La presente tesis se basa en el análisis del flujo vehicular, presente en el óvalo La Curva, ubicada en el distrito de Chorrillos, Departamento de Lima-Perú. El proyecto evalúa las condiciones de servicio, diseño del óvalo y el tráfico vehicular. Esta evaluación es realizada mediante un modelo microscópico que es simulado en el software Vissim 9.0. La construcción del modelo consiste en 4 fases. La primera, trata del análisis previo, que abarca desde la recolección de datos hasta el procesamiento en gabinete. Por un lado, la toma de medidas geométricas se realizó en un día de menor volumen vehicular. Por otro lado, el aforo vehicular y peatonal se realizó en un día típico. La segunda fase consiste en el modelamiento inicial, que busca trasladar el diseño geométrico actual al Vissim para proceder con la microsimulación. Asimismo, se realizaron múltiples corridas hasta lograr la optimización del modelo, previo precalentamiento y calibración del mismo. La tercera fase analiza el diseño propuesto en base a los parámetros de eficiencia vehicular, como son el tiempo de viaje (demoras), la longitud de cola y el nivel de servicio. La propuesta busca optimizar el sistema de semaforización, actualmente existente e inoperativa, y un cambio de nivel en una de las avenidas que concurre mayor cantidad flujo vehicular. En la última fase se busca evaluar y comparar los resultados, tanto de la situación actual como de la alternativa propuesta. Finalmente, los parámetros que presenten mejoras en su servicio serán determinantes para reducir el problema de congestión vehicular. / This thesis is based on the analysis of vehicle flow, present in the La Curva oval, located in the district of Chorrillos, Department of Lima-Peru. The project evaluates service conditions, oval design and vehicular traffic. This evaluation is done through a microscopic model that is simulated in Vissim 9.0 software. The construction of the model consists of 4 phases. The first one deals with the previous analysis, which ranges from data collection to cabinet processing. On the one hand, the geometric measurements were taken on a day with less vehicular volume. On the other hand, vehicular and pedestrian traffic was performed on a typical day. The second phase consists of the initial modeling, which seeks to transfer the current geometric design to the Vissim to proceed with the microsimulation. Likewise, multiple runs were performed until the model was optimized, after preheating and calibrating it. The third phase analyzes the proposed design based on vehicle efficiency parameters, such as travel time (delays), tail length and service level. The proposal seeks to optimize the traffic signaling system, currently existing and inoperative, and a change of level in one of the avenues that has the greatest amount of traffic flow. In the last phase, the aim is to evaluate and compare the results, both of the current situation and of the proposed alternative. Finally, the parameters that present improvements in their service will be decisive to reduce the problem of vehicular congestion. / Tesis

<p>Two executable simulation models for answering policy questions were designed and implemented. The first for a flood management case, and the second for a disease transmission case that is currently underway. The flood simulation model differs from earlier natural disaster simulation models in several respects. It represents explicitly the geographical location and the economic strength of each household. It is also equipped with a graphical user interface, making it possible to design policies interactively, and to test their outcomes. If policy options are compared, the simulation results can automatically be transformed into decision trees. The flood simulation model shows that a micro-level representation makes it possible to investigate the distributional effects of policy changes. Novel features of the disease transmission model include the use of (anonymized) data representing nine million individuals, the inclusion of important parts of the contact patterns, and the explicit representation of places. The disease transmission model shows that the incorporation of social structure allows for a more realistic representation of disease spread than do models that assume homogenous mixing. Using this model, it is possible to conduct experiments of significant policy relevance, such as investigating the initial growth of an epidemic on a real-world network. Together, the two cases demonstrate the usefulness of a spatially explicit micro-level representation for policy simulation models in the area of disaster management.</p>

The paper describes the content of the project “Tax-/Transfer-Reform and Fiscal Responsibility: Pathways to a Sustainable Fiscal Policy in Georgia”, which is supported for the period Fall 2005 to Spring 2008 by the VolkswagenStiftung. Within the project a knowledgetransfer is organized, concentrating on state theory, tax and transfer reform, revenue sharing as well as fiscal equalization. A short overview on the current situation in Georgia is presented. Then the main project components – tax reform, tax revenue estimation and microsimulation – are briefly discussed.

