The purpose of this thesis was to perform microsimulation analyses on intersections near Highway-Railroad Grade Crossings (HRGCs) to determine if controlling mean train speed and train speed variability would improve safety and reduce delays. This research focused on three specific areas. First, average vehicle delay was examined, and this delay was compared for seven specific train speed distributions, including existing conditions. Furthermore, each distribution was associated with train detectors that were placed at the distance the fastest train could travel during the given warning time. Second, pedestrian cutoffs were investigated. These cutoffs represented an occasion when the pedestrian phases were truncated or shortened due to railroad signal preemption. Finally, vehicle emissions were analyzed using a modal emissions model. A microscopic simulation model of the Wellborn Corridor in College Station, Texas was created using VISSIM. The model was run twenty times in each train speed distribution for each of three train lengths. Average vehicle delay was collected for three intersections, and delays were compared using the Pooled t-test with a 95% confidence interval. Comparisons were made between the distributions, and generally, distributions with higher mean train speeds were associated with lower average delay, and train length was not a significant factor. Unfortunately, pedestrian cutoffs were not specifically controlled in this project; therefore, no statistical conclusions can be made with respect to the pedestrian cutoff problem. However, example cases were devised to demonstrate how these cutoffs could be avoided. In addition, vehicle emissions were examined using the vehicle data from VISSIM as inputs for CMEM (Comprehensive Modal Emissions Model). For individual vehicles, as power (defined as the product of velocity and acceleration) increased, emissions increased. When comparing emissions from different train speed distributions, few significant differences were found. However, a scenario with no train was tested, and it was shown to have significantly higher emissions than three of the distributions with trains. Ultimately, this thesis shows that average vehicle delay and vehicle emissions could be lowered by specific train speed distributions. Also, work could be done to investigate the pedestrian cutoff problem.

The purpose of this thesis was to perform microsimulation analyses on intersections near Highway-Railroad Grade Crossings (HRGCs) to determine if controlling mean train speed and train speed variability would improve safety and reduce delays. This research focused on three specific areas. First, average vehicle delay was examined, and this delay was compared for seven specific train speed distributions, including existing conditions. Furthermore, each distribution was associated with train detectors that were placed at the distance the fastest train could travel during the given warning time. Second, pedestrian cutoffs were investigated. These cutoffs represented an occasion when the pedestrian phases were truncated or shortened due to railroad signal preemption. Finally, vehicle emissions were analyzed using a modal emissions model. A microscopic simulation model of the Wellborn Corridor in College Station, Texas was created using VISSIM. The model was run twenty times in each train speed distribution for each of three train lengths. Average vehicle delay was collected for three intersections, and delays were compared using the Pooled t-test with a 95% confidence interval. Comparisons were made between the distributions, and generally, distributions with higher mean train speeds were associated with lower average delay, and train length was not a significant factor. Unfortunately, pedestrian cutoffs were not specifically controlled in this project; therefore, no statistical conclusions can be made with respect to the pedestrian cutoff problem. However, example cases were devised to demonstrate how these cutoffs could be avoided. In addition, vehicle emissions were examined using the vehicle data from VISSIM as inputs for CMEM (Comprehensive Modal Emissions Model). For individual vehicles, as power (defined as the product of velocity and acceleration) increased, emissions increased. When comparing emissions from different train speed distributions, few significant differences were found. However, a scenario with no train was tested, and it was shown to have significantly higher emissions than three of the distributions with trains. Ultimately, this thesis shows that average vehicle delay and vehicle emissions could be lowered by specific train speed distributions. Also, work could be done to investigate the pedestrian cutoff problem.

This research develops a computer simulation method for federating an Arena© port operations model and a VISSIM© roadway network operations model. The development of this method is inspired by the High Level Architecture (HLA) standard for federating simulations, and incorporates several elements of the HLA principles into its design. The federated simulation model is then tested using a time-lag experiment to demonstrate the presence of feedback loops between federated model components wherein changes to input parameters of one model during runtime can be shown to affect the operational performance of the other model. This experiment also demonstrates how several initial transient phase and steady state operating characteristics of the federated system can be determined from the federation output data. The results indicate that the method developed in this study is capable of capturing the dynamic interaction of two models in federated simulation. It is shown that feedback loops can exist between two models in federated simulation. Most notably, the federation output shows that increased traffic volume in the roadway network model influences the accumulation of containers in the port terminal queue of the port model. The federation output also shows that increased container volume leaving the port terminal model affects both port and road truck utilization, as well as the total number of port trucks in the roadway network model. Challenges and future directions for research in federating transportation-related simulations are also presented.

