LEE- Ulaştırma Mühendisliği-Yüksek Lisans

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http://hdl.handle.net/11527/19477

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Yazar "Çelikoğlu, Hilmi Berk" ile LEE- Ulaştırma Mühendisliği-Yüksek Lisans'a göz atma
  • Öge
    A game-theoretical approach for analyzing effects of combined control on freeway traffic: Case of integrated ramp metering and variable speed limiting
    (Graduate School, 2024-11-27) Ademoğlu, Muhammed ; Çelikoğlu, Hilmi Berk ; 501201426 ; Transportation Engineering
    Freeways are designed to meet high transportation demands at high service levels. According to the Highway Capacity Manual (HCM), freeways are fully access-controlled, divided roads with at least two lanes in each direction. Throughout their service life, freeways encounter both recurrent and non-recurrent congestion. Recurrent congestion, as the name suggests, occurs regularly and has predictable causes. Non-recurrent congestion, on the other hand, does not occur repeatedly in the same place or time and is not predictable. An example of non-recurrent congestion is when lanes become unusable due to an accident on the road. Recurrent congestion, on the other hand, can be exemplified by traffic congestion caused by increased demand during peak hours. Modern transportation and traffic engineering approaches aim to enhance capacity not through new investments, but by adopting Intelligent Transportation Systems (ITS), traffic management, and traffic control methods to ensure more efficient and effective use of existing capacity. Under the ITS framework, various control methods have been developed to combat highway congestion. These methods include ramp metering (RM), variable speed limits (VSL), and route guidance (RG). These control strategies aim to optimize and improve the utilization of road capacity. Ramp metering aims to control traffic flows merging with the main stream via on-ramps, by delaying these merging flows in a controlled manner, thereby maintaining the density of the main stream below a certain threshold. This approach seeks to keep average speeds high and achieve a more stable traffic flow. Another ITS system, the variable speed limit application, aims to enhance flow homogeneity by reducing the speeds of vehicles in the main stream, thus delaying or preventing congestion. In some studies, variable speed limit has been integrated with ramp metering to combine the advantages of both methods, targeting more efficient use of capacity. In this thesis, a framework for modeling, control, and analysis has been developed to investigate the effects of autonomous vehicles on traffic flow dynamics and freeway capacity. Compared to similar studies in the literature, the unique aspect of this work lies in its game theory-based comparison for evaluating traffic flow performance. Game theory is a mathematical framework used to analyze strategic interactions between individuals or groups, where each player aims to optimize their own outcomes by considering the potential actions of others. This analysis evaluates possible strategies and their outcomes to predict the most rational decisions players might make. Game theory is widely used in fields such as economics, politics, sociology, psychology, and even biology to understand and model decision-making processes. In this context, an analysis based on the game defined within the thesis has been conducted. The proposed framework was tested using microscopic simulation, based on a model developed using real network and demand data. This study examined a 5-kilometer section of the D-100 freeway in Istanbul, extending from Zincirlikuyu to Halıcıoğlu. Ramp metering and variable speed limit algorithms, commonly used in the literature, were integrated into the simulation model. In the study, the Asservissement Linéaire d'Entrée Autoroutièr (ALINEA) algorithm was used for ramp metering. ALINEA is a local ramp metering algorithm with a closed-loop structure. This algorithm was integrated into a microscopic simulation software via the Component Object Model (COM) interface of the MATrix LABoratory (MATLAB) environment and applied to three ramp metering sections. For the variable speed limit control, a commonly used algorithm from the literature was also integrated into the simulation model. Additionally, an H∞ controller-based algorithm, which applies both ramp metering and variable speed limit control in an integrated manner, was selected as the third control scenario. Along with the uncontrolled scenario, a total of four primary scenarios were evaluated in the study. In each control scenario, the percentages of autonomous and human-driven vehicles were gradually adjusted, and the effects of these percentages on traffic flow under mixed traffic conditions were analyzed. For each control method, 11 different scenarios were created by gradually increasing the percentage of autonomous vehicles, and the results were compared to those of the uncontrolled scenarios. The findings were analyzed using various performance metrics, and, finally, a new performance comparison method based on game theory was proposed within the scope of the thesis. The findings obtained from this study are organized under two main headings. The first heading focuses on traffic flow performance-based analyses. In this analysis, the scenario without control, ramp metering, variable speed limit, and the integrated control scenario based on the H∞ method were evaluated based on changes in the percentage of human-driven and autonomous vehicles in the traffic flow. The evaluation was conducted using metrics such as total vehicle throughput, total travel time, and the mass of pollutants emitted by the vehicles. For both the controlled and uncontrolled scenarios mentioned above, the critical percentages of autonomous vehicles were determined. The effectiveness of these control scenarios in mixed traffic conditions was assessed by comparing the controlled scenarios to the uncontrolled scenario. The other focus of the findings is a game theory-based analysis. In this analysis, the players were first defined, and the game was structured around two players. These players are the vehicles traveling in the main traffic flow and the vehicles entering the highway from on-ramps. In the sub-scenarios created, the four different control scenarios mentioned above were considered. In this two-player game, it was assumed that one of the players consisted entirely of human-driven vehicles. For the other player, the proportion of autonomous vehicles was gradually increased from 0% to 100%, allowing for a detailed investigation of the impact of autonomous vehicles in mixed traffic. In this context, the effect of autonomous vehicles on traffic flow was analyzed based on delay per vehicle.
