• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 106
  • 26
  • 21
  • 14
  • 11
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 425
  • 198
  • 187
  • 38
  • 38
  • 37
  • 25
  • 24
  • 23
  • 21
  • 21
  • 19
  • 18
  • 18
  • 18
  • 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.
41

Pedestrian right-of-way violations at signalised pedestrian crossings in Edinburgh

Alnaqbi, Khalfan Saeed January 2013 (has links)
The review of available literature related to pedestrian accidents indicates that the occurrence of pedestrian accidents is influenced by a diverse range of factors. However, few empirical studies have documented the effects of distance of pedestrian accidents from pedestrian crossing area or junction. The few studies which investigated the impact of the distance from the crossing line on pedestrian accidents, suggest that the longer the distance from road crossing facilities, the higher the likelihood of a pedestrian accident. With respect to the influence of the type of pedestrian crossing on the incidence of pedestrian accidents, a substantial body of literature has found that the types of pedestrian crossing indeed affect the frequency of pedestrian collisions. Additionally, all the available studies reviewed indicated the positive impact of signalised crossings on the reduction of pedestrian collision risk. Data from STATS19 show that pedestrian severity rates are higher over the pedestrian crossing points or within 50 meters of pedestrian crossing facilities than those away from it. This is contrary to the expectations that accidents should be least over these crossing facilities. This study investigates in more detail the factors that affect accident occurrence at signalised pedestrian junction and pelican or similar type of crossing facilities in the Scotland area. The main objective of this current research has been to investigate those factors most commonly associated with pedestrian injury severity at a pedestrian crossing or within 50m of one. Accident data of 14 years (from 1993 until 2006) in selected sites show that 942 pedestrian accidents occurred on or within 50m of a signalised pedestrian crossing area. Grid references of accident locations as well as locations of pedestrian crossings were obtained from the STATS 19 database and the local city council. The data was used to identify the locations of accidents relative to the location of pedestrian crossing facilities. In terms of severity of injuries models, results suggest that pedestrians from the older group received more severe injuries, compared with those from younger groups. Again, this finding underlines the importance of regulations and subsequent enforcement of traffic laws that protect and promote the safety of older pedestrians. The models also showed an association between the severity of injury and the type of pedestrian crossing. Since more KSI accidents have been associated with pelican crossings, there may be a need to undertake raising awareness and education for pedestrians to improve pedestrian safety. In terms of ROW models; it was shown that turning manoeuvres were more likely to violate pedestrian's ROW and result in accidents than other types of manoeuvres. Moreover, the model showed that heavy-goods vehicles and cars are associated with pedestrian's ROW, as compared to other types of vehicles. The various issues related to accidents resulting from pedestrian right-of-way can be effectively resolved by rationalisation of pedestrian crossing types; and provision of education with regards to the rules and responsibilities of both pedestrians and drivers at all available crossings. The models developed to profile pedestrian accidents in Edinburgh suggest that the highest number of pedestrian accidents occurred at pedestrian crossing lines; and that the number of pedestrian accidents decreased when moving away from pedestrian crossing lines or within 50 metres of pedestrian crossing lines. These have serious implications in terms of requiring improvements to pedestrian crossing facilities that can then ensure better pedestrian visibility and provide the public with more protection from moving vehicles. Moreover, another implication of this finding is that more regulatory instruments must be revalidated and further developed, since there are no laws to prevent pedestrians from crossing the road at certain points. The only laws being enforced in the UK are those relating to the prohibition of walking on motorways or slip roads but not regarding loitering on pedestrian crossings. Therefore, the guidelines specified in the Highway Code to deal with pedestrian behaviour while crossing the road have to be revisited and further developed. The results show that accidents rates decrease as distance increase from the pedestrian crossing facilities. The most risky locations are those at the pedestrian crossings or within 10 meters and the distance from 10 to 30 meters before the pedestrian crossing facilities. Analysis of pedestrian accidents rates and severities for each of pelican and signalised crossings were discussed. An investigation of right-of-way violations associated with pedestrian accidents at pedestrian crossing areas or within 50 metres of the same was carried out. Modelling accidents rates and severities at these pedestrian crossings is also presented in this thesis. Multinomial logit, ordinal and probit logit and binary logit modelling are used to analyse the results.
42

Investigation of driving cycles as tools to assess travel demand management in Edinburgh and Abu Dhabi

