群組劃分為時制設計中之重要步驟，且於群組劃分完成時，各群組依其群組內各路口之交通特性產製合適之時制計畫並加以執行，但此類時制計畫僅對群組內各路口于以連鎖，並未考量群組間相鄰兩路口連鎖的問題，因此若兩群組間相鄰路口連鎖不當時，則群組間上游路段極易產生交通壅塞現象，進而造成上游群組內各路段之車流無法順利運行，嚴重影響交通控制系統的整體績效。本研究建立－程序性之群組問時差制定流程，其績效指標係以最大總續進可能值為主，再輔以最小總停等延滯值作為考量，且分析雙重到達率、雙重好解率及過飽和等狀況以推估更合理之延滯值。為便於了解，本研究列舉兩個實例以供參考，交通工程師可依據此概念設計號誌群組間之時差，以增進整體號誌路網之運作績效。

Signal subnetwork determination is one of the most important steps of signal timing design. In most cases, two adjacent subnetworks do not have the same optimal cycle lengths by their individual traffic characteristics. Such signal timing plans can only reflect internal coordination for specific signal subnetwork without concerning the overall road system performances . The phenomenon easily results traffic congestion by unsuitable coordination at the interfacing intersections. This research considers minimum delay based on maximum progression by sequential design process. The operation performances are conducted by dual arrival rate, dual saturation flow rate and over saturation conditions for delay calculations and “Progression Possibility” for progress effects, respectively. This paper presents two case studies to promote understandings of this approach. Traffic engineers can apply the offset design concept for signal subnetwork interfaces to increase overall performances of integrated signal networks.