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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Queue methods for variability in congested traffic

Taylor, N. January 2014 (has links)
Time-dependent queue methods are extended to calculate variances of stochastic queues along with their means, and thereby provide a tool for evaluation and better understanding of travel time variability and reliability in congested traffic networks and other systems, including through probability distributions estimated from moments. Objectives include developing computationally efficient analytical methods, and achieving robustness by reflecting the underlying structure of queuing systems rather than relying on statistical fitting, New deterministic and equilibrium formulae for queue variance are developed, acting also as constraints on estimating time-dependent queues generated by a range of processes, enabling improved accuracy and reliability estimates. New methods for approximating equilibrium and dynamic probability distributions use respectively doubly-nested geometric distributions and exponentially-weighted combinations of exponential and Normal functions, avoiding the need to rely on empirical functions, costly simulation, or equilibrium distributions inappropriate in dynamic cases. For growing queues, corrections are made to the popular sheared approximation, that combines deterministic and Pollaczek-Khinchin equilibrium mean formulae in one time-dependent function. For decaying queues, a new exponential approximation is found to give better results, possibly through avoiding implicit quasi-static assumption in shearing. Predictions for M/M/1 (yield) and M/D/1 (signal) processes applied to 34 oversaturated peaks show good agreement when tested against Markov simulations based on recurrence relations. Looking to widen the range of queues amenable to time-dependent methods, dependence of stochastic signal queues on green period capacity is confirmed by an extended M/D/1 process, for which new formulae for equilibrium moments are obtained and compared with earlier approximations. A simple formulation of queuing on multiple lanes with shared service is developed, two-lane examples with turning movements showing fair match to simulation. The main new methods are implemented in a spreadsheet demonstrator program, incorporating a database of time-sliced peak cases together with a procedure for estimating dynamic probability distributions from moments.
2

Psychological correlates of road crash types

Meadows, M. L. January 1994 (has links)
The research reported in this thesis examines possible psychological correlates of road crash involvement, both that of car drivers in general and that of young drivers in particular. In Chapter One the importance of the prevention of road crashes is discussed. A brief review of the study of driver behaviour summarizes the range of previous research in this area. Various methods of studying driver behaviour are critically discussed. In Chapter Two the over-representation of young drivers in the crash statistics is examined. This chapter provides an overview of previous research into the correlates of young driver crashes. It is suggested that a previously overlooked, possible contributor to road crashes may be the influence of 'extra motives' on driving behaviour. Extra motives are defined as motives of the road user which do not involve the 'official' goals of safety and mobility on the road. Certain extra motives may be particularly salient to young drivers. Chapter Three reports Study One in which a measure of two extra motives was developed in the form of a Driving Motivation Questionnaire (D.M.Q.). This consisted of 50 items derived from Bliersbach and Dellen's (1978, 1980) description of five driving patterns. Bliersbach and Dellen's findings were not replicated. Two factors, driving for thrill and competitive driving, were established through factor analysis. In Chapters Six and Seven a second study is described. For Study Two a second questionnaire was produced to examine the relationship of the extra motives embodied in the D.M.Q. with self-reported commission of driving violations, errors and lapses in the form of the Driving Behaviour Questionnaire (D.B.Q.) (Reason, Manstead, Stradling, Baxter and Campbell, 1990; Reason, Manstead, Stradling, Parker and Baxter, 1991). Development and prior use of the D. B. Q. is di scussed in Chapter Four. The relationship of the D.M.Q. and the D.B.Q. to self-reported, overall crash frequency and to specific types of crashes was studied using a crash typology developed by West (1994). Development and previous use of the crash typology is discussed in Chapter Five. In Chapter Eight the results of the second study are discussed with particular reference to the following issues: 1. The replication of the three factor structure of the D.B.Q. The significant, independent prediction of specific types of crashes by the D.B.Q. factors. 2.The replication of the D.M.Q. Thrill factor obtained in Study One. The significant, independent prediction of specific types of crashes by the Thrill factor. 3.The failure to replicate the D.M.Q. Competition factor obtained in Study One. The attainment of a D.M.Q. Sedate driving factor. 4.The reliability and usefulness of West's classification scheme. 5. The association of varying driver characteristics with distinct crash types, particularly the roles of inexperience and age in young driver crashes. 6. The suggestion that; Driver errors may only have serious consequences when the driver making the error or a nearby driver is violating or thrill seeking; Thrill seeking may only lead to crashes when the driver seeking thrill or another nearby road user makes an error; Violations, on the other hand, may cause crashes no matter how skilful the driver or those drivers nearby.
3