Al Zaidi, Ahmed January 2013 (has links)
Traffic congestion today is a major problem in almost all of the metropolitan areas of the world. An increasing level of congestion results in negative impacts on the urban environment. These include environmental pollution, energy problems and traffic accidents. The analysis of these problems and the predictions of the impacts of any transport policies that could be devised to deal with them are very critical to their success. Traffic problems are almost the same in most modern cities either in developed countries or less economically developed countries. The driving cycle for a vehicle is the representation of a speed–time sequenced profile, which is developed for a specific area or city. It is an important requirement in the evaluation of the driver's behaviour and the performance of vehicles for a number of applications, mainly in the area of environmental studies. For example, fuel consumption and emissions' predictions need information input on the characteristics of driving patterns of traffic. The applications of driving cycle analysis can be extended however, to many more other areas. The motivation for this research is to investigate the detailed impacts of travel demand management (TDM) measures, that are already in application. This is to improve the network performance, using driving cycle analysis. It is important to explicitly assess these measures using a micro-level detailed approach in order to comprehend overall results in terms of emissions and network performance. These understandings will benefit government agencies and policy makers in their planning and appraisals. It will also benefit public transport providers to improve their service in attracting and retaining their customers. The developments of the real world driving cycles in Edinburgh and Abu Dhabi have been presented in this research. The analysis of real world data, which has been obtained from monitoring traffic conditions in both cities using the GPS tracking of traffic, is presented. This data was collected from trips which have been carried out on a number of traffic corridors in both cities. The assessment of various parameters of traffic (i.e. speed, time percentage spent on acceleration, deceleration, idling, cruising and cycle duration) and their statistical validity, produced a real world driving cycle for the buses as well as the private cars. Two TDM measures have been considered; bus lanes and traffic calming measures. At each corridor, a handheld GPS device was used to record speed, acceleration, deceleration and distances driven. This data enabled the analysis of driving cycles for the buses and for the private cars. The driving cycle analysis and investigations have further been investigated using regression analysis techniques. The results suggest that the approach shows potential but further research is needed with more data available. The results suggest that the driving cycle analysis approach would be very useful to have a better understanding of driving behaviour and also the detailed impacts of the transport policies on traffic. In terms of bus lanes and traffic calming measures, the results show some positive impacts of these policies, while there are evidences of some negative impacts as well. These findings would be very valuable for the policy decision makers. It is recommended from this research that the driving cycle analysis could be utilised effectively in the assessment of TDM measures. Further investigations and analysis of driving cycle is urgently recommended in a number of research directions. Combined GIS and GPS data could also enhance the development in this research.
43

Pedestrian detection by computer vision

Reading, Ivan Alaric Derrick January 1999 (has links)
This document describes work aimed at determining whether the detection, by computer vision, of pedestrians waiting at signal-controlled road crossings could be made sufficiently reliable and affordable, using currently available technology, so as to be suitable for widespread use in traffic control systems. The work starts by examining the need for pedestrian detection in traffic control systems and then goes onto look at the specific problems of applying a vision system to the detection task. The most important distinctive features of the pedestrian detection task addressed in this work are: • The operating conditions are an outdoor environment with no constraints on factors such as variation in illumination, presence of shadows and the effects of adverse weather. • Pedestrians may be moving or static and are not limited to certain orientations or to movement in a single direction. • The number of pedestrians to be monitored is not restricted such that the vision system must cope with the monitoring of multiple targets concurrently. • The background scene is complex and so contains image features that tend to distract a vision system from the successful detection of pedestrians. • Pedestrian attire is unconstrained so detection must occur even when details of pedestrian shape are hidden by items such as coats and hats. • The camera's position is such that assumptions commonly used by vision systems to avoid the effects of occlusion, perspective and viewpoint variation are not valid. •The implementation cost of the system, in moderate volumes, must be realistic for widespread installation. A review of relevant prior art in computer vision with respect to the above demands is presented. Thereafter techniques developed by the author to overcome these difficulties are developed and evaluated over an extensive test set of image sequences representative of the range of conditions found in the real world. The work has resulted in the development of a vision system which has been shown to attain a useful level of performance under a wide range of environmental and transportation conditions. This was achieved, in real-time, using low-cost processing and sensor components so demonstrating the viability of developing the results of this work into a practical detector.
44

