Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

Modeling Delays Caused by Traffic Congestion with Speed Management
The growth in urban traffic congestion has become a serious problem in all large metropolitan areas. In recent years the result of the increasing car ownership, the continuous increase of the vehicle use corresponding to the non development of road infrastructure to meet the increasing user demand is considered as a major problem. The adverse effects of traffic congestion are: increased delays, reduced traffic flow speed and the increase of fuel consumption. The problems of main transportation lines related to the traffic which arises as a result of rapid increase in population density and urbanization are more prominent than the infrastructural problems. The traffic flow at the main arterials, which transports various traffic types and densities to the engineering structures such as bridges and tunnels, should be kept and controlled under certain values. The purpose of this study is to prpose a model for reducing traffic congestion on structures such as bridges and tunnels, as a part of a major highway network carrying dense traffic within the city's transport infrastructure, by speed management based on speed control. In other words, the objective of this study is to investigate the effect of speed ​​management, percent of heavy vehicles, the distance between on and off-ramps, number of lanes and lane widths, geometric improvement and ramp metering on delays occurring in traffic leading to such major structures as bridges and tunnels.
To reach the aim of the study, the collected field data were used to develop mathematical models to explain how traffic delay is related to the variables mentioned above. The study shwoed that the optimom speed is 65 km/hours. The aplayying of speed maagement by this speed value would resaulted in 18% decreasing in delays, for average speed was increased by 36% according to the current situation. İn addition, some of geometric improvements (like lane addition, decreasing of double queuing at On-Ramps to one before merging) were proposed. The analysis showed that geometric improvements were highly effective on network performance that resulted rising by %32 in average speed and reduction by 49% for delays. The impact of heavy vehicle percent and lane width on traffic delays were also studied. For lane width has negative effect on total delay while the heavy vehicle percent was positive. In addition the parameters that mentioned above, ramp metering and Automatic Pass System (APS) were tested. For ramp metering optimum cycle time were computed. Finally, the distance between on & off-ramps were tested by VİSSIM. The results identified that 600 meters in practice, the ideal is the 900 meters. The sixth chapter includes possible areas of the application of the obtained results and the suggested improvements for future studies.

Keywords: Traffic Congestion, Delay, Speed ​​Management, Simulation.