  • Öge
    A multi-objective optimization framework for trade-off among pedestrian delays and vehicular emissions at signal controlled intersections
    (Graduate School, 2021-12-14) Akyol, Görkem ; Çelikoğlu, Hilmi Berk ; 501181409 ; Transportation Engineering ; Ulaştırma Mühendisliği
    Traffic congestion has numerous negative effects on urban life. Increased travel time and vehicular emissions are some of these negative effects. On one hand, the transportation sector is the leading factor in contributing to climate change air pollution based on the greenhouse gas emission of 29%. On the other hand, pedestrian traffic management requires extreme caution, especially in Central Business Districts. In classic traffic signal control applications, allocation of pedestrian green time is held at the minimum value mostly. However, in crowded intersections located in city centers, the number of pedestrians that need to be served can be excessive due to a number of reasons (gatherings, touristic, sport event, etc.). In this study, an integrated methodology for optimizing traffic signal control considering pedestrian delay and vehicular emissions is developed. VISSIM is used as the microscopic traffic simulator, the Non-dominated sorting genetic algorithm-II is adopted to solve the multi-objective optimization problem at hand, and MOVES3 is used to calculate vehicular emissions on a microscopic scale. To interfere with the traffic signal control settings, COM feature of VISSIM is used in conjunction with MATLAB. By using COM interface, one can change the signal control settings, vehicle and pedestrian inputs, routes of vehicles, and many other features that can be read and changed during simulations. To illustrate the trade-off between pedestrian delay and vehicular emissions, two objective functions are formulated. The input for these functions are obtained from VISSIM via COM interface. Since the objective functions are conflicting with each other, one tries to maximize the pedestrian green time while the other tries to maximize vehicle green time, a trade-off is observed between the objectives. In addition, a case study is conducted at Kadıköy, Istanbul to evaluate the proposed approach. Data is retrieved using camera recordings. Collected data involves the vehicle and pedestrian counts, and average crossing times of pedestrians. Calibration of the simulation model is done considering GEH statistics. After the calibration, two main scenarios are designed. The first main scenario involves a gradual change in vehicles loaded to the network. The second main scenario is produced to test the different prioritization approaches with changing vehicle demand. Three different sub-scenarios are generated in this manner. First, the sub-scenario is the situation where pedestrian movement is prioritized by giving more pedestrian time compared to vehicles. The second sub-scenario is created to achieve a balance between pedestrian and vehicle green times. The third sub-scenario is produced to prioritize vehicles over pedestrians. In the second scenario, all the signal timings are chosen from the Pareto front set acquired from the multi-objective optimization solved with MATLAB. Results acquired from simulations suggest a trade-off between pedestrian delay and vehicular emissions. In conclusion, a novel method is proposed in this study to assess through trade-off the signal control settings considering pedestrian delay and vehicular emissions. Despite the fact that an optimization problem is solved in the thesis, a unique global solution is not acquired. Because more than one objective is overlooked, multiple solutions are obtained after the optimization process. The multi-objective optimization problem is handled with a posteriori approach which enabled us to sense some intuition over the problem and its Pareto optimal solutions. By using this unique feature, scenarios are designed to test the solutions. In future research, the proposed framework can be applied to a variety of networks and traffic conditions. Safety measures can be added to the multi-objective optimization framework. 3-D Pareto fronts can be acquired for pedestrian delay, emissions, and safety in an optimization framework.
