Submitted by JOÃO RAFAEL DE CONTE CARVALHO DE ALENCAR (jralencar@gmail.com) on 2016-08-02T21:26:02Z No. of bitstreams: 1 Tese Completa João 31-06-2016.pdf: 1972389 bytes, checksum: 65cb391e11ab0faad1c090aead364836 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-04T18:22:56Z (GMT) No. of bitstreams: 1 alencar_jrdcc_dr_jabo.pdf: 1972389 bytes, checksum: 65cb391e11ab0faad1c090aead364836 (MD5) / Made available in DSpace on 2016-08-04T18:22:56Z (GMT). No. of bitstreams: 1 alencar_jrdcc_dr_jabo.pdf: 1972389 bytes, checksum: 65cb391e11ab0faad1c090aead364836 (MD5) Previous issue date: 2016-07-04 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A cana-de-açúcar é uma das principais culturas do Brasil em área e produção, lhe conferindo problemas fitossanitários em igual proporção. Dentre estes problemas os insetos-praga acabam por limitar a produtividade. Sphenophorus levis é conhecido como uma das principais pragas da cana-de-açúcar. O gorgulho-da-cana tem a amostragem e o controle difíceis de serem realizados devido ao seu hábito subterrâneo durante as fases iniciais de desenvolvimento. Este trabalho, portanto teve como objetivo estudar a dinâmica populacional. o padrão de distribuição e desenvolver um plano de amostragem sequencial de S. levis na cultura da cana-de-açúcar. Foram levantados dados da praga em uma área de 1,05 hectares entre o segundo e o terceiro corte da cultura, em duas safras seguidas 2013/2014 e 2014/2015. As áreas foram divididas em 100 parcelas onde se realizou a contagem de larvas, pupas e adultos, soma das formas biológicas e rizomas atacados pelo gorgulho da cana. Para isso, foram amostradas duas trincheiras por parcela de 0,5 x 0,5 x 0,5 m (largura, altura e profundidade) a cada duas semanas. E para os adultos também foi usado armadilhas com toletes tratados com melaço de cana. Com estes dados coletados foi possível verificar satisfatoriamente a praga e seus danos, e constatar que eles permanecem o ano inteiro presentes na área de cultivo. Além disso, foi determinado os períodos em que cada fase de desenvolvimento ocorram com maior e menor incidência, e correlacionar estes dados aos fatores do clima como a temperatura máxima, média e mínima, precipitação e umidade relativa do ar. Através do método “stepwise” foi constatado que a temperatura mínima, precipitação e umidade relativa do ar, são as variáveis climáticas que mais interferem no desenvolvimento de S. levis. Quanto à distribuição espacial, foi notório que tantos os índices de dispersão estudados, razão variância/média, índice de Morisita, coeficiente de Green e o expoente k da distribuição binomial negativa, indicaram que o gorgulho-da-cana e seus danos são altamente agregados. Este resultado foi confirmado com o melhor ajuste ao modelo probabilístico de distribuição pelo teste do qui-quadrado da distribuição binomial negativa. Além disso, foi estimado o k comum para desenvolver o plano de amostragem sequencial para os rizomas atacados por S. levis, utilizando-se os dados do teste da razão da máxima verossimilhança, com nível de controle de 10 e 5% de rizomas atacados, com número máximo de unidades amostrais esperado de 21 trincheiras. / The sugarcane is one of the main Brazilian crops in area as well in production. This fact ensures major phytosanitary problems associated too. Among these problems pests end up limiting production in several areas. Sphenophorus levis is known as one of the major pests of sugar cane. The sugarcane weevil sampling and control are difficult to done due their subterranean habit during the early stages of life. Therefore, this work aimed to study the population dynamics, the distribution pattern and to develop a sequential sampling plan for S. levis in sugarcane crops. Pest's data were raised from areas of 1.05 hectares between the second and third harvest cycle in two crops, 2013/2014 and 2014/2015. The areas were divided into 100 plots, where was held the counting of larval, pupae, adults and sum of biological forms from the weevil. The rhizomes attacked by this pest were also counted. For this, were sampled two trenches of 0.5 x 0.5 x 0.5 m (width, height and depth) every two weeks. Also, the adults were collected with pieces of sugarcane treated with molasses in traps. With these collected data was possible to check satisfactorily that the pest and its damage still present for all the crop. In Addition, it was Determined the periods of each development phase, occurring with greater and lesser incidence. Maximum, medial and minimal temperature, such as precipitation and relative humidity were correlated by stepwise method with the dynamics of the pest and its damage. It was found that the minimum temperature, precipitation and relative humidity, are climate variables that most affect the development of S. levis The dispersion indexes studied were variance/mean ratio, Morisita index, Green coefficient and the exponent k of the negative binomial distribution. They indicated that the sugarcane weevil and their damage are highly aggregated. This result was confirmed by the greater fit to the probabilistic distribution model, using the chi-square test for the negative binomial distribution adjustment. Also, it was estimated the common k to develop the sequential sampling plan for attacked rhizomes, using the ratio from the maximum likelihood test data , with 10 and 5 % level of control. The maximum number of sample units expected for Attacked rhizomes was 21 trenches.

