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Electronic Theses and Dissertations

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Articles 391 - 420 of 668

Full-Text Articles in Civil and Environmental Engineering

Nanoenhanced Polyurea As A Blast Resistant Coating For Concrete Masonry Walls, Heather Kathryn Daniell Rivera Jan 2013

Nanoenhanced Polyurea As A Blast Resistant Coating For Concrete Masonry Walls, Heather Kathryn Daniell Rivera

Electronic Theses and Dissertations

Blast impact is a major concern in the world today. The leading cause of death due to blast impacts is rapidly moving debris. To prevent this many researchers are looking for methods of improved blast resistance for concrete masonry walls. However, many available protective coatings are not flame retardant. This thesis focuses on nanoenhanced polyurea for applications in improving blast resistance, while possessing improved flame retardancy, of concrete masonry walls. The polyurea that is being researched is enhanced with nanoadditives in an effort improve both blast and fire resistance. These materials are dynamically tested and those showing marked improvement are …

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Mechanical Properties Of Portland Cement And Its Constituents At The Nano-Level, Brent French Jan 2013

Mechanical Properties Of Portland Cement And Its Constituents At The Nano-Level, Brent French

Electronic Theses and Dissertations

The following is a summary of research for a portion of the project titled Nano to Continuum Multi-Scale Modeling Techniques and Analysis For Cementitious Materials Under Dynamic Loading in association with North Carolina Agricultural & Technical State University and the US Army. This research investigates several attempts at creating a better Portland cement model at the atomistic level through molecular dynamics simulations. These models are modified to simulate damage to the basic cement structure, and are simulated using several combinations of forcefields and molecular dynamics tools. Experimental techniques such as nanoindentation, atomic force microscopy, and x-ray diffraction are applied to …

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3-D Numerical Simulation Of Dam-Break Flows Over Movable Beds, Reza Marsooli Jan 2013

3-D Numerical Simulation Of Dam-Break Flows Over Movable Beds, Reza Marsooli

Electronic Theses and Dissertations

Irvin Cooper was a prominent music educator in boys’ adolescent voice change research. Dr. Cooper developed the Cambiata concept as a method for teaching boys to sing throughout the voice change. This method was starkly different from the traditional model that encouraged the changing voice to be rested during the voice change. While working as the music supervisor for the Montreal protestant school system, Cooper developed his method of having boys sing during the voice change, which included arrangements and compositions specifically for changing voices. Cooper taught many prominent researchers of adolescent voice change, including Don Collins and John Cooksey. …

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Sustainability Of Water And Wastewater Infrastructure: Using A Public-Private Partnership Model For Project Financial Assessment, Rebecca Werner Trotter Jan 2013

Sustainability Of Water And Wastewater Infrastructure: Using A Public-Private Partnership Model For Project Financial Assessment, Rebecca Werner Trotter

Electronic Theses and Dissertations

To supplement current and future budget shortfalls for improvements to water and wastewater infrastructure, Public-Private Partnerships (PPPs or P3) are being advocated by the American Society of Civil Engineers (ASCE) and others as a practical mechanism to ensure financial sustainability. A PPP involves a partnership between a government entity and a concessionaire--consisting of one or more private companies acting as a single, private incorporation--who make an agreement on funding, building, and operating a usually government-provided service, such as drinking water and wastewater infrastructure. This is different from a traditional contract between a government entity and a contractor because the concessionaire …

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Development Of The Strategy To Select Optimum Reflective Cracking Mitigation Methods For The Hot-Mix Asphalt Overlays In Florida, Hamid Maherinia Jan 2013

Development Of The Strategy To Select Optimum Reflective Cracking Mitigation Methods For The Hot-Mix Asphalt Overlays In Florida, Hamid Maherinia

Electronic Theses and Dissertations

Hot Mix Asphalt (HMA) overlay is a major rehabilitation treatment for the existing deteriorated pavements (both flexible and rigid pavements). Reflective cracking (RC) is the most common distress type appearing in the HMA overlays which structurally and functionally degrades the whole pavement structure, especially under high traffic volume. Although many studies have been conducted to identify the best performing RC mitigation technique, the level of success varies from premature failure to good performance in the field. In Florida, Asphalt Rubber Membrane Interlayers (ARMIs) have been used as a RC mitigation technique but its field performance has not been successful. In …

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Analytical And Experimental Study Of Monitoring For Chain-Like Nonlinear Dynamic Systems, Bryan Paul Jan 2013

Analytical And Experimental Study Of Monitoring For Chain-Like Nonlinear Dynamic Systems, Bryan Paul

Electronic Theses and Dissertations

Inverse analysis of nonlinear dynamic systems is an important area of research in the eld of structural health monitoring for civil engineering structures. Structural damage usually involves localized nonlinear behaviors of dynamic systems that evolve into different classes of nonlinearity as well as change system parameter values. Numerous parametric modal analysis techniques (e.g., eigensystem realization algorithm and subspace identification method) have been developed for system identification of multi-degree-of-freedom dynamic systems. However, those methods are usually limited to linear systems and known for poor sensitivity to localized damage. On the other hand, non-parametric identification methods (e.g., artificial neural networks) are advantageous …

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The Effects Of Assumption On Subspace Identification Using Simulation And Experiment Data, Yoonhwak Kim Jan 2013

The Effects Of Assumption On Subspace Identification Using Simulation And Experiment Data, Yoonhwak Kim

Electronic Theses and Dissertations

In the modern dynamic engineering field, experimental dynamics is an important area of study. This area includes structural dynamics, structural control, and structural health monitoring. In experimental dynamics, methods to obtain measured data have seen a great influx of research efforts to develop an accurate and reliable experimental analysis result. A technical challenge is the procurement of informative data that exhibits the desired system information. In many cases, the number of sensors is limited by cost and difficulty of data archive. Furthermore, some informative data has technical difficulty when measuring input force and, even if obtaining the desired data were …

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Chemophysical Characteristics And Application Of Biosorption Activated Media (Bam) For Copper And Nutrient Removal In Stormwater Management, Jamie Jones Jan 2013

Chemophysical Characteristics And Application Of Biosorption Activated Media (Bam) For Copper And Nutrient Removal In Stormwater Management, Jamie Jones

Electronic Theses and Dissertations

For high groundwater table areas, stormwater wet detention ponds are utilized as the preferred stormwater management throughout the state of Florida. Previous research has found that accumulations of nutrients, algae, heavy metals, pesticides, chlorophyll a, fecal coliform bacteria and low concentrations of dissolved oxygen (DO) are common characteristics of stormwater wet detention ponds. Although these pollutant levels are not regulated within the ponds, states are required to compute the pollutant load reductions through total maximum daily load (TMDL) programs to meet the water quality requirements addressed by the Clean Water Act (CWA). In this study, field sampling data of stormwater …

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Multi-Physics Modeling Of Geomechanical Systems With Coupled Hydromechanical Behaviors, Ahmad Mohamed Jan 2013

Multi-Physics Modeling Of Geomechanical Systems With Coupled Hydromechanical Behaviors, Ahmad Mohamed

Electronic Theses and Dissertations

Geotechnical structures under realistic field conditions are usually influenced with complex interactions of coupled hydromechanical behavior of porous materials. In many geotechnical applications, however, these important coupled interactions are ignored in their constitutive models. Under coupled hydromechanical behavior, stress in porous materials causes volumetric change in strain, which causes fluid diffusion; consequently, pore pressure dissipates through the pores that results in the consolidation of porous material. The objective of this research wasto demonstrate the advantages of using hydromechanical models to estimate deformation and pore water pressure of porous materials by comparing with mechanical-only models. Firstly, extensive literature survey was conducted …

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Integrated Data Fusion And Mining (Idfm) Technique For Monitoring Water Quality In Large And Small Lakes, Benjamin Vannah Jan 2013

Integrated Data Fusion And Mining (Idfm) Technique For Monitoring Water Quality In Large And Small Lakes, Benjamin Vannah

