Supplementary Safety Measure [Transportation] Law and Legal Definition

According to 49 CFR 222.9 [Title 49 – Transportation; Subtitle B -- Other Regulations Relating to Transportation; Chapter II -- Federal Railroad Administration, Department of Transportation; Part 222 -- Use of Locomotive Horns at Public Highway-Rail Grade Crossings; Subpart A – General],supplementary safety measure (SSM) means “a safety system or procedure established in accordance with this part which is provided by the appropriate traffic control authority or law enforcement authority responsible for safety at the highway-rail grade crossing, that is determined by the Associate Administrator to be an effective substitute for the locomotive horn in the prevention of highway-rail casualties.”