All computer simulation models require some form of initialization before their outputs can be considered meaningful. Simulation models are typically initialized in a particular, often "empty" state and therefore must be "warmed-up" for an unknown amount of simulation time before reaching a "quasi-steady-state" representative of the systems' performance. The portion of the output series that is influenced by the arbitrary initialization is referred to as the initial transient and is a widely recognized problem in simulation analysis. Although several methods exist for removing the initial transient, there are no methods that perform well in all applications. This research evaluates the effectiveness of several techniques for reducing initialization bias from simulations using the commercial transportation simulation model VISSIM®. The three methods ultimately selected for evaluation are Welch's Method, the Marginal Standard Error Rule (MSER) and the Volume Balancing Method currently being used by the CORSIM model. Three model instances - a single intersection, a corridor, and a large network - were created to analyze the length of the initial transient for varying scenarios, under high and low demand scenarios. After presenting the results of each initialization method, advantages and criticisms of each are discussed as well as issues that arose during the implementation. The results for estimation of the extent of the initial transient are compared across each method and across the varying model sizes and volume levels. Based on the results of this study, Welch's Method is recommended based on is consistency and ease of implementation.

Técnicas como a harmonização da velocidade procuram gerir e controlar o tráfego com base nas condições de tráfego das rodovias em tempo real. A harmonização da velocidade utiliza limites de velocidade variáveis (L.V.V.) para fornecer aos condutores uma velocidade de operação mais apropriada, normalmente inferior ao limite de velocidade estático indicado, em resposta as condições dinâmicas das vias. O L.V.V. tem demonstrado capacidade de melhorar a mobilidade e a segurança nas rodovias. Com isso, modelos de avaliação de risco de colisão em tempo real são frequentemente adotados para quantificar os riscos de ocorrência de colisões em estudos de implantação do L.V.V. Na maioria dos estudos sobre L.V.V., modelos de probabilidade de colisão são adotados apenas para mensurar o desempenho do sistema. Estes algoritmos de controle de L.V.V. não levam em conta o risco de colisões em períodos futuros, e assim não usam impactos do L.V.V. para escolher o plano de controle com relação à segurança. No Brasil, estratégias de harmonização da velocidade não são empregadas. Como as condições de tráfego nas rodovias brasileiras não são homogêneas, e cada faixa de tráfego normalmente possui médias de velocidades, intensidades de fluxo e composições de tráfego diferentes, técnicas como o L.V.V Podem oferecer benefícios ao harmonizar as velocidades entre as faixas e assim retardar o aparecimento de congestionamentos, reduzir o número de ultrapassagens e o risco de colisões. Dessa forma, este trabalho busca avaliar a relação entre as características do tráfego e a probabilidade de ocorrer conflitos entre veículos, para assim desenvolver um modelo matemático capaz de expressar tal relação – usando como estudo de caso um trecho da rodovia BR-290/RS, situada na região metropolitana da cidade de Porto Alegre. Este modelo matemático alimenta um algoritmo L.V.V., empregado em um micro simulador de tráfego, para controlar o tráfego com o objetivo de aumentar a segurança. Resultados indicam que o modelo proposto classificou corretamente 87% dos conflitos efetivamente ocorridos em campo. Os resultados de simulação indicam que o emprego do sistema L.V.V. contribuiu significativamente para a redução da probabilidade de conflitos. Ainda, o L.V.V. aumentou as velocidades médias nos períodos de fluxo elevado, e também reduziu o desvio padrão das velocidades – oferecendo um tráfego mais homogêneo – que contribui para a redução do número de trocas de faixa e, consequentemente, para um aumento da segurança. / Techniques such as speed harmonization seek to manage and control traffic based on road traffic conditions in real time. Speed harmonization uses variable speed limits (VSL) to provide drivers with a more appropriate speed, usually below the stated static speed limit, in response to dynamic road conditions. The VSL has demonstrated its ability to improve mobility and road safety. Thus, real-time collision risk assessment models are often adopted to quantify the risk of collisions occurring in VSL implantation studies. In most VSL studies, collision probability models are utilized only to measure the system performance. These VSL control algorithms do not take into account the risk of collisions in future periods, and thus do not use the VSL impacts to choose the control plan concerning safety. In Brazil, Speed harmonization strategies are not employed yet. As the traffic conditions on Brazilian highways are not homogeneous, and each traffic range usually has different average speeds, flow intensities, and traffic compositions, VSL techniques can offer benefits by harmonizing speeds between lanes, slowing down congestion, reducing the number of overtaking and the risk of collisions.( Continue) Thus, this work seeks to evaluate the relationship between traffic characteristics and the probability of conflicts between vehicles, in order to develop a mathematical model capable of expressing such a relation - using as a case the BR-290/RS freeway, located in the Porto Alegre metropolitan area. This mathematical model will then feed a VSL algorithm, employed in a micro traffic simulator, to control traffic and increase safety. Results indicate that the proposed model correctly classified 87% of the conflicts actually occurred in the field. The simulation results indicate that the VSL contributed significantly to reducing the conflicts likelihood. Even more, the VSL increased the average speeds for high flow periods, and also reduced the standard deviation of speeds - offering a more homogeneous traffic - which contributes for reduction in the number of lane changes and, consequently, to an increase in safety.

