Optimal control of arterial signals is critical for the effective operation of urban road network. With the goal of providing reasonable allocation of bidirectional green time while maximizing general bidirectional traffic progression along the arterial, this paper develops an improved general bidirectional coordinated progression model for arterial based on Maxband model. In the model, a proportional coefficient of bidirectional bandwidth demands is introduced and calibrated by adopting average link queue occupancy. The calibration method takes full account of actual traffic volume and capacity of each link, which helps to provide optimal control performance. Additionally,new constraints are added into the model and enable the model with two features: it can automatically select two-way or one-way progression, and the involved intersection unit can be either one-phase-one-approach or bidirectional symmetric release mode. The results of extensive simulation studies indicate that the improved model outperforms existing methods, markedly increasing the utilization of available bidirectional green time. Optimal control of arterial signals is critical for the effective operation of urban road network. With the goal of providing reasonable allocation of bidirectional green time while maximizing general bidirectional traffic progression along the arterial, this paper develops an improved general bidirectional coordinated progression model for arterial based on Maxband model. In the model, a proportional coefficient of bidirectional bandwidth demands is introduced and calibrated by employing average link queue occupancy. The calibration method takes full account of actual traffic volume and capacity of each link, which helps to provide optimal control performance. Additionally, new constraints are added into the model and enable the model with two features: it can automatically select two-way or one-way progression, and the involved intersection unit can be either one-phase-one-approach or bidirectional symmetric release mode The results of extensive simulation studies indicate that the im proved model outperforms existing methods, markedly increasing the utilization of available bidirectional green time.