Two executable simulation models for answering policy questions were designed and implemented. The first for a flood management case, and the second for a disease transmission case that is currently underway. The flood simulation model differs from earlier natural disaster simulation models in several respects. It represents explicitly the geographical location and the economic strength of each household. It is also equipped with a graphical user interface, making it possible to design policies interactively, and to test their outcomes. If policy options are compared, the simulation results can automatically be transformed into decision trees. The flood simulation model shows that a micro-level representation makes it possible to investigate the distributional effects of policy changes. Novel features of the disease transmission model include the use of (anonymized) data representing nine million individuals, the inclusion of important parts of the contact patterns, and the explicit representation of places. The disease transmission model shows that the incorporation of social structure allows for a more realistic representation of disease spread than do models that assume homogenous mixing. Using this model, it is possible to conduct experiments of significant policy relevance, such as investigating the initial growth of an epidemic on a real-world network. Together, the two cases demonstrate the usefulness of a spatially explicit micro-level representation for policy simulation models in the area of disaster management.

Variable Speed Limit Sign (VSLS) systems enable transportation managers to dynamically change the posted speed limit in response to prevailing traffic and/or weather conditions. VSLS are thought to improve safety and reduce driver stress while improving traffic flow and travel times. Although VSLS have been implemented in a limited number of jurisdictions throughout the world, there is currently very limited documentation describing the quantitative safety and operational impacts. The impacts that have been reported are primarily from systems in Europe, and may not be directly transferable to other jurisdictions, such as North America. Furthermore, although a number of modelling studies have been performed to date that quantify the impacts of VSLS, the VSLS control strategies are often too complex or based on unrealistic assumptions and therefore cannot be directly applied for practical applications. Consequently, a need exists for an evaluation framework that quantifies the safety and traffic performance impacts of comprehensive VSLS control strategies suitable for practical applications in North America. This paper presents the results of an evaluation of a candidate VSLS system for an urban freeway in Toronto, Canada. The evaluation was conducted using a microscopic simulation model (i. e. a model that predicts individual vehicle movements) combined with a categorical crash potential model for estimating safety impacts. <br /><br /> The objectives of this thesis are: 1) to validate a real-time crash prediction model for a candidate section of freeway; 2) to develop a candidate VSLS control algorithm with potential for practical applications; 3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and 4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm. <br /><br /> The analysis of the VSLS impacts under varying levels of traffic congestion indicated that the candidate control strategy was able to provide large safety benefits without a significant travel time penalty, but only for a limited range of traffic conditions. The tested algorithm was found to be insufficiently robust to operate effectively over a wide range of traffic conditions. However, by modifying parameters of the control algorithm, preliminary analysis identified potential improvements in the performance of the VSLS. The modified control strategy resulted in less overall travel time penalty without an adverse impact on the safety benefits. It is anticipated that further modifications to the VSLS control strategy could result in a VSLS that is able to operate over a wide range of traffic conditions and provide more consistent safety and travel time benefits, and it is recommended that the framework used in this study is an effective tool for optimizing the algorithm structure and parameter values.

Variable Speed Limit Sign (VSLS) systems enable transportation managers to dynamically change the posted speed limit in response to prevailing traffic and/or weather conditions. VSLS are thought to improve safety and reduce driver stress while improving traffic flow and travel times. Although VSLS have been implemented in a limited number of jurisdictions throughout the world, there is currently very limited documentation describing the quantitative safety and operational impacts. The impacts that have been reported are primarily from systems in Europe, and may not be directly transferable to other jurisdictions, such as North America. Furthermore, although a number of modelling studies have been performed to date that quantify the impacts of VSLS, the VSLS control strategies are often too complex or based on unrealistic assumptions and therefore cannot be directly applied for practical applications. Consequently, a need exists for an evaluation framework that quantifies the safety and traffic performance impacts of comprehensive VSLS control strategies suitable for practical applications in North America. This paper presents the results of an evaluation of a candidate VSLS system for an urban freeway in Toronto, Canada. The evaluation was conducted using a microscopic simulation model (i. e. a model that predicts individual vehicle movements) combined with a categorical crash potential model for estimating safety impacts. <br /><br /> The objectives of this thesis are: 1) to validate a real-time crash prediction model for a candidate section of freeway; 2) to develop a candidate VSLS control algorithm with potential for practical applications; 3) to evaluate the performance of the VSLS control strategy for a range of traffic conditions in terms of safety and travel time; and 4) to test the sensitivity of the VSLS impact results to modifications of the control algorithm. <br /><br /> The analysis of the VSLS impacts under varying levels of traffic congestion indicated that the candidate control strategy was able to provide large safety benefits without a significant travel time penalty, but only for a limited range of traffic conditions. The tested algorithm was found to be insufficiently robust to operate effectively over a wide range of traffic conditions. However, by modifying parameters of the control algorithm, preliminary analysis identified potential improvements in the performance of the VSLS. The modified control strategy resulted in less overall travel time penalty without an adverse impact on the safety benefits. It is anticipated that further modifications to the VSLS control strategy could result in a VSLS that is able to operate over a wide range of traffic conditions and provide more consistent safety and travel time benefits, and it is recommended that the framework used in this study is an effective tool for optimizing the algorithm structure and parameter values.

