This thesis aims to apply recent conceptual frameworks for climate change impact assessment to the road freight sector of Great Britain in order to identify potential future safety issues. The freight sector is a key component of Great Britain’s economy, and one which is particularly vulnerable to the effects of adverse weather. An assessment of the current patterns in weather related freight accidents is produced, and existing studies on accident causation are elaborated upon to arrive at relationships between key meteorological parameters and freight accident rates. These relationships are extrapolated onto various climate scenarios under low, medium and high emissions for the 2020s, 2050s and 2080s using UKICP09 climate tools to arrive at projections of possible impacts at a regional scale. This thesis also addresses a key criticism of the previous climate change impact assessment literature; that studies usually neglect the consideration of what the network will look like in the future, how it will be used, and how this will impact upon its vulnerability to meteorology. The way in which the network is designed, the resilience of the vehicles that operate on it and the split of usage between the various modes will all affect the impacts that are likely to be seen, and are all determined by the broader socio-economic pathway of the country. Delphi techniques are used for short term forecasts of growth and to identify emerging issues with the industry. UKCIP data is used to extend these projections to 2050. By combining social and physical techniques, a more holistic picture of future impacts is found. Although the confluence of safer technology and a reduction of winter road icing and summer precipitation events could potentially lead to a safer operating environment, certain scenarios which promote high emissions, a larger freight fleet and low investment in infrastructure could cause problems, especially for winter precipitation events.

When project sites consist of substandard design elements according to standards set by the Federal Highway Administration (FHWA), design exceptions are implemented. The goal of this thesis is to analyze a sample set of 18 design exceptions taken from a total of 467 design exceptions approved in Georgia from 1995 – 2012. Crash data were obtained at the locations of each of these design exceptions three years before the let date and three years after the construction end date. To compensate for causal factors other than the design exception on the roadway, similar information from a range of control sites were also obtained. These control sites consisted of projects without design exceptions that occurred within the same time constraints as the design exception projects, were of the same work type, and were either located on the same route or within the same district. The potential safety impacts of the design exceptions were evaluated by comparing the before and after crash rates of projects before and after crash rates at these control sites Based on these data, no statistically significant relationship between the existence of a design exception and crash rates was identified. The sample set in this study was too small and the number of crashes found at both projects with design exceptions and control sites without design exceptions was too low to perform a significant Empirical Bayesian (EB) analysis. When additional data is available, an EB before and after analysis is recommended to compensate for any potential regression to the mean bias.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p.120-125 ). Also available in electronic format on the Internet.

This research seeks to investigate how additional data sources can be used within traffic control systems to reduce average delay and improve reliability of journey time. Current state of the art urban traffic control systems do not take full advantage of the improved granularity of data available as they use traditional, static detection methods such as inductive loops, infra-red and radar. Therefore further research was required to fully understand what new data sources are available, how they could be used and if there are any potential benefits for traffic control systems. The transport industry is moving into an era of data abundance as more people use smart phones, satellite navigation systems, Wi-Fi and Bluetooth devices. These richer data sources could provide additional information (vehicle location, speed and destination data) but it is currently unknown as to whether they can improve the performance of the road network. Much of the research in this thesis has been published through conference and journal papers. A novel traffic control algorithm called DEMA was developed during this research, which can significantly outperform MOVA (a leading industrial control algorithm) through reducing average delay by up to 34% when additional data sources are incorporated into the decision process. DEMA uses vehicle location, speed and turning intention information to select the most suitable stage for minimising delay. Also a study was conducted to determine if turning intention information could be predicted from outside of a vehicle, which is a previously un-researched area. The results demonstrated that people could correctly predict turning intention with a 70% median success rate when the vehicles were 50 metres from the junction. The outcomes of this research could have a significant impact on the future of urban traffic control systems as new data sources become more readily available in the transport industry.