  • Öge
    Analysis of e-bike charging station locations: Case of Kadıköy, Istanbul
    (Graduate School, 2022-07-01) Garipağaoğlu, Serra ; Çelikoğlu, Hilmi Berk ; 501181412 ; Transport Engineering
    With the Industrial Revolution in the 19th century, the population of cities increased rapidly and their physical areas expanded. In the last quarter of the 19th century, the invention of the automobile and the increase in its affordability with the developing technology led to an increase in automobile ownership in the 20th century. The rapidly increasing use of fossil fuels in production and transportation has created a world far from sustainable globally. In this context, environmental movements that found a common language in the 1960s started and the concept of sustainability was put forward by the Brundtland Commission in 1987. Cities are dominant living spaces. In order to achieve global sustainability goals, cities must be sustainable. For this reason, world cities have started to work toward being sustainable cities by developing policies and action plans since the Brundtland Commission.Today, the most up-to-date and valid sustainability efforts are the C40 union on a local scale and the Paris Agreement on a global scale. C40 cities aim to reach the carbon-zero city target by 2030, while the Paris Agreement aims to keep the global average temperature rise below 2°C compared to the pre-industrial period and to reach the carbon-zero European Continent target by 2050. According to studies in 2019, 27% of the total carbon emissions in Europe originate from the transportation sector (EEA, 2021a). In addition, 72% of transportation-related emissions originate from road transportation (EEA, 2021b). In this case, it is necessary to create a sustainable transportation system to achieve sustainability goals at the urban and global scale.According to studies in 2017, 16,1% of total carbon emissions in Turkey originate from transportation. Furthermore, 93% of transportation-related emissions originate from road transportation (ÇŞB, 2017). As one of the countries that signed the Paris Agreement, Turkey needs to update its policies and increase its efforts to allocate sustainable transportation. According to studies in 2015, 28% of total carbon emissions in Istanbul originate from transportation. Moreover, 98% of transportation-related emissions originate from road transport (IMM, 2015a). It is essential that Istanbul, one of the C40 cities and the most populous city in Turkey, allocates a sustainable urban transportation system. Sustainable transportation aims to meet the need for access without harming the human and ecological values of today and the future. One of the basic principles of sustainable transportation is meeting the mobility demand with public transit, pedestrian transportation, and micromobility units by reducing the private car share in transportation. Cycling is also among the sustainable modes of transportation, and it is a unique tool that contributes to the environment, economy, and health and allows social interaction. The bicycle, invented at the beginning of the 19th century, has been one of the main actors of transportation in the historical process, then lost its popularity with the automobile and became popular again with sustainable transportation targets. Electric bicycles (e-bikes) were invented at the end of the 19th century, and with the developing battery technology, they have increased their market share in the world, especially in the 21st century. E-bikes are expected to reach 130 million by 2025 and 800 million by 2100 (Morchin and Oman, 2006a; Hung and Lim, 2020). Another factor in the popularization of E-bikes is that it is an individual vehicle that combines the advantages of automobiles and bicycles. The batteries of e-bikes can be used for up to 5 years when charged with appropriate methods. Charging the battery up to 95% after each trip is recommended to increase battery life. During the journey that will end at home, people will be able to charge their e-bikes at home. However, this situation reveals the need to charge e-bikes during trips that end in public spaces. Facility location problem is a widely studied subject in private and public sector investments. Facility locations are long-term and strategic decisions, and choosing suitable locations is extremely important. Although e-bike charging stations (EBCS) are implemented in many cities worldwide, it has not yet been discussed as a facility layout problem in the literature. The number of e-bikes in Istanbul is deficient compared to European cities, and it is not possible to conduct a study by determining the need according to the supply-demand balance. The average range of the produced e-bikes is 35 km (Morchin and Oman, 2006a) and the average trip distance with electric bicycles is 9-10 km (ÇŞB, 2021). In this case, it cannot be said that range is a primary constraint for e-bikes. For charging stations to be located in public areas, a relationship between electric bicycles and urban functions and infrastructure elements should be established. An analytical method should be adopted by determining the criteria that will affect the location selection. Since no similar study has been found in the literature for EBCS, the criteria affecting the location