"Whose road is it?"
Translation:De quem é a estrada?
You are talking about a specific road so I don't think it's not possible to leave out the definite article "a".
To see how strange it is without it, try taking "the" out of "to whom belongs the road?". In English the define article is "imbedded" in "whose".
That would be "who is the owner of the road." Similar, but not what the question wanted unfortunately.