There has been extensive research and development into the capacity of modern offside priority roundabouts since the 1970’s. Despite this, there remains a major gap in existing knowledge with regards to the factors and variables which affect roundabout entry capacity. This is reflected in the differences and inconsistencies in inputs and methodologies between existing state-of-the-art models. Evaluations with recent data collected from 35 roundabout entry lanes in the field have shown that this limits the accuracy of state-of-the-art models, particularly in their ability to explain site-to-site variation in entry capacities. New empirical models have thus been developed for lane capacity using regression, and benchmarking against neural networks showed that they performed well with the shortlisted explanatory variables. These regression models were based on exponential-in-Qc and linear-in-Qc forms, and outperformed existing state-of-theart models. In the new models, entry-exit separation distance and exiting flows on the same arm were found to be more useful predictor variables (when used in conjunction with other variables) compared to others used in more-established models (e.g. entry radius and entry angle). To investigate the effects of separation distance and exiting flows through microscopic simulation, stochasticity in separation distances was modelled through a novel approach in Vissim involving multiple exit connectors. This was significant as the variability of separation distances had not been explored before, whether through analytical or simulation approaches. The separation distance was found to have a piecewise linear relationship with capacity, while exiting flows had a linear positive relationship which becomes negative as the inhibitory effect increased at low separation distances. The two main mechanisms explaining these effects of exiting flows were the inhibitory mechanism (caused by drivers unable to distinguish between circulating and exiting vehicles), and changes in circulating headways. A revised empirical model incorporating this piecewise relationship performed as well as the exponential-in- Qc and linear-in-Qc models, suggesting that the impacts of exiting flows were modelled reasonably well. By improving our understanding of the impacts of these two variables on capacity, this is an important step towards the improved modelling of roundabout entry capacity.

In recent decades the Public Private Partnership (PPP) has been widely regarded as an innovative way to construct transport infrastructures and to improve the quality of service. As the number of PPP cases has increased, many countries have tried to standardise PPP models to minimise the costs of trial and error. South Korea, where 426 PPP projects have been undertaken since 1994, usually preferred the BTO (Build-Transfer-Operate) model for transport. In the BTO model, the private sector recoups its investment by charging end users directly and hence should bear the traffic demand risk. However, the Korean Government shared the demand risk through a minimum revenue guarantee to induce private sector involvement, and this led to many criticisms of the BTO model. Tariffs in the BTO case were much higher than those of public operators, but the Government still had to pay large amounts of guaranteed revenue. Thus, BTL (Build-Transfer-Lease), where the demand risk is on the public sector, has become an alternative model. The BTL is the “service sold to the public sector” model which is similar to the DBFO (Design-Build-Finance-Operate) in the UK. This thesis examines which of the BTO and the BTL PPP models is optimal to save governmental expenditure for transport infrastructures such as road and rail. Appropriate traffic demand risk sharing, which a particularly controversial issue in South Korea, is explored. These research objectives are examined through five case studies: the Incheon Airport Expressway and the Oksan-Ochang Expressway cases for road PPP; the Incheon Airport Railway, the Daegok-Sosa Railway and the Seoul Metro 9 cases for rail PPP. Through a detailed literature review and five case studies, the thesis shows that the optimal PPP model, which is measured by the VFM (Value for Money) assessment, needs to satisfy the interests of public sector, private sector, and end users. Based on these assessments and including these three viewpoints, it is concluded that the optimal PPP model for road can be the BTL where the public sector can save expenditure or reduce the level of tariff. Traffic demand risk for roads is relatively low, so the public sector does not have to transfer it to the private sector with high profit rate. In the case of rail, the limited revenue and high cost make a project difficult to be financially free standing by the BTO model. However, the BTO can be a better option in urban rail if traffic demand risk is shared appropriately.

