Fatores contribuintes de acidentes ocorridos em interseções de três ramos em Portugal: elementos da consistência geométrica

Este artigo apresenta um estudo sobre os acidentes ocorridos em interseções de três ramos inseridas em estradas nacionais da região norte portuguesa (2008-2010). O estudo é feito através do desenvolvimento de modelos que permitem a avaliação do impacto da consistência geométrica do traçado sobre a ocorrência de acidentes. Foram analisados os parâmetros: frequência de acidentes, tráfego e características geométricas de 177 interseções (531 observações). O processo foi baseado em equações de estimação generalizadas, com estrutura de correlação predominante autorregressiva. O estudo confirma a crescente necessidade de ser incorporado na modelação de acidentes o efeito da variação das condições gerais do traçado das estradas.Fundação para a Ciência e a Tecnologia (FCT), Portugal, através do financiamento da bolsa de doutoramento SFRH/BD/62458/2009 e do projeto UI 4047 – 2014: PEst-OE/ECI/UI4047/2014

Collision prediction models with longitudinal data: an analysis of contributing factors in collision frequency in road segments in Portugal

In spite of the strategic importance of the national Portuguese road network, there are no recent studies concerned with either the identification of contributory factors to road collisions or collision prediction models (CPMs) for this type of roadway. This study presents an initial contribution to this problem by focusing on the national roads NR-14, NR-101 and NR-206, which are located in Portugalâ s northern region. This study analyzed the collisions frequencies, average annual daily traffic (AADT) and geometric characteristics of 88 two-lane road segments through the analysis of the impact of different database structures in time and space. The selected segments were 200-m-long and did not cross through urbanized areas. Data regarding the annual traffic collision frequency and the AADT were available from 1999 to 2010. The GEE procedure was applied to ten distinctive databases formed by grouping the original data in time and space. The results show that the different observations within each road segment present mostly an exchangeable correlation structure type. This paper also analyses the impact of the sample size on the modelâ s capability of identifying the contributing factors to collision frequencies, therefore must work with segments homogeneous greatest possible. The major contributing factors identified for the two-lane highways studied were the traffic volume (AADT), lane width, horizontal sinuosity, vertical sinuosity, density of access points, and density of pedestrian crossings. Acceptable CPM was identified for the highways considered, which estimated the total number of collisions for 400-m-long segments for a cumulative period of six years

Use of Bond Issues To Capture Financial Surplus Generated For The Private Sector By Public Investments In Transport Projects: Brazilian Legislation

It is widely known that the capitals market is a major source of permanent financial resources for the economy because of the connection it establishes between agents with savings capacity (investors) and those in need of long term financial resources (finance borrowers). That being so, this paper presents a study on the possibility of capturing the financial surplus generated for the Private sector by public investments in transport projects using financing instruments, specifically, bonds. Such a study is needed to provide supporting information for new investments in transport projects given the scarcity of financial resources in a considerable number of Latin American countries. The analysis undertaken considers the Brazilian Capitals Market as a case study and accordingly the concepts used in it are presented in the perspective of Brazilian legislation.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Use of Bond Issues To Capture Financial Surplus Generated For The Private Sector By Public Investments In Transport Projects: Brazilian Legislation

It is widely known that the capitals market is a major source of permanent financial resources for the economy because of the connection it establishes between agents with savings capacity (investors) and those in need of long term financial resources (finance borrowers). That being so, this paper presents a study on the possibility of capturing the financial surplus generated for the Private sector by public investments in transport projects using financing instruments, specifically, bonds. Such a study is needed to provide supporting information for new investments in transport projects given the scarcity of financial resources in a considerable number of Latin American countries. The analysis undertaken considers the Brazilian Capitals Market as a case study and accordingly the concepts used in it are presented in the perspective of Brazilian legislation.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Financiamento de projetos de transportes no Brasil : análise crítica dos mecanismos da economia financeira no uso da captura do excedente econômico

