Two-Stage Fuzzy Logic Controller Based on Adjustable Phase Sequence for Urban Traffic Intersection

On the basis of research on fuzzy traffic control algorithm for a single intersection, we present a new adjustable multi-phase sequence fuzzy control algorithm. By this method, not only the traffic flow of every phase is considered, but also the green time and red time. Base on this algorithm, a two-stage fuzzy control system which consist of the green time delay module and phase selection module is designed. The first stage chooses a candidate of the green light phase which has the highest emergency degree among all red light phases. The second stage judges to continue to delay or convert green light phase according to the length of the vehicle queue at the current green light phase and the candidate. Computer simulation shows that the new type of fuzzy control algorithm possesses flexible phase combination with little delay, it can solve the imbalance of traffic flow very well at the intersection.