The effect of police enforcement on road traffic accidents

Scott, Andrew January 2010 (has links)
The primary goal of this thesis is to investigate the effectiveness of police enforcement on Road Traffic Accidents; specifically, ‘Does police enforcement activity have any real effect on levels of Killed and Seriously Injured road traffic accidents?' Data relating to forty one Police Force Areas in England and Wales was analysed by means of Zero Truncated Poisson regression, Cluster Analysis and Multilevel Modelling. Enforcement measures available to the police, for which data is available in this report, range from Prosecutions and Fixed Penalty Notices to Written Warnings and Vehicle Defect Rectification Notices. Results from the Zero Truncated Poisson regression models have significant effects (P < .05), in relation to both contemporary and lagged Annual data and contemporary Quarterly data, for all proxy variables except Prosecutions. Significant effects (P < .05) are also found for Fixed Penalty Notices lagged by two quarters, Vehicle Defect Rectification Notices and speeding related Fixed Penalty Notices lagged by one quarter. Results from Cluster Analysis verify the trend linking increased police enforcement with decreasing KSI rates. Clusters derived from population based KSI rates are more clearly defined than those using Vehicle kilometres travelled based KSI rates. Multilevel modelling found significant fixed effects (P < .05) for Fixed Penalty Notices and speeding related Fixed Penalty Notices in relation to both derived and regional clusters, linking an increase in enforcement to a decrease in the overall KSI rate. There would seem to be little doubt, based on the findings of this report, that higher levels of police enforcement, as measured here, lead to decreasing numbers of KSI accidents.
45

A case study analysis of the role of intermodal transport in port regionalisation

Monios, Jason January 2013 (has links)
This thesis presents an analysis of the role of intermodal transport in Notteboom and Rodrigue's (2005) port regionalisation concept, an approach to port development that focuses on the inland aspects of the process, as well as taking port development models from a spatial focus to a focus on institutions. It is argued that the port regionalisation concept is insufficiently disaggregated; it does not identify or classify different processes within the concept, nor does it explain how they operate or who drives them. In this thesis, the port regionalisation concept is broken down into its three constituent parts: inland terminals, market and logistics and the resolution of collective action problems. Each of these is examined in its own chapter, based on a case study methodology. The methodology was chosen for its ability to provide rich detail and build or extend theory, as the overall aim of this thesis is to critique the port regionalisation concept and extend its explanatory power. Part one follows a multiplecase design, analysing numerous European inland terminal developments in order to improve inland terminal classifications that can then contribute to the port regionalisation concept. Parts two and three each utilise a single case design, taking a single case in depth in order to explore in rich detail how these issues play out in industry. Part two studies the role of large retailers as the primary drivers of intermodal transport in the UK, while part three examines the development of an intermodal corridor in the United States, offering the opportunity to study a collective action problem in detail Part one reveals that port actors, both port authorities and port terminal operators, can be directly involved in the development of inland terminals, and that differences can be observed between terminals developed by port actors and those developed by inland actors. A conceptual distinction is proposed to capture this observation. Part two identifies barriers to port regionalisation, such as operational issues, spatial development decisions and a lack of integration between inland market players. Part three demonstrates the difficulties faced by public bodies attempting to direct regionalisation strategies, constrained by legitimacy and agency conflicts and an institutional structure that limits their effectiveness. An added contribution to the literature is the theoretical framework that is developed for the analysis of the institutional factors at play in resolving a collective action problem. While additional cases are required to advance the concept further, the cases in this thesis elucidate reasons why ports may not be controlling or capturing hinterlands through the strategies of integration that the port regionalisation concept suggests. It may be more accurate to state that regionalisation can only occur as long as a set of favourable commercial and institutional conditions are maintained. The findings from the cases presented in this thesis suggest that it is not easy to maintain such conditions, implying that regionalisation may be the exception rather than the norm.
46

