The French Land Transport Accident Investigation Bureau (Bureau d'Enquêtes sur les Accidents de Transport Terrestre, abbreviated BEA-TT) is an agency of the French government formed in 2004 and charged with the investigation into accidents involving all forms of land transport, including railways, urban guided transportation systems (metros, trams), cable-hauled transport systems, road transport (heavy goods vehicles, and public transport by coach and bus), and canals and other navigable inland waterways. It is headquartered in the Tour Voltaire [fr] in La Défense business district in Puteaux. From Wikipedia