A statistical analysis of road traffic accidents and casualties in Bangladesh

Sheikh, Mohammad Mizanur Rahman January 2009 (has links)
A statistical analysis was conducted for road traffic accidents and associated casualties in Bangladesh. This was undertaken in order to assist the policymakers to take appropriate steps to be reduced the road traffic accidents and the associated casualties. Secondary data (collecting from Bangladesh government publications) were explored, analysed and modelled statistically. An exploration was undertaken using the averages (per annum) of rates of KSI/ fatal casualty, accident and involved vehicles applying Bar-charts. In addition, annual time series data were investigated using trend lines. A detailed analysis of variances was conducted using the rates (per 10,000 populations) of BRTA traffic accident and casualty data applying mainly non-parametric tests. Time series; one-way and two /three-way classified data are analysed applying linear regression model; Mann-Whitney or Kruskal-Wallis tests and Univariate regression model respectively. Finally, modelling of two/ three-way data was conducted using the frequencies of fatal casualty, fatal accident and involved vehicles applying Poisson regression. The most significant findings from this research were that pedestrians are highly involved in the casualty figures. Fatal hit pedestrian is the main collision type accident. Maximum fatal accidents occur at out of junction. Cities have higher accident and casualty rates than that for non-cities (divisions/ districts, excluding cities). In particular, Rajshahi city and Dhaka city have the highest accident rates. National highways are the main venues of accidents and casualties. Heavy vehicles including buses and trucks are predominantly involved in casualty accident. Implications from this research have been considered and suitable recommendations have been made.
4

An examination of the characteristics of young drivers in Northern Ireland and their involvement in road traffic collisions

Redpath, Gwyneth Margaret January 2016 (has links)
The aims and objectives of this thesis were to examine the reasons for the high proportion of collisions resulting in death or serious injuries, especially to young drivers on Northern Ireland roads by examining why they suffer more deaths and injuries than their proportion in the population. This was achieved by issuing and analysing a questionnaire based on one previously issued in GB; conducting a Naturalistic Driving experiment with a qualified, approved driving instructor and his pupils to study the use of an audible signal as a means of highlighting hazards; and desk research. Results showed that new drivers in Northern Ireland are not significantly different from those in GB and that an audible signal can be useful in slowing down drivers ahead of a hazard. It was concluded that traffic fatalities have reduced because of the depressed economy but are likely to rise as the economy improves and that the use of a pre-emptive/advanced warning or signal could be one means of enabling young driver road traffic fatalities to remain low, even as the economy improves and more younger drivers start driving on the roads.
5

