The research presented in this thesis attempts to investigate the impact of detector failure frequency and failure duration on the accuracy of loop detector speed, flow, and density measurements using a Monte Carlo simulation approach. The inputs to the model are the frequency of failures and failure duration. Several regression models were developed to relate loop detector accuracy to detector failure data. The results showed that the models were consistent and similar for the same location with an R square that ranged between 86% and 94% for all models and in comparing two locations, the differences between the regression models were minor except for the flow model errors, the location had the same trend but the magnitude of the flow RMSE increased by 7.5 to 15%. The second part of the research effort attempts to quantify the impact of inclement weather (precipitation and visibility) on traffic stream free-flow speeds along freeway sections. The analysis is conducted using weather (precipitation and visibility) and loop detector data (speed) obtained from Baltimore, Minneapolis/St. Paul, and Seattle, US. The results demonstrate that visibility alone has a minimum impact on free-flow speed with reductions in the range of 1 to 3%. These reductions only appear as the visibility level falls below 1.2 km. The study demonstrates that the impact of snow is more significant than that of rain for similar intensity levels. Reductions caused by rain are in the neighborhood of 2 to 5% depending on the precipitation intensity while reductions caused by snow are in the neighborhood of 6 to 20%. With regards to freezing rain, higher reductions in free-flow speed were observed when compared to rain and snow. Specifically, the free-flow speed was reduced by 14% at the onset of freezing rain precipitation with a maximum decrease of 27% at freezing rain intensity of about 0.53 cm/h for Baltimore and as the case of Seattle the reduction was found to be constant with 31%. Finally, the paper derives free-flow speed reduction factors that vary as a function of the precipitation type and intensity level. These reduction factors can be incorporated within the Highway Capacity Manual's procedures. / Master of Science

nÃo hà / Implementation of Basel, whose goal is to strengthen the soundness and stability of the financial system is essentially based on the stipulation of a minimum capital ratio. Although a higher ratio of capital increase costs for institutions, it is common to note that many of these institutions maintain a capital ratio above the regulatory minimum. Thus, this work is meant to examine how Brazilian banks adjust their capital ratios. Secondarily aims to assess the determinants of the speed of adjustment, emphasizing the importance of the variables of rating. For this purpose, we use the methodology employed by Berger et al. (2008) using a model in three stages. We used quarterly data from 2005 to 2010 refer to 57 banks. As a result it was found that if the bank has traded lower its rate of capital, the larger the size the greater the bankâs capital held, which is contrary to results obtained in the literature, and the proxies to measure the rating institutions were non-significant. / A implementaÃÃo do Acordo de BasilÃia, cujo objetivo à o de reforÃar a solidez e a estabilidade do sistema financeiro, baseia-se essencialmente na estipulaÃÃo de uma razÃo mÃnima de capital. Muito embora uma maior razÃo de capital aumente os custos para as instituiÃÃes, à comum verificar-se que muitas dessas instituiÃÃes mantÃm uma razÃo acima do mÃnimo regulatÃrio. Neste sentido, este trabalho tem como principal objetivo analisar como os bancos brasileiros ajustam suas razÃes de capital. De modo secundÃrio, pretende-se avaliar os determinantes da velocidade de ajuste, ressaltando-se a importÃncia das variÃveis de rating. Para tanto, utilizase a metodologia empregada por Berger et al. (2008) que utiliza um modelo em trÃs estÃgios. Foram utilizados dados trimestrais de 2005 a 2010 referentes a 57 bancos. Como resultado obteve-se que, se o banco possui capital aberto menor serà a sua razÃo de capital, quanto maior o tamanho do banco maior serà o capital mantido, sendo este contrÃrio a resultados obtidos na literatura, e as proxys para mensurar o rating das instituiÃÃes mostraram-se nÃo significante.