A novel closed-loop feedback traffic signal control strategy at an isolated intersection

Based on the Instantaneous Stopped Delay (ISD), this paper proposed a novel closed-loop feedback signal control strategy, which takes the total amount of ISD (ISD Total) as input detector data for measurement frame-by-frame in traffic flow video, and realizes real-time switches of the signal status when the amount reaches the threshold, and adaptively distributes the green interval to the most needed approaches (E-W and N-S) without the regular traffic signal cycle time. At the chosen intersection, in a situation when the amount of the traffic flow in a lane changed from 400/h to 800/h, a simulated comparative study was conducted by using the proposed strategy against the Webster control strategy and three conclusions were finally reached. First, under the proposed strategy, there was an obvious cut-down of the average passing time for all cars in the lane, and when the amount of the traffic flow was at 800/h, the average passing time was only 44% of that under the traditional strategy. Second, the proposed control strategy was insensitive to control threshold, for the reason that the obtained maximum relative error of the average passing time was only 11%. Finally, there was a minor variance among multiple data of average passing time, only 0.895s when the traffic flow was at 800/h in a lane at the intersection.