Traffic behavior in the on-ramp system with signal controlling

In this paper, we investigate the on-ramp system on the highway using cellular automaton traffic model. Different from previous work, we introduce traffic signal to control the vehicle flows on the main road and the on-ramp. A method of signal controlling is presented, and the update rule in special road is given in detail according to the stimulation role of signal to the drivers. The simulation results show that, the phase diagram of on-ramp system is divided into three regions. The currents of the on-ramp system are discussed. Under the control role of traffic signal, the vehicle flows of the main road and the on-ramp can become orderly. The capacity of the system may keep a maximum value. In addition, the drastic velocity fluctuation is discussed near the on-ramp. A dangerous condition in Jiang et al. [Phys. Rev. E 66 (2002) 036104] can be effectively avoided.