Abstract: An original optimal algorithm was developed for controlling the signal in isolated intersection. The time length of the next cycle was obtained by fuzzy reasoning, based on the effective prediction of the arriving vehicles in every direction and every line in the next cycle. The multiobjective optimal model was built to get the least time delay and the most traffic flow capacity. The objective function was optimized by sortingGA and the split of each phase was obtained. The time length was divided into each phase according to the split. So the optimal signal time assignment was completed. By the computer simulation, the result shows that the algorithm is effective.

Key words: multiobjective, sortingGA , isolated intersection