and employees in Leeds and London between November 2000 and March 2001. A total of 830 responses were received. The analysis technique was based on random utility theory, which was used to formulate the multinomial-logit based models. The standard logit model was used to demonstrate the overall effects of variables for the whole sample. The segmentation model, based on the incremental factors, was used to identify the different effects for different groups of people. The random parameters logit model was used to examine taste variations (heterogeneity) among individuals frorn unobserved factors, which were unable to be captured by the segmentation model. The study found that although more highly effective charging schemes (with higher levels of charge) were less acceptable, while more highly acceptable schemes (with lower levels of charge) were not substantially less effective. In other words, effective charging schemes were not always unacceptable. Acceptability varies substantially across system characteristics. Acceptable road user charging schemes can be designed by limiting the area of charge to within the city centre and having a fixed charge per day. Support would be increased significantly if the scheme was expected to bring substantial environmental improvement. Over 50% of people would vote for this scheme, if the charging level is less than £3 per day in Leeds, and less than £7 per day in London. Effectiveness in reducing car use had a small variation across the factors. Overall, any charging system is relatively effective in reducing car commuting. Even at £l per day, over 20% of car commuters in Leeds and about 30% in London would switch to non-car modes or uncharged times. When the charge rises to £7 per day, the reductions would increase to around 40%. A small number of non-car users would change to use cars because of car delayed-time reductions. The acceptability and effectiveness can be improved by provision of clear information on the principles and objectives of charging, on the severity of congestion and pollution, on the adverse effects of car use, and on the effectiveness of road user charging in reducing the problems. In addition, individuals need to be convinced that road user charging will provide benefits both to themselves and to society as a whole. In brief, this research suggests that the relationship between acceptability and effectiveness of road user charging schemes is not high. It is not simply the case that highly effective schemes are less acceptable. Road user charging can be designed to achieve high acceptability and effectiveness.

Road traffic accidents are common sources of trauma experienced by adults, adolescents, and children. Trauma may arise as a direct result of physical injury, may occur due to experiencing perceived threat to one's life or physical self, or may develop due to witnessing death or injury to others. While there has been growing interest in the development of psychological distress, including post-traumatic stress disorder (PTSD), phobias, and adjustment disorder, among survivors of road accidents, there has been no systematic investigation of cyclists involved in road accidents and little specific research into child and adolescent road accident victims. In regard to cyclists, the first of these under-researched groups, study one investigated the occurrence of psychological distress in New Zealand adult cycling victims. In 1999, 619 cyclists were injured on New Zealand roads, with 86 of these accident victims from the Christchurch region. A sample of 27 Christchurch adult cyclists, who had been involved in an accident with a motor vehicle, at least one month prior to the interview, completed a structured interview and number of questionnaires. Results indicated that one third of the participants suffered ongoing psychological distress following their accident. Implications for mental health, personal wellbeing, and potential costs to the community are discussed. Study two examined the occurrence of psychological distress in New Zealand child and adolescent road accident survivors. In 2000, 1216 under-15 year-olds were injured on New Zealand roads. A national sample of 19 young people (8-17 year-olds) and their parents completed a variety of assessment measures, including a structured clinical interview in 16 cases. Of the 16 interviewed child/adolescent survivors, 19% were diagnosed with PTSD, and 69% exhibited some significant, enduring psychological distress following their accident. Implications for mental health, educational attainment, family adjustment, and personal wellbeing are discussed. Part three considered the need for secondary prevention for young road accident victims, including as a priority, means for the identification and recognition of young, road accident survivors who are at risk of developing psychopathology following a road accident. To this end, a draft of a screening guide to enable teachers and medical practitioners to identify these young at risk, road accident victims was developed.

This research aims to develop an innovative framework to evaluate the social and environmental impacts of road maintenance activities and integrate these impacts to enable sustainable road maintenance decision making in Australia. The usefulness of the framework, including the indicators, their calculations and potential implementations, is also presented, using real life scenarios. The road agencies can usefully adopt the results of this study for developing sustainable maintenance activities, such as selecting truly sustainable maintenance activities.