Electronic Theses and Dissertations

Monitoring water quality on a near-real-time basis to address water resources management and public health concerns in coupled natural systems and the built environment is by no means an easy task. Furthermore, this emerging societal challenge will continue to grow, due to the ever-increasing anthropogenic impacts upon surface waters. For example, urban growth and agricultural operations have led to an influx of nutrients into surface waters stimulating harmful algal bloom formation, and stormwater runoff from urban areas contributes to the accumulation of total organic carbon (TOC) in surface waters. TOC in surface waters is a known precursor of disinfection byproducts …

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Evaluating The Use Of Recycled Concrete Aggregate In French Drain Applications, Zachary Behring Jan 2013

Evaluating The Use Of Recycled Concrete Aggregate In French Drain Applications, Zachary Behring

Electronic Theses and Dissertations

Recycled concrete aggregate (RCA) is often used as a replacement of virgin aggregate in road foundations (base course), embankments, hot-mix asphalt, and Portland cement concrete. However, the use of RCA in exfiltration drainage systems, such as French drains, is currently prohibited in many states of the U.S. The French drain system collects water runoff from the road pavement and transfers to slotted pipes underground and then filters through coarse aggregate and geotextile. The primary concerns with using RCA as a drainage media are the fines content and the precipitation of calcium carbonate to cause a reducing in filter fabric permittivity. …

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Assessment, Optimization, And Enhancement Of Ultrafiltration (Uf) Membrane Processes In Potable Water Treatment, Christopher Boyd Jan 2013

Assessment, Optimization, And Enhancement Of Ultrafiltration (Uf) Membrane Processes In Potable Water Treatment, Christopher Boyd

Electronic Theses and Dissertations

This dissertation reports on research related to ultrafiltration (UF) membranes in drinking water applications. A pilot-scale investigation identified seasonal surface water quality impacts on UF performance and resulted in the development of a dynamic chemically enhanced backwash protocol for fouling management. Subsequent analysis of UF process data revealed limitations with the use of specific flux, transmembrane pressure (TMP), and other normalization techniques for assessing UF process fouling. A new TMP balance approach is presented that identifies the pressure contribution of membrane fouling and structural changes, enables direct process performance comparisons at different operating fluxes, and distinguishes between physically and chemically …

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Evaluation Of The Biodegradability And Toxicity Of Pca And Mpca, Juan Rueda Jan 2013

Evaluation Of The Biodegradability And Toxicity Of Pca And Mpca, Juan Rueda

Electronic Theses and Dissertations

The main types of hypergolic propellants used at Kennedy Space Center (KSC) are hydrazine (HZ) and monomethylhydrazine (MMH). HZ and MMH are classified as hazardous materials and they are also known to be potentially carcinogenic to humans; therefore, handling these substances and their waste is strictly regulated. The wastes streams from HZ and MMH have been estimated to be the main hazardous wastes streams at KSC. Currently at KSC these wastes are first neutralized using citric acid and then they are transported on public roads for incineration as hazardous materials. A new method using alpha ketoglutaric acid (AKGA) was proposed …

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Development Of A Chemical Kinetic Model For A Fluidized-Bed Sewage Sludge Gasifier, Wyatt Champion Jan 2013

Development Of A Chemical Kinetic Model For A Fluidized-Bed Sewage Sludge Gasifier, Wyatt Champion

Electronic Theses and Dissertations

As the need for both sustainable energy production and waste minimization increases, the gasification of biomass becomes an increasingly important process. What would otherwise be considered waste can now be used as fuel, and the benefits of volume reduction through gasification are seen in the increased lifespan of landfills. Fluidized-bed gasification is a particularly robust technology, and allows for the conversion of most types of waste biomass. Within a fluidized-bed gasifier, thermal medium (sand) is heated to operating temperature (around 1350°F) and begins to fluidize due to the rapid expansion of air entering the bottom of the reactor. This fluidization …

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Near-Road Dispersion Modeling Of Mobile Source Air Toxics (Msats) In Florida, Kurt Westerlund Jan 2013

Near-Road Dispersion Modeling Of Mobile Source Air Toxics (Msats) In Florida, Kurt Westerlund

Electronic Theses and Dissertations

There is a growing public concern that emissions of mobile source air toxics (MSATs) from motor vehicles may pose a threat to human health. At present, no state or federal agencies require dispersion modeling of these compounds, but many agencies are concerned about potential future requirements. Current air pollution professionals are familiar with Federal Highway Administration (FHWA) and U.S. Environmental Protection Agency (EPA) requirements for dispersion modeling to produce predicted concentrations for comparison with appropriate standards. This research examined a method in which the potential near-road concentrations of MSATs were calculated. It was believed that by assessing MSATs in much …

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Study Of The Effect Of Surface Morphology On Mass Transfer And Fouling Behavior Of Reverse Osmosis And Nanofiltration Membrane Processes, Yuming Fang Jan 2013

Study Of The Effect Of Surface Morphology On Mass Transfer And Fouling Behavior Of Reverse Osmosis And Nanofiltration Membrane Processes, Yuming Fang

Electronic Theses and Dissertations

Reverse osmosis (RO) and nanofiltration (NF) membranes are pressure driven, diffusion controlled process. The influence of surface characteristics on membrane process performance is considered significant and is not well understood. Current mass transport models generally assume constant mass transfer coefficients (MTCs) based on a homogeneous surface. This work evaluated mass transfer processes by incorporating surface morphology into a diffusion-based model assuming MTCs are dependent on the thickness variation of the membrane’s active layer. To mathematically create such a surface layer, Gaussian random vectors embedded in a software system (MATLAB) were used to generate a three-dimensional ridge and valley active layer …

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A Systems Approach To Sustainable Energy Portfolio Development, Saeed Hadian Jan 2013

A Systems Approach To Sustainable Energy Portfolio Development, Saeed Hadian

Electronic Theses and Dissertations

Adequate energy supply has become one of the vital components of human development and economic growth of nations. In fact, major components of the global economy such as transportation services, communications, industrial processes, and construction activities are dependent on adequate energy resources. Even mining and extraction of energy resources, including harnessing the forces of nature to produce energy, are dependent on accessibility of sufficient energy in the appropriate form at the desired location. Therefore, energy resource planning and management to provide appropriate energy in terms of both quantity and quality has become a priority at the global level. The increasing …

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Non-Destructive Evaluation Of Concrete Structures Using High Resolution Digital Image And Infrared Thermography Technology, Azusa Watase Jan 2013

Non-Destructive Evaluation Of Concrete Structures Using High Resolution Digital Image And Infrared Thermography Technology, Azusa Watase

Electronic Theses and Dissertations

As existing bridge structures age, they are susceptible to the effects of deterioration, damage and other deleterious processes. These effects hamper the capacity and efficiency of transportation networks and adversely impact local, regional and national economic growth. As a result, bridge authorities and other professionals have become more sensitive to maintenance issues related to this aging infrastructure. While highway bridge condition have been monitored by visual inspection, non-destructive evaluation (NDE) technologies have also been developing and they are expected to be utilized for effective management of highway bridges or other civil infrastructure systems. Efficient use of these technologies saves time …

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Geotechnical Technique To Strengthen Traditional I-Walls Through The Use Of Composite Material, Jimmy Irby Jackson Jan 2013

Geotechnical Technique To Strengthen Traditional I-Walls Through The Use Of Composite Material, Jimmy Irby Jackson

Electronic Theses and Dissertations

On Monday, August 29, 2005, Hurricane Katrina struck the southern gulf coast of the United States. Hurricane Katrina produced record high amounts of surge water along the coastal regions, that over topped and eroded levees and flood walls, inevitably flooding the entire city of New Orleans. After Hurricane Katrina, the Department of Homeland Security approved a research grant to The University of Mississippi to develop effective but economic technique of strengthening existing I-walls. Using composite materials, a new retrofitting technique was developed to increase the stability of existing I-walls by implementing composite caps. For economical and practical testing, scale models …

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Sustainability Analysis Of Intelligent Transportation Systems, Tolga Ercan Jan 2013

Sustainability Analysis Of Intelligent Transportation Systems, Tolga Ercan

Electronic Theses and Dissertations

Commuters in urban areas suffer from traffic congestion on a daily basis. The increasing number of vehicles and vehicle miles traveled (VMT) are exacerbating this congested roadway problem for society. Although literature contains numerous studies that strive to propose solutions to this congestion problem, the problem is still prevalent today. Traffic congestion problem affects society’s quality of life socially, economically, and environmentally. In order to alleviate the unsustainable impacts of the congested roadway problem, Intelligent Transportation Systems (ITS) has been utilized to improve sustainable transportation systems in the world. The purpose of this thesis is to analyze the sustainable impacts …