Promover a segurança viária no entorno escolar é uma estratégia que contribui para que sejam construídas cidades seguras, saudáveis e sustentáveis. Nesse sentido, este estudo é dedicado a identificar a influência das características da estrutura urbana na frequência e na severidade dos acidentes no entorno de escolas de educação básica de Porto Alegre. A análise da frequência e da severidade de acidentes foi conduzida através da estimação de modelos econométricos: binomial negativo e logit ordenado, respectivamente. Para esses, foram calculados os efeitos marginais, permitindo a observação da magnitude dos impactos das variáveis explicativas sobre as variáveis dependentes. As variáveis dependentes frequência e severidade foram extraídas dos acidentes registrados em Porto Alegre entre 2012 e 2014. Foram incluídas, simultaneamente, variáveis da estrutura urbana, das escolas, socioeconômicas e dos acidentes (para a severidade). A partir do geoprocessamento dos dados existentes, os entornos escolares puderam ser caracterizados para três diferentes áreas circulares de análise (buffer ring) de raios de 100, 150 e 200 metros, permitindo a comparação do uso das diferentes áreas. O conjunto de estimativas indica que áreas menores produzem modelos de melhor desempenho para ambas as técnicas empregadas. No entanto, áreas maiores permitem a análise de maior quantidade de variáveis relativas à estrutura urbana. Essa relação sugere os benefícios da escolha a partir do trade-off entre ajuste do modelo e sua capacidade de propiciar análises de variáveis. Foi identificado que a frequência e a severidade de acidentes podem estar relacionadas a uma única variável explicativa de formas opostas – a partir de sinais contrários. Essa diferença de resultados para frequência e severidade de acidentes indica que há maiores benefícios em analisá-las em conjunto. Identificou-se ainda que existem benefícios para a segurança viária em áreas de estrutura urbana com quarteirões menores e maior quantidade de interseções de quatro vias, em frequência e severidade, respectivamente. Já as áreas mais arborizadas tendem a apresentar acidentes de menor severidade nos casos de usuários de modos ativos. / Fostering road safety nearby schools is a strategy that contributes to build safe, healthy and sustainable cities. The aim of this study is to identify the influence of the built environment characteristics in the frequency and severity of accidents nearby elementary and secondary schools in Porto Alegre. The frequency and severity of the accidents were analyzed using econometric models: negative binomial and ordered logit, respectively. The evaluation of their marginal effects allowed the magnitude of the impact caused by the explanatory variable on the dependent variables to be observed. The measured variables frequency and severity were extracted from accidents registered in Porto Alegre from 2012 and 2014. Built environment, socioeconomic and school variables were also included, as well as accident data (for severity). Data geoprocessing allowed school surroundings to be characterized for three different buffer rings, measuring 100, 150 and 200 meters of radius. Thereby it was possible to compare the inclusion of different areas in the study. The estimations indicates that models based on smaller areas have better performances for both employed techniques, whereas larger areas allow the study of a bigger quantity of urban infrastructure variables. That indicates the benefits of choosing based on a trade-off between model adjustment and capacity to engender the analysis of variables. It was shown that frequency and severity of accidents could be related to a single explanatory variable in opposite ways – based on contrary signs. This difference in the results found for frequency and severity indicates that there are more benefits when analyzing them together. Moreover, there are benefits for road safety in areas where the city blocks are shorter and where there are more four-way intersections, in frequency and severity of accidents, respectively. Also, areas of more important afforestation tend to decrease the severity of accidents involving users of active modes.