Critical infrastructure systems, such as transportation, energy, water and communication, are the backbones of sustainable economic and social development. The tragedies and catastrophic events in the past few years have motivated researchers to study the vulnerability of infrastructure systems to disastrous events. A number of existing studies address roadway networks where researchers have characterized the robustness and vulnerability of roadways to earthquakes, floods, and targeted attacks. However, extreme events with infrequent return periods are not very likely to occur in a 50-60 year analysis period of roadways, while many roadways are located in areas that are not even exposed to floods or earthquakes at all. On the other hand, roadway network endogenous characteristics such the condition and degradation over time not only increases the vulnerability of roadways to disastrous events, but also makes the roadway network vulnerable to disruptions that are caused by maintenance and repair activities on the roadways system. Nevertheless, the impacts of these endogenous network characteristics on roadway vulnerability have not been explicitly addressed in the existing studies. This dissertation introduces the concept of condition-based vulnerability assessment (CBVA) to capture the effect of roadway endogenous characteristics such as condition and condition uncertainties, roadway network deterioration over time, topological properties of roadways, and travel rate and travel pattern on the dynamics of roadway network vulnerably. First a methodological framework is developed and the method is applied to an illustrative roadway system. The results show that the vulnerability of roadway system is more affected by the average condition of the roadway network than by the condition of individual roads in the system. Moreover, the findings show that small uncertainties associated with the condition of individual roads can significantly increase the variance of the predicated vulnerability. This initial methodological framework is then enhanced to account for physical degradation of the network over time and network equilibrium, and is applied to a real highway system. For the network studied network degradation increases roadway system vulnerability in a nonlinear mode. The result also suggest that the network vulnerability pattern is not very sensitive to travel pattern and link topological properties when the average network disruption probability (representing average network condition) is less than about 0.5. In other words, at low values of average disruption probability, it does not matter what link has what disruption probability level or how the travelers move across the network. However with further network degradation and as the average network disruption probability increases, the dynamics of network vulnerability depends on travel pattern on the network as well as on the link topological properties. / Ph. D.

The United States relies on its vast network of roadways to transport people, goods, and services across the nation. These roads need to be maintained to an acceptable level in order to effectively provide a safe, reliable, and efficient road. The use of infrastructure management systems (IMS) has aided in keeping an inventory of existing roads, identifying assets in need of repair, and assisting in allocating funds for maintenance, repair, and rehabilitation. The current practice in the United States has shown a lack of consistency in the way assets are rated in each state. Individual states have employed their own methodology for rating each asset type. This makes comparison of assets between states difficult. Several methods in use have provided a way to effectively rate an asset, but no method exists that can be used to compare ratings in different states. To successfully maintain the network of roads across the United States, a method to assess assets between states is necessary. Consistency between states in their data collection, rating calculation, and rating reporting are all necessary to identify poor sections of roadway. Another useful reporting item will be a condition rating of all the assets contained within a corridor. A corridor is a series of travel routes which move people between two major points of interest. By analyzing corridor level condition ratings, it will be possible to examine the overall condition of all the corridor sections across the nation and identify sections that need assistance in raising their condition. The objective of this thesis was to develop a framework for rating assets at the corridor level. The framework was developed to be applied to any asset contained within a roadway and allow the combination of individual asset ratings into a single corridor rating. The final methodology not only reports the overall corridor condition, but the functional and structural health of each individual asset, the rating of all of an asset type within a corridor, and performance indicators for individual items on a single asset. The methodology was tested using data provided by the Virginia Department of Transportation (VDOT) to test if the methodology would produce ratings similar to those in use. For the application methods were developed for two major roadway assets; pavements and bridges. The product of this thesis is a general framework which can be applied to roadway corridors to assess the overall condition of all the assets contained within the corridor's boundaries. It can be used in conjunction with an IMS to help improve and maintain the overall condition of the roads, which are critical to the United States. Without unification of condition rating methods into a single method it will never be possible to compare assets from every state in the nation. / Master of Science

