High Quality Content by WIKIPEDIA articles! Public roads in Romania are ranked according to importance and traffic as follows: motorways (autostrad - pl. autostr zi) - colour: green; designation: A followed by one digit expressways (drum rapid or drum expres) - colour: red; designation: DX followed by one or two digits and an optional letter national road (drum na ional - pl. drumuri na ionale) - colour: red; designation: DN followed by one or two digits and an optional letter.