Técnicas como a harmonização da velocidade procuram gerir e controlar o tráfego com base nas condições de tráfego das rodovias em tempo real. A harmonização da velocidade utiliza limites de velocidade variáveis (L.V.V.) para fornecer aos condutores uma velocidade de operação mais apropriada, normalmente inferior ao limite de velocidade estático indicado, em resposta as condições dinâmicas das vias. O L.V.V. tem demonstrado capacidade de melhorar a mobilidade e a segurança nas rodovias. Com isso, modelos de avaliação de risco de colisão em tempo real são frequentemente adotados para quantificar os riscos de ocorrência de colisões em estudos de implantação do L.V.V. Na maioria dos estudos sobre L.V.V., modelos de probabilidade de colisão são adotados apenas para mensurar o desempenho do sistema. Estes algoritmos de controle de L.V.V. não levam em conta o risco de colisões em períodos futuros, e assim não usam impactos do L.V.V. para escolher o plano de controle com relação à segurança. No Brasil, estratégias de harmonização da velocidade não são empregadas. Como as condições de tráfego nas rodovias brasileiras não são homogêneas, e cada faixa de tráfego normalmente possui médias de velocidades, intensidades de fluxo e composições de tráfego diferentes, técnicas como o L.V.V Podem oferecer benefícios ao harmonizar as velocidades entre as faixas e assim retardar o aparecimento de congestionamentos, reduzir o número de ultrapassagens e o risco de colisões. Dessa forma, este trabalho busca avaliar a relação entre as características do tráfego e a probabilidade de ocorrer conflitos entre veículos, para assim desenvolver um modelo matemático capaz de expressar tal relação – usando como estudo de caso um trecho da rodovia BR-290/RS, situada na região metropolitana da cidade de Porto Alegre. Este modelo matemático alimenta um algoritmo L.V.V., empregado em um micro simulador de tráfego, para controlar o tráfego com o objetivo de aumentar a segurança. Resultados indicam que o modelo proposto classificou corretamente 87% dos conflitos efetivamente ocorridos em campo. Os resultados de simulação indicam que o emprego do sistema L.V.V. contribuiu significativamente para a redução da probabilidade de conflitos. Ainda, o L.V.V. aumentou as velocidades médias nos períodos de fluxo elevado, e também reduziu o desvio padrão das velocidades – oferecendo um tráfego mais homogêneo – que contribui para a redução do número de trocas de faixa e, consequentemente, para um aumento da segurança. / Techniques such as speed harmonization seek to manage and control traffic based on road traffic conditions in real time. Speed harmonization uses variable speed limits (VSL) to provide drivers with a more appropriate speed, usually below the stated static speed limit, in response to dynamic road conditions. The VSL has demonstrated its ability to improve mobility and road safety. Thus, real-time collision risk assessment models are often adopted to quantify the risk of collisions occurring in VSL implantation studies. In most VSL studies, collision probability models are utilized only to measure the system performance. These VSL control algorithms do not take into account the risk of collisions in future periods, and thus do not use the VSL impacts to choose the control plan concerning safety. In Brazil, Speed harmonization strategies are not employed yet. As the traffic conditions on Brazilian highways are not homogeneous, and each traffic range usually has different average speeds, flow intensities, and traffic compositions, VSL techniques can offer benefits by harmonizing speeds between lanes, slowing down congestion, reducing the number of overtaking and the risk of collisions.( Continue) Thus, this work seeks to evaluate the relationship between traffic characteristics and the probability of conflicts between vehicles, in order to develop a mathematical model capable of expressing such a relation - using as a case the BR-290/RS freeway, located in the Porto Alegre metropolitan area. This mathematical model will then feed a VSL algorithm, employed in a micro traffic simulator, to control traffic and increase safety. Results indicate that the proposed model correctly classified 87% of the conflicts actually occurred in the field. The simulation results indicate that the VSL contributed significantly to reducing the conflicts likelihood. Even more, the VSL increased the average speeds for high flow periods, and also reduced the standard deviation of speeds - offering a more homogeneous traffic - which contributes for reduction in the number of lane changes and, consequently, to an increase in safety.