Many developing countries have witnessed fast and rapid growth in the last two decades due to the high development rate of economic activity in these countries. Many transportation projects have been constructed. In the same time both population growth and vehicle ownership rate increased; resulting in increasing levels of road crashes. Road traffic crashes in Gulf Cooperation Council (GCC) is considered a serious problem that has deep effects on GCC's population as well as on the national productivity through the loss of lives, injuries, property damage and the loss of valuable resources. From a recent statistical study of traffic crashes in Oman, it was found that in 2013 there were 7,829 crashes occurred for a total of 1,082,996 registered vehicles. These crashes have resulted in 913, 5591, and 1481 fatal, injury and property damage only crashes, respectively (Directorate General of Traffic, 2014), which is considered high rates of fatalities and injuries compared to other more developed countries. This illustrates the seriousness and dangerousness of the safety situation in GCC countries and Oman particularly. Thus, there is an urgent need to alleviate the Severity of the traffic safety problem in GCC which in turn will set a prime example for other developing countries that face similar problems. Two main data sources from Riyadh, the capital city of Kingdom of Saudi Arabia (KSA) and Muscat, the capital city of Sultanate of Oman have been obtained, processed, and utilized in this study. The Riyadh collision and traffic data for this study were obtained in the form of crash database and GIS maps from two main sources: the Higher Commission for the Development of Riyadh (HCDR) and Riyadh Traffic Department (RTD). The Muscat collision and traffic data were obtained from two main sources: the Muscat Municipality (MM) and Royal Oman Police, Directorate General of Traffic (DGC). Since the ARC GIS is still not used for traffic crash geocoding in Oman, the crash data used in the analysis were extracted manually from the filing system in the DGC. Due to the fact that not all developing countries highway agencies possess sufficient crash data that enable the development of robust models, this problem gives rise to the interest of transferability of many of the models and tools developed in the US and other developed nations. The Highway Safety Manual (HSM) is a prime and comprehensive resource recently developed in the US that would have substantial impact if researchers are able to transfer its models to other similar environment in GCC. It would save time, effort, and money. The first edition of the HSM provides a number of safety performance functions (SPFs), which can be used to predict collisions on a roadway network. This dissertation examined the Transferability of HSM SPFs and developing new local models for Riyadh and Muscat. In this study, first, calibration of the HSM SPFs for Urban Four-lane divided roadway segments (U4D) with angle parking in Riyadh and the development of new SPFs were examined. The study calibrates the HSM SPFs using HSM default Crash Modification Factors (CMFs), then new local CMFs is proposed using cross-sectional method, which treats the estimation of calibration factors using fatal and injury data. In addition, new forms for specific SPFs are further evaluated to identify the best model using the Poisson-Gamma regression technique. To investigate how well the safety performance model fits the data set, several performance measures were examined. The performance measures summarize the differences between the observed and predicted values from related SPFs. Results indicate that the jurisdiction-specific SPFs provided the best fit of the data used in this study, and would be the best SPFs for predicting severe collisions in the City of Riyadh. The study finds that the HSM calibration using Riyadh local CMFs outperforms the calibration method using the HSM default values. The HSM calibration application for Riyadh crash conditions highlights the importance to address variability in reporting thresholds. One of the findings of this research is that, while the medians in this study have oversize widths ranging from 16ft-70ft, median width has insignificant effect on fatal and injury crashes. At the same time the frequent angle parking in Riyadh urban road networks seems to increase the fatal and injury collisions by 52 percent. On the other hand, this dissertation examined the calibration of the HSM SPFs for Urban intersections in Riyadh, Kingdom of Saudi Arabia (KSA) and the development of new set of models using three year of collision data (2004-2006) from the city of Riyadh. Three intersection categories were investigated: 3-leg signalized, 4-leg signalized, and 3-leg unsignalized. In addition, new forms for specific SPFs are further evaluated to identify the best model using the Poisson-Gamma regression technique. Results indicate that the new local developed SPFs provided the best fit of the data used in this study, and would be the best SPFs for predicting severe crashes at urban intersections in the City of Riyadh Moreover, this study examined the calibration of the HSM SPFs for Fatal and Injury (FI), Property Damage Only (PDO) and total crashes for Urban Four-lane divided roadway segments (U4D) in Muscat, Sultanate of Oman and the development of new SPFs. This study first calibrates the HSM SPFs using the HSM methodology, and then new forms for specific SPFs are further evaluated for Muscat's urban roads to identify the best model. Finally, Riyadh fatal and injury model were validated using Muscat FI dataset. Comparisons across the models indicate that HSM calibrated models are superior with a better model fit and would be the best SPFs for predicting collisions in the City of Muscat. The best developed collision model describes the mean crash frequency as a function of natural logarithm of the annual average daily traffic, segment length, and speed limit. The study finds that the differences in road geometric design features and FI collision characteristics between Riyadh and Muscat resulted in an un-transferable Riyadh crash prediction model. Overall, this study lays an important foundation towards the implementation of HSM methods in multiple cities (Riyadh and Muscat), and could help their transportation officials to make informed decisions regarding road safety programs. The implications of the results are extendible to other cities and countries and the region, and perhaps other developing countries as well.

