(Portland, OR)  --  Portland police say a possible road-rage incident led to the shooting of an eight-year-old girl on Interstate 84.  Authorities say a man who recklessly drove a van along the highway yesterday fired a shot at a nearby vehicle which he had nearly caused to crash.  Police say the girl, who was sitting in the back seat, was grazed on the ankle.  Authorities say the suspect, identified as Joshua Constantine, was later arrested near 162nd and Stark.