The potential for binder rich bituminous road surfaces to deliver low levels of dry friction was first noted in 1944. Using established test methods exploiting basic principles of physics first tested in criminal court in the 1940s (and still in use today) it has been possible to show statistically that modern negative textured road surfaces (NTS) deliver levels of dry friction significantly below those considered typical by collision investigators for the more traditional positive textured surfaces (PTS). NTS surfaces are shown to perform relatively worse in the absence of ABS (Anti-Blockier System, Anti-lock braking) than PTS equivalents such as Hot Rolled Asphalt (HRA). Skid tests undertaken on DRY NTS surfaces with ABS braking have been shown to manifest momentary low levels of deceleration similar to those experienced during NOABS tests on the same surfaces and to generate dash like skid marks atypical of ABS tests on DRY PTS surfaces. The ratio of peak to sliding friction also appears lower for dry NTS surfaces than for Dry PTS surfaces documented in the literature. Using high-speed video and false colour infrared imaging it has been possible to see the low friction phenomenon termed “bituplaning”. Vehicles equipped with ABS have also been shown to suffer momentary “bituplanes” resulting in less than optimum performance. Tyre deformation during dry skidding on NTS appears reduced in relation to a PTS equivalent.

In recent years, rapid changes in markets including outsourcing and globalisation of trade and production systems have led to a dramatic upsurge of interest in retail logistics with the aim to minimise operational and logistics costs, improve responsiveness and ameliorate customer services. The notable massification and commodification of production and consumption have created structural changes in traditional urban distribution systems with the establishment of peripheral transshipment and hub systems. In the light of sustainable development, green logistics and transparency on emissions have become a further requirement conforming to the times with a special focus being placed on the logistics of collecting, processing and recycling waste materials. This has increased the need to develop more efficient and effective city distribution plans and to establish optimised logistics models which will integrate the delivery of materials and the collection of waste and returns in order to reduce congestion, costs and emissions. To this end, this thesis aims to investigate opportunities to improve existing delivery mechanisms in a dedicated shopping centre in the UK in order to minimise freight activity and emissions, while optimising the reverse flow system for product returns and waste. Using a substantial database of logistics operations compiled for 92 businesses in Southampton’s shopping centre, the study aimed to understand the current opportunities to better utilise the existing back-load capacity and assess the potential logistical and environmental savings that could arise from the use of a peripheral consolidation centre for core goods and waste. Following statistical analysis on WestQuay managers, logistics providers, waste contractors and head offices responses it was found that the fill rates of delivery vehicles were considerably low and therefore there was a great potential to increase back-load rates and consolidation among loads of different businesses. In examining the waste and return flows it was found that there were already centrally managed collections of general waste and some recyclables and therefore further opportunities to reduce the logistics and environmental impact would lie into the consolidation of forward traffic and the back-loading of specific waste streams such as hazardous materials. The examination however of specific case study examples exhibited the variety in the characteristics and properties of hazardous wastes and the role of material-specific legislation on the way different waste streams should be managed and disposed of which limited the collaboration opportunities among businesses producing different waste streams. Instead the study highlighted the considerable transport, environmental and economic gains that could be achieved by individual businesses through the use of regional waste contractors and recycling sites. With regard to the consolidation of forward flows, the study reviewed a number of existing consolidation schemes and their characteristics to identify potential strengths, weaknesses and risks that would impact on the operation of a consolidation centre in the outskirts of Southampton. Various scenarios regarding the operation of the consolidation scheme were examined considering different take up combinations among different vehicle modes and loads. The scenario analysis suggested that the establishment of the consolidation centre could offer great opportunities to reduce the overall urban freight activity, while mitigating the environmental impacts and cutting down the total costs to businesses.

Walking is healthy, environmentally beneficial and sustainable to human society. Travellers increasingly are being encouraged to walk more. However, pedestrians’ interaction with motorised vehicles is a major constraint to their movement. Many innovative treatments have been developed to balance the two modes. Proper methods are required to evaluate and compare performances of different treatments to support decision making. Micro-simulation is a useful supplementary tool for such evaluation and comparison studies for its cost-effectiveness and non-intrusiveness. However, there is a significant gap between capabilities of existing simulation models and practical needs. New understandings of the Pedestrian-Vehicle Interaction (PVI) behaviour and corresponding micro-simulation models are required to conduct micro-simulation studies of the interaction process between the two modes to derive new knowledge of the mixed traffic. This dissertation presents the development and application of a micro-simulation model, PVISIM (Pedestrian-Vehicle Interaction SIMulation), to study PVI behaviour in a range of circumstances in an urban street environment. Key contributions relate to the collection of a substantial data base, development and validation of the model, an appreciation of the value of the approach and new understandings of PVI behaviour. A series of studies to measure behaviour based on the data collected in Beijing, China have been detailed. Intra vehicle and pedestrian behaviour models were developed and validated separately, incorporating the best available understandings from existing published studies and in accordance with the specific local data. The two modes were integrated by interpreting new findings from the study of microscopic interaction behaviour of the two modes. The complete model was validated against field data independent of those used in model development, covering a number of typical scenarios, including both unsignalised and signalised situations. The validated model was applied to study a typical unsignalised scenario by analysing system performances under different combinations of vehicular traffic and pedestrian crossing demand, in terms of efficiency, safety and environmental impact. Also, operations of different treatments including no-control, Zebra crossing, fixed-time signal crossing and Puffin crossing at two typical types of locations were compared. Interpretations and recommendations were given for each application. The results can be used to supplement existing guidelines for pedestrian related problems, and also contribute to the knowledge base to incorporate pedestrians into current micro-simulation tools in a more realistic way.