<p>Ultrafine particles (UFP) emitted by traffic have been associated with health risks for people living and working near major roadways. Studies have shown that people living in near-roadway communities experience higher risk of aggravated asthma, respiratory diseases and even childhood leukemia. Sharp concentration gradients of UFP have been reported near major highways with the concentration decreasing rapidly away from the road. Dispersion of UFP downwind of a road depends on many parameters, such as the atmospheric stability and wind speed. Presence of different structures such as noise barriers and vegetation can greatly influence the dispersion and downwind concentrations of UFP. These structures can block the traffic emissions and increase vertical mixing. In addition, vegetation can reduce UFP by deposition processes. Two sets of experiments were conducted in this thesis to investigate the effect of barriers on UFP deposition and dispersion. </p><p>The first set of experiments was performed in a wind tunnel facility to address UFP deposition to vegetation barriers solely. Two analytical models were proposed to characterize UFP dry deposition to vegetation measured during the wind tunnel experiment. The first model was derived from the filtration theory to explain UFP dry deposition to pine and juniper branches. The model agrees well with the experimental data indicating that pine and juniper branches can be treated as fibrous filters. The fiber diameters of pine derived from the experimental data were also similar to the physical diameters of pine needles; thus, providing further evidence that vegetation can be regarded as fibers. The second model was derived from the continuity equation and can predict the branch-scale dry deposition of UFP using conventional canopy properties such as the drag coefficient and leaf area density. Both models agree with the measurement results to within 20%.</p><p>The second set of experiments was done in three near-roadway environments to investigate the effects of barriers on the dispersion and dry deposition of UFP. We used mobile and stationary measurements to obtain the spatial and temporal variability of UFP. Both mobile and stationary measurements indicated that vegetation and noise barriers can reduce downwind UFP concentrations through dispersion and dry deposition by 20-60 %. </p><p>In conclusion, the effect of barriers on UFP dispersion and deposition has been characterized in this thesis. Two analytical models were also proposed from the wind tunnel experiments to characterize dry deposition and agreed well with the measurement results. The analytical model could benefit future climate and air quality models.</p> / Dissertation

