The project execution plan (PEP) is the governing document that establishes the means to execute, monitor, and control projects. The plan serves as the main communication vehicle to ensure that everyone is aware and knowledgeable of project objectives and how they will be accomplished. The plan is the primary agreement between Headquarters and the federal project director and a preliminary plan should be developed and approved at Critical Decision-1. Project objectives are derived from the mission needs statement, and an integrated project team assists in development of the PEP. The plan is a living document and should be updated to describe current and future processes and procedures, such as integrating safety into the design process. Updates are common as a project moves through Critical Decision stages.