Road traffic injury prevention in children in rural Bangladesh

Baset, M. U. January 2013 (has links)
Background: Childhood road traffic injuries (RTIs) are a major public health problem internationally; little research has been conducted on preventing childhood RTIs in Bangladesh. Aim and Objectives: Aim: to develop a pilot intervention to reduce childhood RTIs in rural Bangladesh. Objectives - to: • determine the epidemiology of and risk factors for childhood RTIs • explore community perceptions of childhood RTIs and their prevention • develop a pilot package of preventive interventions and evaluate the package to assess its feasibility and acceptability Methods: Five studies were conducted using mixed methods. Study A examined the epidemiology of childhood RTIs using three data sources. Study B explored community perceptions through focus groups. Study C (school survey) investigated exposure to the road environment. A pilot intervention developed and implemented (study D), was evaluated for its feasibility and acceptability in rural communities (study E). Results: Studies A-C showed that RTIs are a growing problem, especially for rural child pedestrians. The rate of childhood RTIs mortality was three times higher in rural than urban areas (9.1 versus 2.7 per 100,000 children years). Pedestrians (42%) were the main victims in rural areas, with children aged 5-9 particularly vulnerable. Seven focus groups were conducted which provided insights into the causes of RTIs, e.g. Problems finding safe places to cross, poor supervision. The school survey showed that children lacked knowledge and skills about road crossing. Risk factors included gender, age, accompanying person, and travel mode. The “Safe Child Pedestrian” pilot programme was developed and implemented in six schools, 36 school children aged 7-9 years were trained at the roadside by volunteers. The programme was feasible and acceptable for rural communities. Conclusion: The expansion of Bangladesh’s rural road network continues, with child pedestrian injuries increasing. Practical child pedestrian training is an initial step in engaging communities to reduce RTIs. Achievement: This is the first attempt to explore the situation of childhood RTIs in rural Bangladesh and develop, implement and evaluate a programme for child pedestrians.
6

Statistical studies of road accidents and injury severity

Hutchinson, T. P. January 1976 (has links)
This thesis is concerned with the quantitative study of certain characteristics of road traffic accidents, with particular. attention being paid to the severity of injury sustained by the victims thereof. The results fall into two main groups: those dealing with the frequency and severity of accidents to particular categories of road user, and those relating to a new theory of injury severity. The following is a list of the questions considered in the first of these groups: factors relating to the severity-of pedestrian injury (with special attention to design of vehicle), factors affecting the survival time of pedestrians killed in road accidents, relation of. model of car to degree of (a) leg, and (b) head injury of its driver, effect of vehicle, age and sex of driver, and locale. on (a) the relative numbers of single- and two-car accidents, and the, proportion of overturning in single-car accidents. Several sections of the thesis are devoted to developing appropriate. statistical: procedures for these analyses. The new theoretical framework for assessing-injury severity that is proposed in the penultimate chapter quantifies the correlation. between the proportion of casualties who are killed and the proportion who are seriously injured. Finally, this theory is used to. explain the positive correlation that is empirically. found to occur between the degrees of injury to the two drivers involved in two-vehicle accidents when only a narrow range of mass ratios. is considered.A table of the major results in this thesis, together with some lines for future research which they suggest, is given on pages 357-363.
7

Geographical information systems coupled prediction modelling of road traffic accidents in Brunei

Ladi, Hj Supry Hj Ag January 2006 (has links)
The analysis of road accident data has led to the development of a number of prediction models to allow testing of road improvement schemes. However, the advances in Information Technology and particularly within the field of Geographical Information Systems (GIS) has enabled it to be linked with applied sciences such as Fluid Mechanics, Highway Design and Traffic Engineering to create a "loosely" to "tightly coupled" GISbased system. Such a system allows correction and simulation tasks to be performed whenever necessary. This approach has been applied to the problem in Brunei where they are at the initial stage towards realising the importance of road-safety research. This work has been proved to contribute tangible benefits for the Brunei road safety authorities. ArcGIS software was used to produce clusters of road accidents along a road and create a road accident database linked with the Brunei road network which form the initial stage of this research. The research develops a new 'Modified Voronoi Process' (MVP) for the identification of accident hotspots along a road. This technique uses a combination of GIS functionalities with Microsoft Excel software. The establishment of a Hotspot Zone dimension (HZD) within the MVP is creative and is very beneficial for Brunei road safety authorities and other researchers. The technique incorporates Brunei road accident hotspot definition established by the author. The final outcome of this research is the development of a GIS-based Road Accident Prediction System and is an innovation and enhancement to the world of road accident prediction system and particularly in Brunei. The system incorporates an external prediction model, which is "tightly coupled" or integrated with a GIS. The coupling enables the prediction to be carried out on a single platform for easy input and computation. The system was tested using accident data acquired from manually recorded 24-hour police reports and statistical software used to analyse the sensitivity of accident locations. The system was also used for a sensitivity analysis of the application of the United States Federal Highway Agency (USFHA) prediction model on a segment of road in Brunei.
8

