都市地區於設計連鎖號誌系統時，需將號誌化路口實施群組劃分之工作，但往往 兩相鄰群組間之最佳週期長度均無法相同，而為增進整體系統之控制績效，應將所有相鄰群 組制定最佳之連鎖時差。本研究提出「續進可能值」(progression possibility)之概念以 作為衡量群組間最佳時差之基準，而此最佳時差之評估時段則為連鎖群組最佳週期之最小公 倍數(LCM)。此外，並研擬當關聯群組於時差連鎖形成衝突現象時，整體路網時差連鎖衝突 切斷點之判斷邏輯。經由實例研究結果顯示，本群組間時差最佳化控制邏輯可提供較佳之控 制績效。

　　　　　The traffic signals are grouped into subnetworks to design a coordinated traffic signal system in urban areas. Two adjacent subnetworks usually do not have the same optimal cycle lengths in most cases. The optimal offsets between adjacent subnetworks should be determined to ensure the coordination of signal groups and increase the performance of the overall signal system. A concept of "Progression Possibility" is developed for optimizing the offset between adjacent subnetworks. The evaluation period of optimal offset is the Least Common Multiple (LCM) by optimal cycles of coordinated subnetworks. In addition, this research also establishes a procedure to eliminate the phenomenon of offset conflicts for subnetwork coordination. A case study of urban street network is presented. The results show better traffic performances by the control logic with optimal offset for coordination of signal subnetwork interfaces on progression objective.