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-04-23T14:13:46Z No. of bitstreams: 2 Dissertação - Tiago Carvalhais de Oliveira - 2014.pdf: 2283233 bytes, checksum: 6e0744d8d8b25db17ecedc5ed707eee8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-04-23T14:16:09Z (GMT) No. of bitstreams: 2 Dissertação - Tiago Carvalhais de Oliveira - 2014.pdf: 2283233 bytes, checksum: 6e0744d8d8b25db17ecedc5ed707eee8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-04-23T14:16:09Z (GMT). No. of bitstreams: 2 Dissertação - Tiago Carvalhais de Oliveira - 2014.pdf: 2283233 bytes, checksum: 6e0744d8d8b25db17ecedc5ed707eee8 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Caterpillars defoliators of soybean occurs in different times and feed on different parts of the plant, mainly in flowers and pods. During the growing seasons of 2011/2012 and 2012/2013, soybean fields were sampled in different crop phenological stages with the objective of knowing the population fluctuation of the main species of caterpillar defoliating soybeans and to determine the within field spatial distribution of the species of the Plusiinae complex, to describe how species colonize the soybean field. Five commercial fields submitted to different management practices were monitored. Sampling meshes were fabricated with equidistant points 50 meters. The areas were sampled weekly from the occurrence of the first defoliating caterpillars, until close to harvest. The sampling method used was ground cloth, with one row-meter. It was quantified all caterpillars. Data were submitted to statistical analysis using the following SAS procedures: Proc Univariate, Proc Means, Proc Freq. To test what statistical distribution fit to caterpillars population the procedure Proc Genmode was used. Maps representing the localization of samples of caterpillars in soybean fields were constructed. The species of Plusiinae predominated in the area, corresponding to 52, 04% in 2011/2012 e 48, 53% in 2012/2013 of the total of caterpillars found in the reproductive phase of soybean. The distribution of the complex of Plusiinae within field is random and do not present border effect. In this study, while the population fits the negative binomial distribution maps clearly indicate that the caterpillars are randomly dispersed in soybean fields. / As lagartas desfolhadoras da soja ocorrem em épocas distintas e atacam várias partes da planta, principalmente as folhas, flores e frutos. Durante os anos agrícolas de 2011/2012 e 2012/2013, campos de soja foram amostrados em diversos estádios fenológicos da planta com o objetivo de conhecer a flutuação populacional das principais espécies de lagartas desfolhadoras da cultura, e determinar a distribuição espacial em lavoura, espécies pertencentes ao complexo de Plusiinae, para compreender a forma que este complexo coloniza os campos de soja. Foram monitoradas cinco lavouras comerciais, submetidas a diferentes condições de manejo. Foram confeccionadas malhas de amostragem, com pontos eqüidistantes de 50 metros. As áreas foram amostradas semanalmente a partir da ocorrência das primeiras lagartas desfolhadoras, até próximo à colheita. O método de amostragem utilizado foi o pano de batida, com o qual um metro linear foi amostrado. Foram quantificadas todas as lagartas presentes nas amostragens dos campos selecionados. Para a realização das inferências, dos dados foram submetidos á análises estatísticas descritivas utilizando os seguintes procedimentos dos Sas, Proc Univariate, Proc Means e Proc Freq. Para verificar qual a distribuição estatística a que a população de lagartas melhor se ajustava foi utilizado o procedimento Proc Genmode. Mapas representativos da localização das lagartas do complexo Plusiinae no campo foram confeccionados. As espécies de Plusiinae foram as lagartas predominantes, compondo 52,04% em 2011/12 e 48,53% em 2012/13, do total de lagartas encontradas. As flutuações populacionais demonstraram que o pico das lagartas desfolhadoras ocorre principalmente na fase reprodutiva da cultura da soja. A distribuição de lagartas do complexo Plusiinae em lavoura é aleatória, não apresentando efeitos de bordas. Neste estudo, enquanto a população se ajusta à distribuição binomial negativa os mapas indicam claramente que as lagartas estão aleatoriamente dispersas nos campos de soja.