Drug control policy in Thailand : the shift more towards harm reduction

Waeladee, Sritakool January 2014 (has links)
Previous research has demonstrated that a long development of Thai drug policy along with crime control and immorality explained the dominance of a prohibition ideology in drug policy in the present day. None of the previous research has yet to address the significant change occurring recently with the adoption of harm reduction ideas to the Thai drug policy, 20 10/20 II. Hence, this research aims to be the first to provide novel insights into such important incident. This research has two key aims. The primary research aim is to gain better understand of the process of 'how' factors, such as, actors, policy ideas, networks, institutions and socio-economic forces interacted and possibly contributed to the recent change and 'why' under which conditions, despite entrenched prohibition ideology, the recent change of the drug policy still occurred. The secondary research aim is to test the applicability of the dominant US-based theories, particularly, the Policy Advocacy Coalition Framework (ACF) and the Punctuated Equilibrium Framework (PEF) to explain the recent change. Aligned with the pragmatists' worldview, this research is designed in a case study tradition using mixed methods by which theories are, possibly, both inductively developed and deductively tested. While qualitative methods are primarily used to achieve the primary aim, the quantitative method of social network analysis is embedded to suppol1 a systematic test of key network relational assumptions. This research provides novel knowledge on the process of the recent change in which institutions played the key roles. Institutions shaped the roles of key actors' behaviour, their networks/collective actions in relation to harm reduction advocacy at subsystems. Conflicting institutional values explained the conditions of the subsystem
9

Human factors in air accident investigation : a training needs analysis

Burban, Camille January 2016 (has links)
Human Factors (HF) has long been identified as one of the main causes of incidents and accidents in the transportation industry, and more recently has become increasingly important in air accident investigation and safety improvement. As a result, many National Investigation Agencies (NIAs) are now explicitly acknowledging HF in their final investigation reports. Whereas engineering-and operations-led investigation can highlight what happened and how it occurred, it is increasingly recognised that the integration of HF into an investigation can help understand why a sequence of events led to an incident or accident. However, there are considerable challenges to more thorough integration of HF into air accident investigations. Most notably, there remains a reluctance amongst some NIAs to fully embrace HF and address potentially important HF issues in detail in their investigations. Consequently, there is a risk that some investigations are consistently overlooking potentially critical HF issues, and as a result fail to fully address why an incident or accident occurred. There is a need for research that examines these challenges, including the possible gap that exists between research and industry regarding the development and applicability of accident analysis tools, and that provides practical solutions to enable a better integration of HF in air accident investigations ... [cont.].
10

The impact of the school safety zone on passenger car equivalent values in Indonesian urban roads

Hidayati, Nurul January 2013 (has links)
In heterogeneous traffic analysis, traffic flow is measured by converting the values of different vehicle types using Passenger Car Equivalents (PCE) values. School Safety lone (ZOSS) facilities were provided by Indonesian Government to improve the safety of pedestrian by controlling the speed of vehicles near primary schools located around the main road. The effect of school locations around the main street is the presence of roadside activities such as pedestrians, private vehicles stopped, and bus stops. This condition will affect the traffic flow. The objectives of this research were to develop the model of PCE values for Indonesian urban roads equipped with ZOSS, and to determine how much the lOSS changes the PCE values. The surveys were conducted in 9 roads, in Surakarta, Sragen, and Y ogyakarta. Each road was divided into 4 loci corresponding to the locations of camcorder, i.e. Locus B (before), Locus l (at zebra crossing), Locus A (after) and Locus 0 (outsideZOSS area). Road segment was used to see the changes that might occur in 9 different locations, while locus was used on the same road but at certain point were equipped with a relevant facility of lOSS. This research has used the speed ratio method which expressed the ratio between the average speed of a vehicle type and the average speed of cars. This variable was combined with the percentage and a dimension ratio of each vehicle type, as well as with a measure of side friction. The recommended model was modified based on the Speed-Based Method referring to the Indonesian Highway Capacity Manual.

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