Mean Time to Hazardous Event [Transportation] Law and Legal Definition

According to 49 CFR 236.903 [Title 49 – Transportation; Subtitle B -- Other Regulations Relating to Transportation; Chapter II -- Federal Railroad Administration, Department of Transportation; Part 236 -- Rules, Standards, and Instructions Governing the Installation, Inspection, Maintenance, and Repair of Signal and Train Control Systems, Devices, and Appliances; Subpart H -- Standards for Processor-Based Signal and Train Control Systems], Mean Time To Hazardous Event (MTTHE) means “the average or expected time that a subsystem or component will operate prior to the occurrence of an unsafe failure.”