Bangkok is a city where the congestion levels have been a major problem for many years. In 2017, Bangkok was rated the most congested city in Asia, and the second most congested in the world. According to The Expressway Authority of Thailand (EXAT), on-ramp merging is one of the most critical problem that causes congestion on the urban expressways. EXAT have evaluated several merging control strategies through microscopic traffic simulation to find suitable strategies for implementation in real life. However, their simulation studies were all based on the assumption that all motorists strictly follow the traffic rules. This is not the actual case in Bangkok, where the drivers ignore both solid lines and striped areas, as well as utilize the shoulder lane on a regular basis. The aim of this thesis is to investigate if it is possible to include this complex driving behavior in existing microscopic simulation models. A second objective is to identify merging control strategies that can reduce the occurrence and the effects of this driving behavior in order to increase the throughput at an on-ramp area on Sirat Expressway. A model was built in VISSIM and calibrated based on data collected from video recordings. In the study, parameters that are significant for the driving behavior modeling, as well as the difficulties that arise from performing a realistic calibration of the model using video observations and model-specific constraints, are identified. From the video recordings it was discovered that the main problem causing the congestion was a result of the mainline traffic who traversed to the on-ramp. Two merging control strategies were suggested to address this problem: the installment of a center barrier, and successive merging areas. The results confirmed that both actions can improve the traffic situation in terms of reducing the individual travel time. Installing a center barrier was the most efficient option and reduced the travel time by 16.58 % on the mainline and 63.24 % at the on-ramp.

Bicycles are one of the most efficient way to travel within short-distance trips due to its relatively low maintenance and operation costs (Gao, Liu, & Feng, 2012). Besides to their efficiency, bicycles provide more flexibility for their parking and its ease of use. With the increasing transportation demand in major cities, transportation authorities will encourage to use the bicycle more. However, accommodating bicycles would require physical road geometry modifications such as introducing dedicated bicycle-lanes. Cycling appears to be a sustainable form of transportation across virous countries in Europe, as a result the authorities are planning and implementing upgrades to make the transportation system safer, convenient and sustainable which is necessary to encourage more people to use bicycles as a form of transportation. This thesis is a case study which examines current traffic conditions on a bus stop at Långholmsgatan in the city of Stockholm, Sweden and evaluates the effects of different designs for bicycles and buses. At this bus stop in Långholmsgatan, the bicycle lane is located to the right of the traffic road and to the left of the bus stop in the upstream direction. Buses need to cross the bicycle lane in order to arrive and departure the bus stop. Consequently, a conflict will also be created between bicycles and buses that are crossing the bicycle lane. In this thesis, an alternative design is evaluated in which buses and bicycles are separated from each other. However, this will result in a new conflict between bicycles and pedestrians. These two designs are evaluated in terms of travel time and delay and the analysis was done using micro-simulation software VISSIM. The study shows that the current design at the bus stop of Långholmsgatan should be preferred over the alternative design when considering travel time and delay for bicycles. If buses should be considered, the alternative design should be preferred over the current design.

This thesis seeks to estimate CO2 emissions on a portion of the U.S. 101 highway in San Luis Obispo County before and after construction of a truck only lane on the Cuesta Grade. Towards that aim, the microsimulation software, VISSIM, was used in conjunction with the Environmental Protection Agency’s emissions model, MOVES. The microsimulation model was calibrated and validated against historical and present traffic volumes obtained from Caltrans with good results using several validation measures. It was found that CO2 emissions did decrease between 1998 and 2012 (pre and post lane addition), but this effect was shown to be different for the northbound (uphill) and southbound (downhill) directions. It was shown that the truck lane in the northbound (uphill) direction had a 9.5% decrease in volume with 10.7% decrease in emissions, and the southbound (downhill) direction had a 20.3% increase in volume but 7.4% decrease in emissions. For the northbound (uphill) direction, emissions seemed to correlate more closely with volumes, while the southbound (downhill) direction was less sensitive to these changes.

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