A aquaplanagem é um fenômeno que pode ocasionar riscos de acidentes em pistas rodoviárias e que consiste na perda de aderência entre os pneus de um veículo e a superfície do pavimento, em decorrência da presença de uma película de água com certa espessura que impede o contato entre ambos, situação essa que pode ser gerada em condições de precipitações pluviométricas de intensidades relativamente elevadas. De uma forma geral tal fenômeno é desconsiderado em normas, manuais e especificações para projetos rodoviários, tanto no Brasil como no Exterior. O presente trabalho tem como objetivo básico a proposição de um procedimento metodológico que permita a identificação de trechos de traçados rodoviários nos quais tal fenômeno possa ocorrer, seja na fase de elaboração de projetos, seja no processo de avaliação das condições de segurança de pistas existentes. O procedimento proposto foi estruturado com base na análise dos principais modelos de previsão de risco de aquaplanagem levantados durante a revisão bibliográfica, bem como em uma extensiva análise das principais variáveis que influenciam esse fenômeno. Com o propósito de avaliar a adequabilidade do procedimento proposto foi elaborado um estudo de caso considerando as características geométricas e dados pluviométricos relativos a determinada extensão do Trecho Leste do Rodoanel de São Paulo. Em tal estudo de caso foram apresentadas proposições de soluções alternativas de mitigação de risco para os trechos identificados como locais com possibilidade de ocorrência de aquaplanagem. / Hydroplaning is a phenomenon that can result in hazard risk on highways, its occurrence is defined by an absence of adherence between the tire and the pavement caused by the presence of a water film of a certain depth that hinder the contact between those surfaces, it\'s occurrence is related to high rainfall intensity situations. Usually highway design manuals, standards and criteria don\'t consider the occurrence of this phenomenon, in Brazil or abroad. The present work has the object of proposing a methodological procedure that allows for the identification of highway segments that are subject to hydroplaning, during its design or during the evaluation of its security conditions. The proposed procedure was based on the analysis of the hydroplaning prediction models studied during the bibliography review, as well as in an extensive analysis of the main variables influencing its occurrence. For the evaluation of the proposed procedure, a case study was conducted with the east portion of the \"Rodoanel Mario Covas\" geometric characteristics and pluviometry data. In this study some risk mitigation proposals were evaluated for the extensions on which were identified the possibility of hydroplaning occurrence.

A aquaplanagem é um fenômeno que pode ocasionar riscos de acidentes em pistas rodoviárias e que consiste na perda de aderência entre os pneus de um veículo e a superfície do pavimento, em decorrência da presença de uma película de água com certa espessura que impede o contato entre ambos, situação essa que pode ser gerada em condições de precipitações pluviométricas de intensidades relativamente elevadas. De uma forma geral tal fenômeno é desconsiderado em normas, manuais e especificações para projetos rodoviários, tanto no Brasil como no Exterior. O presente trabalho tem como objetivo básico a proposição de um procedimento metodológico que permita a identificação de trechos de traçados rodoviários nos quais tal fenômeno possa ocorrer, seja na fase de elaboração de projetos, seja no processo de avaliação das condições de segurança de pistas existentes. O procedimento proposto foi estruturado com base na análise dos principais modelos de previsão de risco de aquaplanagem levantados durante a revisão bibliográfica, bem como em uma extensiva análise das principais variáveis que influenciam esse fenômeno. Com o propósito de avaliar a adequabilidade do procedimento proposto foi elaborado um estudo de caso considerando as características geométricas e dados pluviométricos relativos a determinada extensão do Trecho Leste do Rodoanel de São Paulo. Em tal estudo de caso foram apresentadas proposições de soluções alternativas de mitigação de risco para os trechos identificados como locais com possibilidade de ocorrência de aquaplanagem. / Hydroplaning is a phenomenon that can result in hazard risk on highways, its occurrence is defined by an absence of adherence between the tire and the pavement caused by the presence of a water film of a certain depth that hinder the contact between those surfaces, it\'s occurrence is related to high rainfall intensity situations. Usually highway design manuals, standards and criteria don\'t consider the occurrence of this phenomenon, in Brazil or abroad. The present work has the object of proposing a methodological procedure that allows for the identification of highway segments that are subject to hydroplaning, during its design or during the evaluation of its security conditions. The proposed procedure was based on the analysis of the hydroplaning prediction models studied during the bibliography review, as well as in an extensive analysis of the main variables influencing its occurrence. For the evaluation of the proposed procedure, a case study was conducted with the east portion of the \"Rodoanel Mario Covas\" geometric characteristics and pluviometry data. In this study some risk mitigation proposals were evaluated for the extensions on which were identified the possibility of hydroplaning occurrence.