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A Gis-Based Watershed Impact Management Model, Chioma Nneamaka Udeze Jan 2013

A Gis-Based Watershed Impact Management Model, Chioma Nneamaka Udeze

Electronic Theses and Dissertations

Assessment of land use changes on hydrological processes is essential for the planning and development of sustainable land management practices and water resources. Understanding how land management practices influence hydrological components is essential for the prediction of hydrological consequences of changes in land use. Given the plethora of hydrological models, digital data sources, and the limited availability of observed data, it is difficult to quantify the impacts of land use changes on hydrology. In this study, a Watershed Impact Management (WIM) model framework was conceptualized. A case study of the Yocona River basin, Mississippi, was implemented with the soil and …

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Financial Evaluation Of Milege Based User Fees For Florida's Transportation Funding, Massoud Moradi Jan 2012

Financial Evaluation Of Milege Based User Fees For Florida's Transportation Funding, Massoud Moradi

Electronic Theses and Dissertations

Motor fuel taxes have been collected as a principal source of highway funding for close to a century. They account for approximately two thirds of all the highway user fees and about half of all highway expenditures. Federal fuel taxes have not kept pace with the inflation in general and increasing traffic demand and resulting construction, maintenance and operation costs of the transportation assets in particular. Lack of political will, combined with rising anti-tax sentiment among the populace, has kept the federal tax level not only well below its initial intents, but also at a unsustainable level in future. Mileage …

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Monitoring And Modeling To Estimate Hydrogen Sulfide Emissions And Dispersion From Florida Construction And Demolition Landfills To Construct Odor Buffering Distances, Steven Jeffrey Bolyard Jan 2012

Monitoring And Modeling To Estimate Hydrogen Sulfide Emissions And Dispersion From Florida Construction And Demolition Landfills To Construct Odor Buffering Distances, Steven Jeffrey Bolyard

Electronic Theses and Dissertations

Emissions of hydrogen sulfide (H2S) from construction and demolition (C & D) landfills can result in odors that are a significant nuisance to nearby neighborhoods and businesses. As Florida’s population continues to grow and create development pressures, housing is built closer to existing landfills. Additionally, new landfills will be created in the future. This research project was undertaken to develop a detailed modeling methodology for use by counties and other landfill owners to provide them with an objective and scientifically defensible means to establish odor buffer zones around C & D landfills. A technique for estimating methane (and odorous gas) …

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Land Use Effects On Energy And Water Balance-Developing A Land Use Adapted Drought Index, Chi Han Cheng Jan 2012

Land Use Effects On Energy And Water Balance-Developing A Land Use Adapted Drought Index, Chi Han Cheng

Electronic Theses and Dissertations

Climate change is expected to increase the frequency, intensity and duration of droughts in all parts of the United States (US). Snow packs are disappearing earlier in the spring and summer, with reduced stream-flow. Lower reservoir levels, higher temperatures, and greater precipitation variability have been observed. Drought events in the US have threatened drinking water supplies for communities in Maryland and Chesapeake Bay as observed in 2001 through September 2002; Lake Mead in Las Vegas in 2000 through 2004; Peace River and Lake Okeechobee in South Florida in 2006; and Lake Lanier in Atlanta, Georgia in 2007. ENSO influences the …

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Sustainable Transportation At The University Of Central Florida: Evaluation Of Ucf Rideshare Program, Zimride, Joseph Patrick Defrancisco Jan 2012

Sustainable Transportation At The University Of Central Florida: Evaluation Of Ucf Rideshare Program, Zimride, Joseph Patrick Defrancisco