Due to urbanization, industrialization and population increase, a substantial increase occurred in the number of vehicles and hence large numbers of end-of-use tires are being disposed every year. The vast majority of these tires are stockpiled or used as a fuel for combustion which, in both cases, affects the environment detrimentally. The use of tire rubber in cement-stabilized aggregate mixtures (CSAMs) will ensure beneficial use of large quantities of these waste materials, saving natural resources and may enhance the properties of CSAMs especially these related to brittleness and sensitivity to fatigue failure. Research was undertaken to investigate, at macro and mesoscale levels, the effect of both rubber and degree of stabilization and their combination on the behaviour of CSAMs in terms of the most influential pavement design properties under different static and dynamic modes of loading. These properties are strength, stiffness and fatigue. A range of testing equipment, methodologies and tools was developed, suggested and implemented to perform this investigation. Further investigation was also conducted to provide better understanding of the damage and failure mechanism through quantitative studying of the fractured surface, internal structure and surface cracking patterns under different testing modes. The results of this study revealed that the addition of rubber has a negative effect on the compaction efficiency, compressive, flexural and tensile strengths while the stiffness, under different testing modes, was slightly reduced. In addition, a tougher mixture was produced after rubber-modification which means a change from a brittle to a more ductile behaviour. This behaviour was observed through different stiffness modulus evaluation methods. On the other hand, increase in cementation level has resulted in an increase in both strength and stiffness for both reference and rubberized mixtures. However, the decrease in the mixtures’ strength due to rubberization was more obvious in highly cemented mixtures than the lightly cemented ones. On the other hand, a greater decline in the mixtures’ stiffness, due to rubber incorporation, was observed at low cement contents. This behaviour is related to the void-like behaviour which depends, to large extent, on the relative stiffness between rubber and surrounding matrix. Quantification of the fractured surfaces and cracking pattern utilizing the photogrammatry and fractal dimension concepts, respectively, revealed that the addition of rubber resulted in rougher and more tortuous cracks and increases disperse-ability of these cracks. This means the rubber-modification changed the cracking pattern which implies better load transfer through the cracks and less risk of reflection cracking. The investigation of the internal structure, at mesoscale level, showed that the cracks were propagated through the rubber particles at all investigated cementation levels. This contributed to a lengthening of the crack path and to the delaying of crack propagation by absorbing and relieving the stresses at the crack tip, especially at the microcrack level. The latter mechanisms are behind toughness and fatigue improvement. Evaluation of rubber distribution revealed uniform distribution and this decrease as rubber content increases. The results also indicated an improvement in the fatigue life for all rubber replacement levels. This was valid at all cementation levels. In terms of modulus degradability, rubberization of the cemented mixture has only a slight effect on this property while larger permanent deformation was accumulated after rubber inclusion. It was observed that the poorly cemented mixtures showed greater stiffness modulus degradation. Pavement analysis and design study showed that the decrease in the mixtures’ strength overshadowed any improvement due to both mitigation of mixtures’ stiffnesses or fatigue life enhancement. However, this is not the case for poor rubber mixtures where this mixture showed better behaviour than the reference mixtures.