| Summary: | 碩士 === 國立交通大學 === 交通運輸研究所 === 92 === Genetic fuzzy logic controller (GFLC) can overcome the drawbacks of conventional fuzzy logic controller (FLC) which has to subjectively set the logic rules and membership functions. GFLC has been successfully applied to an isolated intersection signal control, but no related study has been found in the coordinated signal control for consecutive intersections. Thus, this study attempts to construct an adaptive genetic fuzzy logic signal controller to coordinated control the signal of consecutive intersections. Based on the principle of signal coordination, four control strategies have been developed and compared in this study, which are simultaneous, progressive, alternative and independent (two independent GFLC systems for two consecutive intersections) GFLC signal control strategies. In addition, in order to investigate the performance of GFLC, four corresponding optimal pre-timed strategies are considered, which are simultaneous, progressive, alternative and independent optimal pre-timed timing plans. A fully enumerative method is employed to determine the optimal timing plan for these four pre-timed strategies.
Two-hour traffic flow data in two consecutive intersections are assumed to evaluate and compare the performance of these four signal control strategies. The results show that the progressive GFLC signal control strategy outperforms than any other three strategies in term of total delay. In contrast, alternative GFLC performs worst. Comparing to pre-timed timing plan, corresponding GFLC strategy has produced less total delay with exception of alternative one. In the other word, the progressive GFLC strategy performs best among these eight signal control strategies.
In order to investigate the performance of these strategies in varying traffic patterns, a total of six scenarios are designed by considering three levels of traffic flows in eastward direction and westward direction, which are high-high, medium-medium, low-low, high-medium, medium-low, high-low scenarios. Also notice that the east-west direction is assumed to be the signal coordinated direction. The results show that GFLC strategies obviously perform better when east-west flow volumes are largely diverse, but perform similarly to optimal pre-timed timing plans as the traffic flows of these two directions are the same.
Finally, a field study at the signalized intersections of Zhong-Zheng/Zhong-Shan North Road and Wen-Lin/Zhong-Shan North Road in Taipei City is conducted. The results show that our four GFLC strategies can cut the total delays by 26% to 56% in comparison with the current timing plan, where the progressive GFLC strategy still outperforms then other three strategies.
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