Uma suposição muito comum na análise de modelos de regressão é a de respostas independentes. No entanto, quando trabalhamos com dados longitudinais ou agrupados essa suposição pode não fazer sentido. Para resolver esse problema existem diversas metodologias, e talvez a mais conhecida, no contexto não Gaussiano, é a metodologia de Equações de Estimação Generalizadas (EEGs), que possui similaridades com os Modelos Lineares Generalizados (MLGs). Essas similaridades envolvem a classificação do modelo em torno de distribuições da família exponencial e da especificação de uma função de variância. A única diferença é que nessa função também é inserida uma matriz trabalho que inclui a parametrização da estrutura de correlação dentro das unidades experimentais. O principal objetivo desta dissertação é estudar como esses modelos se comportam em uma situação específica, de dados de contagem com sobredispersão. Quando trabalhamos com MLGs esse problema é resolvido através do ajuste de um modelo com resposta binomial negativa (BN), e a ideia é a mesma para os modelos envolvendo EEGs. Essa dissertação visa rever as teorias existentes em EEGs no geral e para o caso específico quando a resposta marginal é BN, e além disso mostrar como essa metodologia se aplica na prática, com três exemplos diferentes de dados correlacionados com respostas de contagem. / An assumption that is common in the analysis of regression models is that of independent responses. However, when working with longitudinal or grouped data this assumption may not have sense. To solve this problem there are several methods, but perhaps the best known, in the non Gaussian context, is the one based on Generalized Estimating Equations (GEE), which has similarities with Generalized Linear Models (GLM). Such similarities involve the classification of the model around the exponential family and the specification of a variance function. The only diference is that in this function is also inserted a working correlation matrix concerning the correlations within the experimental units. The main objective of this dissertation is to study how these models behave in a specific situation, which is the one on count data with overdispersion. When we work with GLM this kind of problem is solved by setting a model with a negative binomial response (NB), and the idea is the same for the GEE methodology. This dissertation aims to review in general the GEE methodology and for the specific case when the responses follow marginal negative binomial distributions. In addition, we show how this methodology is applied in practice, with three examples of correlated data with count responses.

[pt] O presente trabalho tem como objetivo principal investigar por meio de simulação Monte Carlo algumas propriedades estatísticas dos modelos GARMA (Generalized Autoregressive Moving Average) para séries temporais de dados de contagem. Os modelos GARMA são uma extensão dos Modelos Lineares Generalizados de McCullagh e Nelder para situações de dados dependentes, caracterizando-se pela adição de um termo extra ao preditor linear, o qual passa a incorporar termos autoregressivos (AR) e de médias móveis (MA). As propriedades estatísticas investigadas foram às condições de estacionariedade dos modelos GARMA e os critérios de identificação da ordem (p,q) dos polinômios AR e MA que definem o modelo. Os resultados encontrados indicam que os critérios AIC BIC e Hannan-Quin utilizados foram razoavelmente eficazes na identificação da ordem dos modelos e que as condições de estacionariedade estabelecidas empiricamente em termo de restrições no espaço paramétrico são bastante complexas exigindo um estudo mais detalhado. Como objetivo secundário testamos os modelo GARMA em séries reais, ajustando os modelos GARMA- Poissson e GARMA-Binomial Negativa ao número de caso de poliomielite nos EUA e ao número de infartos do miocárdio no município do Rio de Janeiro. Os resultados indicam que os modelos foram capazes de explicar, de forma econômica, a variação destas séries. / [en] The main objective of this dissertation is to investigate, using Monte Carlo simulations, some statistical properties of GARMA (Generalized Autoregressive Moving Average ) models for time series of count data. GARMA models are extensions of the Generalized Linear Models to dependent data, in which autoregressive (AR) and/or moving average (MA) terms are incorporated into the linear predictor. The statistical properties targeted in our investigation were the model stationarity conditions and the identification criteria for selection of model orders, the lag structure (p,q) associated with the AR and MA terms. Our results suggest that AIC, BIC and Hann-Quinn criteria worked relatively well in identifying the model order, and that the conditions for stationarity established empirically in terms of parameter space restrictions were not totally conclusive, requiring further investigation. As a secondary objective we tested the model against real data, by fitting both a GARMA-Poisson and a GARMA-Negative Binomial to the series of number of cases of poliomyelitis on the US and the number of heart-attacks in Rio de Janeiro city. The results we found indicate that these models were able to explain, in a parsimonious way, the variation of both series.