Probit based methods in traffic assignment and discrete choice modelling

Rosa, Andrea January 2003 (has links)
No description available.
47

Strategic management in the global container shipping industry

Baird, Alfred January 2000 (has links)
Container shipping is of immense importance to global industry, and one of the critical enablers of globalisation. Analysis of the global container shipping industry suggests the potential for significant economies of scope and scale, and hence low costs and high efficiency, both recognised benefits of a global strategy. However, the global activities of container shipping lines are subject to a series of countervailing pressures, in particular, state regulation, shipper power, and the constant threat of competition. In an industry where differentiation has been absent, or at best difficult to achieve, there exists a growing belief amongst industry leaders that competitive advantage can be secured through providing a higher level intermodal service with a global network. This project identifies these and other important strategic management issuesr elating to containers hipping. it comparess trategiesa doptedb y industry leaders Sea-Land Service Inc. and Evergreen Line, two firms appearing to exhibit different modes of operation. Key differences in the strategies adopted by these lines' are identified. Through application of an established theoretical framework to help finther analyset he strategieso f thesec ompetitors,a nd aided by in-depth interviews with executives from each firm, it has been possible to identify specific organisational pressures associated with the conflicting needs for global operationali ntegration of activities and for local responsivenessT. he study has found that, in the global container shipping industry, competitors must implement strategies that facilitate a capability for both global integration and for local responsivenessT. his means that firms participating in the global container shipping industry must be multifocal; they must seek to develop the capability to manage both sets of demands simultaneously. Nevertheless, it is evident that whilst eachf irm is subjectt o broadly similar pressuresin respecto f the needs for integration and responsiveness, they adopt rather different strategies in attempting to meet these needs. With Sea-Land there is clearly an intermodal orientation, with more emphasis placed on intermodal capabilities and landside activities than on maritime aspects. Conversely, Evergreen Line was found to have a predominantly maritime orientation, placing greater emphasis on ships and containers and rather less emphasis on landside activities. These and other differences between carrier strategies relate to the series of strategic choices global liner shipping companies must make regarding the specific assets and operations necessary to provide a global container service. Using the grounded theory approach, a theoretical framework specific to the global container shipping industry has been developed that outlines these choices, illustrating the various options open to industry competitors. Entitled Strategic Choice in Container Shipping, the framework can be used as a teaching instrument to help explain industry complexity, and as an analytical tool to aid management decision-making and strategic planning.
48

The Belfast city region : travel behaviour, its impact on sustainability arising from the suburbanisation of dormitory settlements

Donegan, Karen S. January 2003 (has links)
No description available.
49

An analysis of motorcyclist injury severity by various crash configurations at T-junctions in the United Kingdom