A study was done to explore the suitability of intersection and arterial collision prediction models based on traffic conflicts, generated using the Paramics microsimulation suite and the Surrogate Safety Assessment Model (SSAM). A linear regression model and a generalized linear model with a negative binomial error structure were explored to correlate conflicts to crash rates, as well as the conflict-based models suggested by SSAM. The model predictions were compared to volume-based predictions and historical data from Toronto, Ontario, Canada. The volume- based predictions were calculated using a negative binomial generalized linear model, fitted to the same arterial and intersection sets used to fit the conflict-based models. The results show the predictions generated by a conflict-based model were comparable for intersections, but poor for arterials.

A study was done to explore the suitability of intersection and arterial collision prediction models based on traffic conflicts, generated using the Paramics microsimulation suite and the Surrogate Safety Assessment Model (SSAM). A linear regression model and a generalized linear model with a negative binomial error structure were explored to correlate conflicts to crash rates, as well as the conflict-based models suggested by SSAM. The model predictions were compared to volume-based predictions and historical data from Toronto, Ontario, Canada. The volume- based predictions were calculated using a negative binomial generalized linear model, fitted to the same arterial and intersection sets used to fit the conflict-based models. The results show the predictions generated by a conflict-based model were comparable for intersections, but poor for arterials.

The purpose of this research is to develop an intersection safety evaluation tool that is capable of assisting designers and planners in the assessment of alternative intersection designs. A conflict exposure model utilizing design hour volumes, intersection configuration and traffic control measures is proposed to achieve this goal. This approach makes use of data typically available for preliminary intersection design. The research goes beyond existing safety performance models which only examine non-directional average daily traffic (ADT) or practices which only account for the geometric and lane configuration of an intersection, such as conflict point analysis. Conflict prediction models are developed for left-turn angle, right-turn, rear end and sideswipe crashes. These models were developed through the analysis of over 1000 simulation scenarios evaluating a full range of approach and turning volumes, lane configurations and traffic control strategies. The quantifiable metrics provided can be used to inform and improve alternative intersection selection processes by differentiating between alternatives based on a surrogate safety performance. This research may be used in screening of intersection alternatives to select the most beneficial design based on objective safety performance metrics.

The calibration of microscopic traffic simulation models is an area of intense study; however, additional research is needed into how to select which parameters to calibrate. In this project a procedure was designed to eliminate the parameters unnecessary for calibration and select those which should be examined for a VISSIM model. The proposed iterative procedure consists of four phases: initial parameter selection, measures of effectiveness selection, Monte Carlo experiment, and sensitivity analysis and parameter elimination. The goal of the procedure is to experimentally determine which parameters have an effect on the selected measures of effectiveness and which do not. This is accomplished through the use of randomly generated parameter sets and subsequent analysis of the generated results. The second phase of the project involves a case study on implementing the proposed procedure on an existing VISSIM model of Cobb Parkway in Atlanta, Georgia. Each phase of the procedure is described in detail and justifications for each parameter selection or elimination are explained. For the case study the model is considered under both full traffic volumes and a reduced volume set representative of uncongested conditions.