Rear of a warning signs bearing the indication tutti i veicoli - tenere la destra (all vehicles - keep right). Introduced at the end of 1920s and used unitl the begin of 1930s by the RACI (Royal Automobile Club of Italy).
Motu proprio : cento anni di ACI, per andare avanti, Automobile Club d'Italia, 2005, Roma
Original:  Reale Automobile Club d'Italia (RACI)

Vectorization:  Earthshaker13