Road crashes are one of the main causes of death in the United States. To reduce the number of accidents, roadway assessment programs take a proactive approach, collecting data and identifying high-risk roads before crashes occur. However, the cost of data acquisition and manual annotation has restricted the effect of these programs. In this thesis, we propose methods to automate the task of roadway safety assessment using deep learning. Specifically, we trained convolutional neural networks on publicly available roadway images to predict safety-related metrics: the star rating score and free-flow speed. Inference speeds for our methods are mere milliseconds, enabling large-scale roadway study at a fraction of the cost of manual approaches.

Electric vehicles represent a major accomplishment in the energy and transportation industry. Unfortunately, they are restricted to a small travel range because of limited battery life. Successful integration of wireless power transfer (WPT) systems into the infrastructure would remove the range restrictions of EVs. To successfully integrate this technology, several requirements must be met. First, the embedment process cannot interfere with the electrical performance of the inductive power transfer (IPT) system. Second, the presence of the IPT system in the pavement structure cannot negatively affect the roadway’s lifespan. Several systems were directly embedded in roadway materials. The electrical properties of the systems were monitored during the embedment process. Then modifications were made to the IPT systems to optimize the embedment process. These modifications were then applied to a full scale IPT system which is being used to dynamically charge EVs. To test the structural performance of the systems, tensile stresses were applied to the pads to simulate traffic loading conditions. These tensile stresses were applied under cyclic loading conditions to simulate fatigue conditions found in roadways. The number of cycles, and stress at failure was recorded an analyzed. The electrical properties of the IPT pads was also measured and analyzed during the fatigue loading conditions.

Multiple distribution travel time data has been observed in signalized corridors as well as freeway corridors. This behavior is typically caused by congestion, uncoordinated signals, or routes through a coordinated corridor that are not a priority. On the SR140 corridor near the Jimmy Carter Boulevard / I-85 Interchange, it was found that the travel times recorded on the corridor contained multiple distributions and thus a methodology was sought to properly separate the distributions in order to perform more robust statistical analysis. Next, an R statistical language library was found, called “mixtools”, which contained a multiple gamma distribution fitting function called “gammamixEM”. Gamma distributions were chosen for this application as typical travel time distributions tend contain a one sided tail. This function was used in conjunction with a monte-carlo approach to find fits for one to six distributions. The accuracy of the fit was confirmed through visual inspection of the plotted distributions. Then, the Akaike Information Criteria were used to compare the fits to determine the best fit number of distributions. This thesis contains a detailed outline of the algorithm as well as results from the algorithm for the combined Tuesday dataset from this project. It was found that the approach worked well for 60 out of 70 cases. In the 10 cases that were not ideal, the distributional fits make sense on a statistical level, however, for the purposes of the before and after project the next best Akaike Information Criteria value fit may need to used. These 10 cases tended to split obvious single distributions into two distributions, which is not desirable in a before and after analysis where one is not only testing individual distributions before and after construction but also determining if distributions were created or removed as a result of the change in operation of the interchange.

A critical part of traffic safety is a driver’s ability to detect and respond to emergency roadway hazards. This thesis uses eye movements and motor responses to divide driver perception-response time in three stages: perception, inspection, and movement time. The effects of cognitive distraction and repeated exposure on each stage were investigated for three distinct hazards (left-turning vehicle, pedestrian, right-incursion vehicle). In general, there were varying effects of cognitive distraction observed depending on the hazard being responded to. Cognitive distraction resulted in a significant increase in perception times for the pedestrian and right-incursion vehicle hazards, whereas cognitive distraction resulted in significantly longer inspection times for the left-turning vehicle hazard. When considering the effect of repeated scenario exposure, perception times were the most greatly affected. Perception times were significantly shorter during the second exposure to the left-turning vehicle hazard in the baseline condition, and for all hazards in the distraction condition.