Pai, Chih-Wei January 2008 (has links)
Motorcyclists that have no protective structures while motorcycling as other occupants of automobiles do can be particularly vulnerable to accident injuries (i.e., motorcycles are not as crashworthy as automobiles). Motorcyclists' susceptibility to accident injuries in nature may act synergistically with the complexity of conflicting manoeuvres between motorcycles and other motor vehicles to increase their injury severities in accidents that take place at junctions (e.g., T-junction or crossroad). Previous studies have applied crash prediction models to investigate influential factors on the occurrences of different crash configurations among automobiles but statistical models of motorcyclist injury severity resulting from different motorcycle-car crash configurations have rarely been developed. This current research attempts to develop the appropriate statistical models of motorcyclist injury severity by various crash configurations conditioned on crash occurrence at T-junctions in the UK. T-junctions are selected in this study because such junctions represent the single greatest danger to motorcyclists - for junction-type accidents, the statistics from the UK Stats19 accident injury database over the years 1991 and 2004 suggested that T-junctions were ranked the highest in terms of injury severity (Le., accidents at T-junctions resulted in approximately 65% of all casualties that sustained fatal or serious injuries) and accident occurrence (i.e., accidents at Tjunctions accounted for 62% of all motorcyclist casualties). This may be in part because there is a comparatively large number ofT-junctions in the UK. Although the author was unable to take into account the exposure factor due to the lack of such data (Le., the total number of T-junctions, and the number of motorcycles travelling on these locations), it remains true that more severe accidents happen at T-junctions than any other type of junction. In this present study, motorcycle-car accidents at Tjunctions were classified into several crash configurations based on two methods that have been widely used in literature. The first method is based on the conflicts that arise from the pre-crash manoeuvres of the motorcycle and car. The second method is on the basis of first points of impact of the motorcycle and car. The crash configurations that are classified in this current study based on the mixture of these two methods include (a) accidents involving gap acceptance (i.e., approach-turn crash and angle crash), (b) head-on crash, and (c) same-direction crash (i.e., sideswipe crash and rear-end crash). Since injury severity levels in traffic accidents are typically progressive (ranging from no injury to fatal/death), the ordered response models have come into fairly wide use as a framework for analysing such responses. Using the accident data extracted from the Stats19 accident injury database over 14-year period (1991~2004), the ordered probit (OP) model of motorcyclist injury severity were estimated because the dependent variable (i.e., no injury, slight injury, KSI: killed or seriously injured) is intrinsically discrete and ordinal. A set of the independent variables were included as the predictor variables, including rider/motorist attributes, vehicle factors, weather/temporal factors, roadway/geometric characteristics, and crash factors. The current research firstly estimated the aggregate OP model of motorcyclist injury severity by motorcycle-car accidents in whole. Additional disaggregate models of motorcyclist injury severity by various crash configurations were subsequently conducted. It appears in this current research that while the aggregate model by motorcycle-car accidents in whole is useful to uncover a general overview of the factors that were associated with the increased motorcyclist injury severity, the dis aggregate models by various crash configurations provide valuable insights (that may not be uncovered by an aggregate crash model) that motorcyclist injury severity in different crash configurations are associated with different pre-crash conditions. For example, the preliminary analysis by conducting descriptive analysis reveals that the deadliest crash manner in approach-turn crashes and angle crashes was a collision in which a right-turn car collided with an approaching motorcycle. Such crash patterns that occurred at stop-/give-way controlled junctions appear to exacerbate motorcyclist injury severity. The disaggregate models by the deadliest crash manners in approachturn crashes and angle crashes suggest that injuries tended to be more severe in crashes where a right-turn motorist was identified to fail to yield to an approaching motorcyclist. Other disaggregate crash models also identified important determinants of motorcyclist injury severity. For instance, the estimation results of the head-on crash model reveal that motorcyclists were more injurious in collisions where curves were present for cars than where the bend was absent. Another noteworthy result is that a traversing motorcycle colliding with a travelling-straight car predisposed motorcyclists to a greater risk of KSIs. These findings were clearly obscured by the estimation of the aggregate model by accidents in whole. In the course of the investigation of the factors that affect motorcyclist injury severity, it became clear that another problem, that of a right-turn motorist's failure to yield to motorcyclists (for the deadliest crash patterns in both approach-turn crash and angle crash), needs to be further examined. The logistic models are estimated to evaluate the likelihood of motorist's right-of-way violation over non right-of-way violation as a function of human attributes, weather/temporal factors, roadway/geometric factors, vehicle characteristics, and crash factors. The logistic models uncover the factors determining the likelihood of motorists' failure to yield. Noteworthy findings include, for instance, teenaged motorists, elderly motorists, male motorists, and professional motorists (Le., those driving heavy goods vehicles and buses/coaches) were more likely to infringe upon motorcycle's right-of-way. In addition, violation cases appeared to be more likely to occur on non built-up roadways, and during evening/midnight/early morning hours This present research has attempted to fill the research gaps that crash prediction models focused on analysing motorcyclist injury severity in different crash configurations have rarely been developed. The results obtained in this current research, by exploring a broad range of variables including attributes of riders and motorists, roadway/geometric characteristics, weather/temporal factors, and vehicle characteristics, provide valuable insights into the underlying relationship between risk factors and motorcycle injury severity both at an aggregate level and at a disaggregate level. This research finally discusses the implications of the findings and offers a guideline for future research.
50

An analysis of the challenges and opportunities facing the Hong Kong logistics industry

Lau, Anthony Siu Wing January 2010 (has links)
Hong Kong freight forwarding services have flourished along with China's economic development. Manufacturing activities in the Pearl River Delta (PRD) have provided the Hong Kong logistics sector with many business opportunities. However, due to the changes in the business environment, the industry is facing many challenges: competition from other local logistics companies in China, a shrinking market share on the shipping side, and increasing operating costs. The study aims to answer two questions: will the PRD continue to serve as the manufacturing powerhouse of the world and will exporters in the PRD continue to use Hong Kong:5 airport and port? The findings of this research will help academia and practitioners better understand the opportunities and challenges facing the Hong Kong logistics industry. This research was carried out in two phases. First, the author conducted exploratory interviews with manufacturers, logistics service providers, and government officials. Second, two questionnaires (one for manufacturers and one for logistics service providers) were designed based on the interviews and the literature review. The results of this two-stage analysis indicate that manufacturing in the PRD will continue to demand forwarding logistics support from Hong Kong because the latter continues to offer competitive advantage in several aspects compared with competitors in China. The Hong Kong government's pro-business attitude has helped to maintain Hong Kong's competitive advantage as a logistics hub; thus, the integration of Hong Kong and PRD logistics service providers has further enhanced this advantage in the PRD. Finally, based on these findings, a number of recommendations are offered. The empirical part of the research was completed before the onset of the 2008/9 recession; hence, no reference to its effect has been included in this thesis. The work also excludes any specific reference to the issues of carbon footprints and related environmental concerns because these are not primary issues for the industry as seen by the governments of the PRD region.

Page generated in 0.02 seconds