Microsimulation-based analysis of pedestrian overpass case study: İstanbul Şirinevler metrobus stop

Abstract

Humanity strives to adapt its environment to its needs and desires. This effort of humanity and its developing needs have enabled it to reveal various highway structures. Overpasses, in other words, pedestrian bridges, are types of structures built from different materials to overcome different obstacles from past to present. Pedestrian bridges were first built-in order to cross the openings that are difficult to pass due to necessity, as stated in the sources. It has been attributed with different functions for different purposes in history and has preserved its importance in every period. Today, the gradual growth of cities and population growth have created different problems in big cities. New urban planning was made with the widespread use of motor vehicles. The complete separation of motor vehicles and pedestrians has created an obligation in this context. At this point, pedestrian overpasses were built to meet this need. Over time, more functions have been attributed in proportion to user needs. With the technological developments, more openings have been passed and simpler solutions have been introduced to meet the increasing demand. Pedestrian overpasses are structures built in metropolitan cities to allow pedestrians to cross wide vehicle roads, railways, tramlines, metro and metrobus roads, and streams. While creating the transition on these lines, priority was given to the built-in front of heavy areas such as schools, hospitals, city centers, and squares. Thus, vehicle and pedestrian traffic are separated from each other. Along with pedestrian overpasses, different solutions have been realized in vertical circulation in the form of stairs, escalators, elevators and ramps. With the increase in material diversity and quality, both the visual effect has been increased and the amount of comfort has been increased by creating different solutions. Pedestrian overpass plans were made out of the needs arising over time rather than being a planned structure in the cities. In fact, with the increasing traffic and pedestrian density over time, some areas needed to be re-planned and rebuilt. In this study, the old and current condition of the Şirinevler overpass with the alternative overpass solution, which is one of the overpasses with the highest pedestrian density in the city of Istanbul and has been re-planned over the years, has been evaluated. The main reason why the Şirinevler overpass is handled is that it has been the subject of many news in the media over the years, as it is insufficient in the face of increasing passenger demand. Thus, as a result of the analysis of this inadequate bridge, the parameters that an overpass should have and that should be considered during its planning were revealed. In particular, the Şirinevler overpass, which is integrated with the Aksaray-Atatürk Airport Metro and Metrobus line in terms of the rail system, has a special location in a metropolitan way like Istanbul, as it is integrated with bus and minibus lines in terms of rubber-wheeled transportation. Due to the importance and special location of this overpass, it is necessary to analyze the traffic effect and therefore the effect of pedestrian density on the bridge. PTV VISSIM is a micro-scale multi-modal traffic flow simulation widely used to evaluate traffic conditions. PTV VISSIM is a software that allows the designing of efficient traffic management strategies and testing different structures to achieve a sustainable city logistics and sustainable urban traffic system. One of the most necessary steps for traffic planning; is the evaluation of various traffic management scenarios and taking optimization measures before implementation in order to choose the best alternative. The aim of this study is to design the simulation model of the Şirinevler overpass using the PTV VISSIM microsimulation program in context, and as a result, to compare its old and current condition by presenting a new alternative solution. In line with the results obtained, the parameters that the overpass structures should have according to the location and traffic density were evaluated. Within the scope of the study, a simulation model was created with PTV VISSIM using the minimum parameters that the pedestrian overpass should have and the pedestrian data counted in the Şirinevler overpass in 2016, and different analyzes were made by adapting the same modeling to the current condition of the Şirinevler overpass. The analyzes that emerged through the results obtained with PTV VISSIM were summarized as Network Performance, Pedestrian Density, Speed, Travel Times, and Area / Ramp Performance Measures. As a result of this study, it is aimed to present improvement suggestions that can be a reference for similar stops on the Metrobus line in line with the data obtained and alternative solution suggestions.