selection for electric vehicle charging stations (EVCS), bicycle sharing system (BSS) stations, and bicycle parking structures are examined within the scope of the study. In addition, local laws and regulations are examined and constraints are revealed. Based on these studies, criteria that will affect the determination of the locations of EBCS are determined. Within the scope of the study, the Analytical Hierarchy Process (AHP), which has the advantage of qualitative and quantitative evaluation, which is one of the Multiple-Criteria Decision Making (MCDM) methods, is used. It is aimed to determine the weights of the criteria by AHP and determine the most suitable locations by Geographic Information Systems (GIS). A total of 75 experts from Istanbul Metropolitan Municipality (IMM), academia, non-governmental organizations (NGOs), companies, Ministry of Transport and Infrastructure, and Union of Municipalities of Marmara participated in the expert survey prepared to determine the weight of the criteria that affect the determination of EBCS locations at the district scale. The analysis's prominent urban functions and infrastructure elements are rail systems, existing protected bicycle roads, parking lots, bus rapid transit (BRT), parks and green areas, and water transportation. Kadıköy district is chosen as the study area. The fact that Kadıköy is the district with the highest rate of bicycle use (EMBARQ Turkey, 2015) and that those who first accepted and started riding bicycles in the historical process were those living in Kadıköy (Ceylan, 2020) are among the factors in the selection of Kadıköy as the case area. At the same time, Kadıköy is a district with high mobility due to its location on the Anatolian side and diversity of transportation infrastructure. The presence of many functions such as residential, commercial, business centers, and universities in the district both increases the mobility within the district and causes it to attract a lot of population from outside the district. The district is also a center of attraction with its green areas, cultural functions, and variety of cafes/restaurants. It has the characteristics of a medium-sized European city with its diversity of functions, an area of 25,20 km2 (Kadıköy Municipality, 2022), and a population of 481 983 people (TÜİK, 2022). A study to be carried out in Kadıköy will also be a guide for medium-sized cities. According to the criteria determined within the scope of the study, the data of Kadıköy are created with the help of GIS. Kadıköy is examined according to criteria and weights by creating 1x1 km grids. In the analysis, C2 and C1 grids are determined as the priority application area. The common features of these areas are that they contain more than one type of public transportation and attract visitors both from within and outside the district with their functions. C2 and C1 grids with the highest scores are analyzed in more detail within the scope of the study. Since there is no study in the literature on the walking distance to EBCS, studies on other bicycle infrastructures are examined. In the literature, it has been stated that the maximum walking distance to bicycle parking structures is 100 m, but this distance can be increased if safety is increased and different functions are added. It is also stated that the walking distance for shared bikes is 300 m and a person's walking tolerance is 300 m to access bike. Within the scope of this information, a radius of 100 m as the primary service area, a radius of 200 m as a secondary service area, and a radius of 300 m as a tertiary service area are determined for EBCS. The analysis of C2 and C1 grids aims to include the high-weight criteria in the primary service area. At the same time, proximity to public buildings is taken into account to make easier the connection to the urban electricity infrastructure system. Public property areas are chosen to reduce costs and make implementation easier. In this context, a location that primarily serves the rail system, BRT, green area, parking lot, and bus functions are determined for the C2 grid. At the designated location, the station will benefit from the electrical system of the rail system and BRT, and the land is in public ownership. For the C1 grid, a location primarily serves the rail system, water transportation, green space, parking lot, and bus functions are determined. At the designated location, the station will be able to use the library's electrical system and the land is in public ownership. At the same time, it is important that the determined locations are related to the road and are visible. The study is carried out to determine the locations of EBCS, which are a bicycle infrastructure element. When the main urban functions and infrastructures are examined, it can be said that supporting these locations with other bicycle infrastructures such as bicycle sharing systems, bicycle parking structures, repair stations, and bicycle roads is essential in increasing the share of bicycle transportation. Within the scope of the study, it is aimed to determine the locations of EBCS in public spaces. In addition, EBCS should be implemented in residential parking lots, business centers, and shopping centers. Moreover, bicycle transportation should be supported with parking structures.