Although mosquito monitoring systems in the form of dry-ice bated CDC light traps and sentinel chickens are used by mosquito control personnel in Polk County, Florida, the placement of these are random and do not necessarily reflect prevalent areas of vector mosquito populations. This can result in significant health, economic, and social impacts during disease outbreaks. Of these vector mosquitoes Culex nigripalpus, Culex erraticus, Coquillettidia perturbans, and Aedes vexans are present in Polk County and known to transmit multiple diseases, posing a public health concern. This study seeks to evaluate the effect of Land use Land cover (LULC) unique features and precipitation on spatial and temporal distribution of Cx. nigripalpus, Cx. erraticus, Cq. perturbans, and Ae. vexans in Polk County, Florida, during 2013 and 2014, using negative binomial regression on count data from eight environmentally unique light traps retrieved from Polk County Mosquito Control. The negative binomial regression revealed a statistical association among mosquito species for precipitation and LULC features during the two-year study period, with precipitation proving to be the most significant factor in mosquito count numbers. The findings from this study can aid in more precise targeting of mosquito species, saving time and resources on already stressed public health services.

The aim of this study is to examine the effects of a market-based greenhouse gases price on green innovation by testing the Hicksian theory of induced innovation. To test whether causality exists, panel data compiled of 30 countries over 13 years (2005-2017) have been used. The study is restricted to the European Union emission trading scheme, where the price of EUA has been used as a market-based price for greenhouse gases. To capture the effect on innovation, an approximation for innovation in the form of patent counts have been employed using the patent category Y02 constructed by the EPO. The result suggests that green innovation is affected by the price of the EUA, total CO2 emissions and tax revenue from energy. This study employed a knowledge stock variable that was not found to be significant, contrary to previous literature on induced innovation. The incidence rate ratio associated with the  permits price indicates that a one euro increase in price would result in a 1.135 % increase in the patenting of green technology. The result suggests that a higher price in  permits would stimulate innovation of green technology within the European Union.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy. Johannesburg 2016 / Quantifying risk in the absence of hard data presents a significant challenge. Onshore mining of the diamondiferous linear beach deposit along the south western coast of Namibia has been ongoing for more than 80 years. A historical delineated campaign from the 1930s to 1960s used coast perpendicular trenches spaced 500 m apart, comprising a total of 26 000 individual samples, to identify 6 onshore raised beaches. These linear beaches extend offshore and are successfully mined in water depths deeper than 30 m. There is, however, a roughly 4 km wide submerged coast parallel strip adjacent to the mostly mined out onshore beaches for which no real hard data is available at present. The submerged beaches within the 4 km coast parallel strip hold great potential for being highly diamondiferous. To date hard data is not yet available to quantify or validate this potential. The question is how to obtain sufficient hard data within the techno economic constraints to enable a resource with an acceptable level of confidence to be developed. The work presented in this thesis illustrates how virtual orebodies (VOBs) are created based on geological proxies in order to have a basis to assess and rank different sampling and drilling strategies. Overview of 4 papers Paper I demonstrates the challenge of obtaining a realistic variogram that can be used in variogram-based geostatistical simulations. Simulated annealing is used to unfold the coastline and improve the detectable variography for a number of the beaches. Paper II shows how expert opinion interpretation is used to supplement sparse data that is utilised to create an indicator simulation to study the presence and absence of diamondiferous gravel. When only the sparse data is used the resultant simulation is unsuitable as a VOB upon which drilling strategies can be assessed. Paper III outlines how expert opinion hand sketches are used to create a VOB. The composite probability map based on geological proxies is adjusted using a grade profile based on adjacent onshore data before it is seeded with stones and used as a VOB for strategy testing. Paper IV illustrates how the Nachman model based on a Negative Binomial Distribution (NBD) is used to predict a minimum background grade by considering only the zero proportions (Zp) of the grade data. v Conclusions and future work In the realm of creating spatial simulations that can serve as VOBs it is very difficult to attempt to quantify uncertainty when no hard data is available. In the absence of