Crosswalks are a kind of important pedestrian crossing facility． It is proper to implement the simultaneous signalization at integrated crosswalks and the separate signalization at split crosswalks． Regarding isolated split midblock crosswalks，a method to calculate the maximum pedestrian-crossing time is proposed according to the time-space diagram of pedestrian movements． Regarding closely-spaced split midblock crosswalks along an arterial，a coordinated signal timing optimization model is constructed by means of the integer nonlinear programming method according to the time-space diagram of vehicular movements． In the constructed model，the maximum of the maximum pedestrian-crossing time in any crosswalk and in any movement direction is minimized without any negative effect on the two-way green waves for vehicular movements． Case studies indicate that the constructed model is of practical value and can be widely applied．