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Roadway surface friction along the West Virginia Division of Highways' roadway network is key to the safety of all traveling motorists. Being geographically located in the rugged Appalachian Mountains, the West Virginia Division of Highways' roadway network is flooded with innumerable geometric and design challenges, causing drivers to have to exercise the most care and attention when navigating the network. This dissertation introduces the concept of roadway surface friction management to this network. For decades, roadway surface friction has only been tested and checked on an as-needed basis at crash sites and intersections, in legal situations, and pavement acceptance on construction projects. It also seeks to use the acquired data through a case study to insure proper methodology of roadway surface friction management, to develop sample safety performance functions and best crash estimates, and to apply this decision-making data to provide assistance and guidance in the selection of projects in the West Virginia Highway Safety Improvement Program. This dissertation follows the manuscript format and is composed of three papers. The first chapter of the dissertation examines the usage of Method 3 of the AASHTO Guide for Pavement Friction and the modifications to this method to collect existing roadway surface friction data along the District Ten portion of the network. The second chapter of the dissertation discusses the development of sample safety performance functions to estimate the average number of crashes along each of the tested roadway categories: Interstate Routes, United States Routes, and West Virginia Routes. It also discussed the development of best crash estimates using the Empirical Bayes Method. This is essential to be able to forecast how crash counts should improve, given the application of various roadway improvements. The third and final chapter of the dissertation develops the case study based on the District Ten portion of the network and shows how to enhance project selection in the West Virginia Highway Safety Improvement Program. This is completed by applying the safety performance functions and best crash estimates from the second chapter to arrive at real friction numbers for the network and their project impacts. / Doctor of Philosophy / Roadway surface friction along the West Virginia Division of Highways' roadway network is key to the safety of all traveling motorists. Being geographically located in the rugged Appalachian Mountains, the West Virginia Division of Highways' roadway network is flooded with innumerable geometric and design challenges, causing drivers to have to exercise the most care and attention when navigating the network. This dissertation introduces the concept of roadway surface friction management to this network. For decades, roadway surface friction has only been tested and checked on an as-needed basis at crash sites and intersections, in legal situations, and pavement acceptance on construction projects. It also seeks to use the acquired data through a case study to insure proper methodology of roadway surface friction management, to develop sample safety performance functions and best crash estimates, and to apply this decision-making data to provide assistance and guidance in the selection of projects in the West Virginia Highway Safety Improvement Program. This dissertation follows the manuscript format and is composed of three papers. The first chapter of the dissertation examines the usage of Method 3 of the AASHTO Guide for Pavement Friction and the modifications to this method to collect existing roadway surface friction data along the District Ten portion of the network. The second chapter of the dissertation discusses the development of sample safety performance functions to estimate the average number of crashes along each of the tested roadway categories: Interstate Routes, United States Routes, and West Virginia Routes. It also discussed the development of best crash estimates using the Empirical Bayes Method. This is essential to be able to forecast how crash counts should improve, given the application of various roadway improvements. The third and final chapter of the dissertation develops the case study based on the District Ten portion of the network and shows how to enhance project selection in the West Virginia Highway Safety Improvement Program. This is completed by applying the safety performance functions and best crash estimates from the second chapter to arrive at real friction numbers for the network and their project impacts.

Skidding contributes to up to 35% of wet pavement accidents. Pavement surface friction therefore is an important component of highway safety. The skid resistance also varies seasonally and reduces over time due to surface polishing. These leave the pavement in a state of increased risk of skidding accidents. An adequate surface friction that accommodates the seasonal and long term variations is essential for safety over the pavement surface service life. The resistance to skidding, however, depends on surface microtexture and macrotexture. Alternatively, increased texture aimed at increased and durable surface friction may affect the noise generated on the road. In fact, traffic noise is a growing problem throughout the world. Noise barriers, traditionally used for noise reduction, are expensive and inefficient in some cases. As the pavement surface characteristics play a key role in noise generation and propagation, it provides a window for noise reduction by altering the pavement surface. The challenge, however, is to provide a smooth, quiet, long-lasting, and economic pavement with adequate and durable surface friction. This research has been directed to address this challenge and to provide a realistic guideline. The tire-pavement noise, sound absorption, and skid resistance performances of various flexible and rigid pavement surfaces have been examined using the field and laboratory test data. Models for the prediction of pavement skid resistance including the seasonal and long term variations have also been developed correlating the influencing factors. A value engineering approach has been proposed to accommodate the construction and maintenance costs, longevity, smoothness, safety and noise in the selection of pavement surfaces.

Skidding contributes to up to 35% of wet pavement accidents. Pavement surface friction therefore is an important component of highway safety. The skid resistance also varies seasonally and reduces over time due to surface polishing. These leave the pavement in a state of increased risk of skidding accidents. An adequate surface friction that accommodates the seasonal and long term variations is essential for safety over the pavement surface service life. The resistance to skidding, however, depends on surface microtexture and macrotexture. Alternatively, increased texture aimed at increased and durable surface friction may affect the noise generated on the road. In fact, traffic noise is a growing problem throughout the world. Noise barriers, traditionally used for noise reduction, are expensive and inefficient in some cases. As the pavement surface characteristics play a key role in noise generation and propagation, it provides a window for noise reduction by altering the pavement surface. The challenge, however, is to provide a smooth, quiet, long-lasting, and economic pavement with adequate and durable surface friction. This research has been directed to address this challenge and to provide a realistic guideline. The tire-pavement noise, sound absorption, and skid resistance performances of various flexible and rigid pavement surfaces have been examined using the field and laboratory test data. Models for the prediction of pavement skid resistance including the seasonal and long term variations have also been developed correlating the influencing factors. A value engineering approach has been proposed to accommodate the construction and maintenance costs, longevity, smoothness, safety and noise in the selection of pavement surfaces.

Draft tube is very important part of hydraulic turbines. Only optimum work together with turbine can bring highest performance of this machine set. Hence it is necessary to deal with character of flow in the draft tube for different operating conditions. Efficiency of the draft tube depends on many phenomena of flow. Observing these phenomena and finding their relation with energetic transformation in the draft tube is a suitable tool to judge quality of draft tube performance. Incorrect design of the draft tube can sometimes cause lower efficiency of whole machine set. The goal of this thesis is finding the main reasons causing draft tube efficiency drop for given operating conditions.