Study of Green Wave in Virtual-Traffic-Light Environment through VANETs

• Main Authors: Tsung-Yi Shen, 沈宗億
• Other Authors: Li-Der Chou
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/40919956078178629913

碩士 === 國立中央大學 === 資訊工程學系在職專班 === 101 === Urban traffic congestion causes energy consumption and emissions. However, traditional traffic light is fixed time to change between green and red light. If traffic lights can dynamic change by traffic flow, drivers can go through a series of traffic lights with dynamic speed guidance over several intersections. Therefore, traffic management plays an important role in saving energy and improving vehicle speed. This study focuses on virtual traffic light and applies VANETs to support dynamic speed guidance to the drivers. Based on the speed information, we can achieve the goal of Green Wave so that energy consumption and emission reduction are minimized. Detailed are discussed the algorithm of green wave speed guidance and simulate in Taipei city. This study develops a green wave speed guidance strategy for virtual traffic light. As a traditional green wave speed guidance, any vehicle travels along with fixed speed. However, in the process of operation, the optimal speed advice to vehicle should take into consideration the current traffic conditions, road grade, etc. In this study, we presented an adjustable speed strategy based on a bi-directional intersection. According to traffic flow and the type of vehicles in the intersection decide dynamic speed guidance. Using VTL with V2V communication generates traffic signal “online” by vehicles. The dynamic speed control in virtual traffic light guides vehicle on the best running speed to go through serial intersections without stopping. Thus, green wave coordinated control reduces stop-and-go traffic and control signal to achieves real-time traffic smooth. As a case of study, the main road in Taipei is taken for simulation and evaluation in virtual traffic light. The simulation results compared with fixed signal show that, the performance of vehicle speed increased by about 47.2%. On the other hand, the improvement of throughput-to-volume increased by about 46%. As for the energy savings for vehicles with green wave speed guidance are found to be 39.1%.