Agency technical experts review each and every call, letter, and online report of an alleged safety problem filed with NHTSA. Although NHTSA has no jurisdiction over defects that are not safety-related, it does review each report that suggests a potential safety defect involving groups of motor vehicles or vehicle equipment. There is no established number of reports that must be filed before NHTSA investigates an issue. The agency's Office of Defects Investigation investigative process consists of four parts: