Optimization of stretching-segment design and signal timing in traffic control
交通控制中展宽段设计与信号配时的优化

To deal with the interaction between the stretching-segment design and signal timing, we optimize the timing warrants, the phase and the phase sequence. By the intrinsic link between the stretching-segment and the signal control, we design the stretching-segment without considering the constraint for intersection space. This design not only meets the requirements in signal control, but also ensures no overflow for the queue vehicles and minimal impact on the opposite exit-lane traffic. By using the traffic control theory and traffic flow theory, we build the computational model for the stretching-segment length. When the intersection space is constrained, the equivalent saturation flow rate is used as the warrant for the signal timing in the control strategy, if there is not interference between the straight traffic flow and the left-turn traffic flow. On the other hand, if serious interference exists between these two traffic flows, the control strategy is to optimize the phase and phase sequence. By this strategy, we build a nonlinear optimization model based on Webster theory to minimize the delay and use genetic algorithm for determining associated parameters. The proposed methods and models are simulated for validity by using the simulation software VISSIM.