Electronic Theses and Dissertations

As the second-largest university in the United States, UCF has experienced the largest enrollment in its history. A more densely populated campus has in turn caused increased traffic congestion. Despite increased parking permit fees and newly constructed parking garages, traveling and parking on campus is unpredictable. In effort to reduce congestion on campus, a rideshare program was implemented in Summer 2010. Several universities across the nation have successfully used carpooling as a viable alternative mode to manage traffic and parking demand. This thesis evaluates the UCF rideshare program, Zimride, using stated- and revealed-preference surveys. Preliminary results indicate most students prefer …

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Resilience Of Bridges Following Aftershocks, Diego Francisco Espinosa Jan 2012

Resilience Of Bridges Following Aftershocks, Diego Francisco Espinosa

Electronic Theses and Dissertations

The ability to predict the reduction in capacity of a structure after an earthquake is vital in the process of assessing a structure after a main-shock or an after-shock. Main-shocks are normally followed by a few aftershocks in a short period of time. Researchers in the past have focused for the most part on the effects of main-shocks on buildings. Very little research has been performed on the ability to predict the reduction in capacity of bridges in aftershocks. This thesis focuses on providing a way of assessing the reduction in capacity for main-shocks as compared to aftershocks and the …

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Performance Of Mechanical And Non-Mechanical Connections To Gfrp Components, Nnadozie N. Dike Jan 2012

Performance Of Mechanical And Non-Mechanical Connections To Gfrp Components, Nnadozie N. Dike

Electronic Theses and Dissertations

There are presently many solutions to dealing with aging or deteriorated structures. Depending on the state of the structure, it may need to be completely over-hauled, demolished and replaced, or only specific components may need rehabilitation. In the case of bridges, rehabilitation and maintenance of the decks are critical needs for infrastructure management. Viable rehabilitation options include replacement of decks with aluminum extrusions, hybrid composite and sandwich systems, precast reinforced concrete systems, or the use of pultruded fiber-reinforced polymer (FRP) shapes. Previous research using pultruded glass fiber-reinforced polymer (GFRP) decks, focused on behaviour under various strength and serviceability loading conditions. …

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A Comprehensive Severity Analysis Of Large Vehicle Crashes, Haluk Laman Jan 2012

A Comprehensive Severity Analysis Of Large Vehicle Crashes, Haluk Laman

Electronic Theses and Dissertations

The goal of this thesis is to determine the contributing factors affecting severe traffic crashes (severe: incapacitating and fatal - non-severe: no injury, possible injury, and non-incapacitating), and in particular those factors influencing crashes involving large vehicles (heavy trucks, truck tractors, RVs, and buses). Florida Department of Highway Safety and Motor Vehicles (DHSMV) crash reports of 2008 have been used. The data included 352 fatalities and 9,838 injuries due to large vehicle crashes. Using the crashes involving large vehicles, a model comparison between binary logit model and a Chi-squared Automatic Interaction Detection (CHAID) decision tree model is provided. There were …

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Macroscopic Crash Analysis And Its Implications For Transportation Safety Planning, Chowdhury Kawsar Siddiqui Jan 2012

Macroscopic Crash Analysis And Its Implications For Transportation Safety Planning, Chowdhury Kawsar Siddiqui

Electronic Theses and Dissertations

Incorporating safety into the transportation planning stage, which is often termed as transportation safety planning (TSP), relies on the vital interplay between zone characteristics and zonal traffic crashes. Although a few safety studies had made some effort towards integrating safety and planning, several unresolved problems and a complete framework of TSP are still absent in the literature. This research aims at examining the suitability of the current traffic-related zoning planning process in a new suggested planning method which incorporates safety measures. In order to accomplish this broader research goal, the study defined its research objectives in the following directions towards …

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Multi-Level Safety Performance Functions For High Speed Facilities, Mohamed Ahmed Jan 2012

Multi-Level Safety Performance Functions For High Speed Facilities, Mohamed Ahmed

Electronic Theses and Dissertations

High speed facilities are considered the backbone of any successful transportation system; Interstates, freeways, and expressways carry the majority of daily trips on the transportation network. Although these types of roads are relatively considered the safest among other types of roads, they still experience many crashes, many of which are severe, which not only affect human lives but also can have tremendous economical and social impacts. These facts signify the necessity of enhancing the safety of these high speed facilities to ensure better and efficient operation. Safety problems could be assessed through several approaches that can help in mitigating the …

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