It is an important social mission for West Nippon Expressway Co., Ltd. (following NEXCO West Japan) to continue the wide expressway network operations against various risks. This paper reports on process of the business continuity plan development aimed at the establishment of the standardized crisis control system and efficient expressway operation by applying both BFD (Business Flow Diagram) and CPM (Critical Path Method) through the case study at NEXCO West Japan. Especially, it also can be shown that the introduction of CPM for WBS (Work Break Down structure) of emergency behavior is effective to find critical path and to decide the priority of countermeasures against various risks under cost restraint.