hard data, geological proxies and expert opinion are the only inputs that can be used to create VOBs. Subsequently these VOBs are used as a base to be analysed in order to evaluate and rank different sampling and drilling strategies based on techno economic constraints. VOBs must be updated and reviewed as hard data becomes available after which sampling strategies should be reassessed. During early stage exploration projects the Zp of sample results can be used to predict a minimum background grade and rank different targets for further sampling and valuation. The research highlights the possibility that multi point statistics (MPS) can be used. Higher order MPS should be further investigated as an additional method for creating VOBs upon which sampling strategies can be assessed. / MT2017

A high percentage of highway crashes in the United States occur at intersections. These crashes result in property damage, lost productivity, injury, and even death. Identifying intersections associated with high crash rate is very important to minimize future crashes. The purpose of this study is to develop efficient means to evaluate intersections, which may require safety improvements. The area covered by the analysis in this thesis includes Orange and Seminole Counties and the City of Orlando. The aforementioned counties and city thus represent Central Florida. Each County/City provided data that consisted of signalized intersection drawings that were either in the form of electronic or hard copies, the county's extensive crash database and a list of intersections that underwent modifications during the study period. A total of 786 intersections were used in the analysis and the crash database was made up of 4271 crashes. From the signalized intersection drawings obtained from the county's traffic engineering department, a geometry database was created to classify all intersections by the number of through lanes, number of left turning lanes, Average Annual Daily Traffic and Posted Speed limits on the Major road of the intersection. In this research, crashes and their type, e.g., rear-end, left-turn and angle as well as total crashes were investigated. Numerous models were developed first using the Poisson regression and then using the Negative Binomial approach as the data showed overdispersion. The modeling process aimed to relate geometric and traffic factors to the frequency of crashes at intersections. Expected value analysis tables were also developed to determine if an intersection had an abnormally high number of crashes. These tables can be used in assisting Traffic Engineers in identifying serious safety problems at intersections. The general models illustrated that rear-end crashes were associated with high natural logarithm of AADT on the major road and the number of lanes (major intersections, e.g. 6x4/6x6), whereas AADT on the major road did not affect left-turn crashes. Intersections with the configuration 4x2/6x2 (2 through lanes at the minor roadway) or T intersections as another category experienced an increase in left-turn crashes. Angle crashes were most frequent at one-way intersections especially in the case of 4x4 intersections. Individual models that included interaction terms with one variable at a time concluded that AADT on the major road positively influenced rear-end crashes more compared to angle and left-turn crashes. As the speed increases on the minor road, the left turn crashes are affected more when compared to angle and rear-end crashes, therefore it can be concluded that left-turn crashes are most influenced by the speed limit on the minor road compared to angle crashes and then followed by rear-end crashes. As the total number of left turn lanes increased at the intersection, thereby increasing the size of the intersection, the number of rear-end crashes increased. An overall model that contained natural logarithm of AADT on major road, total number of left turn lanes at the intersection, number of through lanes on the minor road and configuration of the intersection, as independent variables, along with interaction terms, further concluded and supported the individual models that the number of crashes (rear-end, left-turn and angle) increased as the AADT on the major road increased and the number of crashes decreased as the total number of left turn lanes at the intersection increased. Also, crashes increased as the number of through lanes on the minor road increased. The variables' interaction effects with dummies representing rear-end and left-turn crashes in the final model showed that as the AADT on the major road increased, the number of rear-end crashes increased compared to left-turn and angle crashes and also that as the total number of left turn lanes at the intersection increased, the number of left-turn crashes decreased when compared to rear-end and angle crashes. Also the number of rear-end crashes increased at major four leg intersections e.g. 6x4, 6x6 etc. This thesis demonstrated the superiority of Negative Binomial regression in modeling the frequency of crashes at signalized intersections.

No description available.