Cette thèse souhaite contribuer au renouvellement des approches consacrées à la route en sciences sociales. Considérant la relation réseaux-territoires au prisme de la géographie culturelle, elle ambitionne de montrer que la route ne constitue pas seulement un support de déplacement, mais est dotée de significations pour ses usagers et les territoires traversés. L’hypothèse est que la route constitue une dimension de la territorialité, et conduit à la construction d’une « territorialité mobile », qui appréhende la mobilité comme un facteur de constitution des territoires et des territorialités. La thèse considère le cas des routes nationales françaises, qui ont longtemps compté parmi les principaux axes de communication du pays, et qui depuis les années 1990, font l’objet d’un intérêt patrimonial. Ces routes ne sont alors plus appréhendées uniquement dans leurs dimensions fonctionnelles, mais aussi dans leurs dimensions symboliques. La recherche a porté sur la route nationale 7 (RN7), qui sur 996 kilomètres, relie Paris à Menton (Alpes-Maritimes). Ces rapports territorialités/mobilités sont étudiés dans l’action collective d’acteurs territoriaux pour une part, et dans les pratiques individuelles d’usagers de la route d’autre part. L’entrée par la patrimonialisation permet d’opérer une démarche multiscalaire, en réfléchissant successivement à la construction de la RN7 comme un objet patrimonial, aux formes de mobilisation collective de l’objet route, dans ses acteurs (associations, musées et collectivités locales), ses valeurs et ses objectifs territoriaux, puis à l’appropriation opérée par les usagers. L’emploi de méthodes d’enquête qualitatives conduit d’abord à observer que la construction patrimoniale de la RN7 s’appuie sur des critères de différente nature, à la fois sociétaux, historiques et géographiques. Ces critères sont ensuite réinterprétés et réappropriés par les territoires à travers les actions patrimoniales mises en place. L’appréhension de la RN7 comme un objet patrimonial et sa mobilisation comme un outil de promotion des territoires conduisent à des formes de relation consubstantielles entre la RN7 et les territoires. Enfin, l’analyse du vécu de la RN7 chez des riverains, chauffeurs-routiers et touristes montre que la route constitue une dimension de leur territorialité, qu’elle soit appropriée dans ses dimensions patrimoniales ou fonctionnelles, et que sa pratique relève généralement d’un choix et de stratégies personnelles. Cette thèse permet ainsi de caractériser la place de la route dans la construction d’une « territorialité mobile », en soulignant, d’une part, la signification qu’elle peut donner aux territoires, et, d’autre part, le lien indissociable qu’elle entretient avec les territoires pour acquérir elle-même une signification
This thesis aims to contribute to the renewal of approaches to the road in the social sciences. Considering the relationship between networks and territories through the prism of cultural geography, it aims to show that the road is not only a means of travel, but is also endowed with meanings for its users and the territories it crosses. The hypothesis is that the road constitutes a dimension of territoriality, and leads to the construction of a "mobile territoriality", which apprehends mobility as a factor in the constitution of territories and territorialities. The thesis considers the case of the French national roads, which have long been among the country's main communication axes, and which since the 1990s have been the subject of heritage interest. These roads are no longer considered only in their functional dimensions, but also in their symbolic dimensions. The research focused on the national road 7 (RN7), which over 996 kilometres links Paris to Menton (Alpes-Maritimes). These territoriality/mobility relationships are studied in the collective action of territorial actors on the one hand, and in the individual practices of road users on the other. Entering through heritage enables a multiscalar approach to be taken, by considering successively the construction of the RN7 as a heritage object, the forms of collective mobilisation of the road object, its actors (associations, museums and local authorities), its values and its territorial objectives, and then the appropriation made by users. The use of qualitative survey methods leads first of all to the observation that the construction of heritage on the NR7 is based on criteria of different natures, at once societal, historical and geographical. These criteria are then reinterpreted and reappropriated by the territories through the heritage actions put in place. The understanding of NR7 as a heritage object and its mobilisation as a tool for promoting territories leads to consubstantial forms of relationship between NR7 and territories. Finally, an analysis of the experience of the NR7 among local residents, road drivers and tourists shows that the road is a dimension of their territoriality, whether it is appropriate in its heritage or functional dimensions, and that its practice is generally a matter of personal choice and strategies. This thesis thus makes it possible to characterize the place of the road in the construction of a "mobile territoriality", by underlining, on the one hand, the meaning it can give to territories, and, on the other hand, the inseparable link it maintains with territories in order to acquire meaning itself