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2009.A demanda da sociedade brasileira por transportes tem apresentado crescimento constante, não comportado pela oferta desse serviço, o que impede o crescimento econômico desejado. Por outra parte, a poupança do setor público é insuficiente para financiar os investimentos requeridos. A insuficiência de poupança do setor público atinge não apenas o Brasil, mas também muitos outros países em desenvolvimento. Em vista disto, muitos estudiosos sugerem a participação da iniciativa privada nas inversões públicas em projetos de transportes. Estudos mostram que a implementação de projetos de transportes acarreta excedente econômico para o setor privado. Esta dissertação explora a possibilidade do financiamento de projetos de transportes e, principalmente, a possibilidade do excedente econômico privado esperado promovido por investimentos públicos ser carreado para o financiamento de projetos. Logo, para solucionar o problema identificado, foram estudados os elementos da literatura econômica que podem ser utilizados para capturar parte do excedente econômico do setor privado. Sugere-se então, uma estrutura esquemática para financiamento de infraestrutura de transportes, utilizando os diversos elementos analisados. Sendo assim, foram identificados, como passíveis de serem utilizados na captura do excedente econômico, mecanismos da economia financeira (tributos, títulos públicos e securitização) e também duas modalidades de financiamento introduzidas no Brasil nas últimas décadas, o Project Finance e as Parcerias Público-Privada. Conclui-se que a questão que afeta a escolha do elemento de captura do excedente econômico é se o investimento com os recursos captados será feito imediatamente ou no futuro. Se a decisão for pelo investimento imediato, então, os formatos mais apropriados para capturar o excedente são: o Project Finance e a Parceria Público-Privada. No entanto, se a decisão for por investimentos futuros, os mecanismos da economia financeira podem ser utilizados na captura, sendo eles: os tributos, os títulos públicos e a securitização. _________________________________________________________________________________________________ ABSTRACTEven though the Brazilian society's demand for transportation has steadily grown throughout the years, the services offered do not meet that demand. This stops the desired economic growth from being achieved. Furthermore, the public sector's savings alone are not enough to fund the required investments. Such insufficiency is rather common among developing countries. In view of that, many scholars suggest that the private sector take part in public investments in transportation projects. Moreover, studies have shown that implementing transportation projects cause economic surplus for the private sector. This paper explores the possibility of funding transportation projects and achieving the desired economic surplus for the private sector, which can be promoted by public investments, to be used for funding projects. Therefore, in order to solve that problem, we studied elements from the Economics Literature that may be used to capture part of the economic surplus from the private sector. We present a schematic structure for funding transportation infrastructure, making use of the different elements that were analyzed. Accordingly, we identified possible elements that can be used to capture economic surplus, which include mechanisms of financial economics (taxes, public securities and securitization) and two modes of financing introduced in Brazil in the last two decades, Project Finance and Public-Private partnerships. We concluded that the question which affects the choice of the element for capturing the economic surplus is whether the investment of the captured resources will take place immediately or in the future. If it happens immediately, the most appropriate forms of capturing the economic surplus are the Project Finance and the Public-Private partnership. However, if the investment happens in the future, mechanisms of financial economics, such as taxes, public securities and securitization may be used to capture resources

Portuguese two-lane highways: modelling crash frequencies for different temporal and spatial aggregation of crash data

The identification of contributory factors to crash frequencies observed in different highway facilities can aid transportation and traffic management agencies to improve road traffic safety. In spite of the strategic importance of the national Portuguese road network, there are no recent studies concerned with either the identification of contributory factors to road crashes or crash prediction models (CPMs) for this type of roadway. This study presents an initial contribution to this problem by focusing on the national roads NR-14, NR-101 and NR-206, which are located in Portugalâ s northern region. They are two-lane single carriageway rural roads. This study analyzed the crash frequencies, average annual daily traffic (AADT) and geometric characteristics of 88 two-lane road segments. The selected segments were 200-m-long and did not cross through urbanized areas. The fixed length of 200 meters corresponds to the road length used in Portugal to define a critical point. Data regarding the annual crash frequency and the AADT were available from 1999 to 2010. Due to the high number of zero-crash records in the initial database, the data were explored to identify the best statistical modeling approach to be adopted. The GEE procedure was applied to 10 distinctive databases formed by grouping the original data in time and space. The results show that the different observations within each road segment present an exchangeable correlation structure type. This paper also analyses the impact of the sample size on the modelâ s capability of identifying the contributing factors to crash frequencies. The major contributing factors identified for the two-lane highways studied were the traffic volume (expressed in AADT), lane width, vertical sinuosity, and density of access points. Acceptable CPM was identified for the highways considered, which estimated the total number of crashes for 400-m-long segments for a cumulative period of two years