Gianni Ferraro, 31, the son of Los Angeles City Councilman John Ferraro, was arrested on suspicion of drunk driving after his car ran down and seriously injured a pedestrian at a Hollywood intersection, police said. Breath tests given to Ferraro at the time of his arrest showed alcohol blood levels of .23 and .25, more than twice the legal limit of .10, Police Sgt. Richard Brownell said. Ferraro was booked on suspicion of felony drunk driving after his 1985 Nissan struck an elderly man who was walking across Hollywood Boulevard at Argyle Street. Brownell said Ferraro was attempting a left turn. The pedestrian, Walter Shard, 69, was hospitalized in serious condition with cuts and a concussion, Brownell said. Councilman Ferraro was in Argentina, an aide said, and will not be available for comment on his son’s arrest until his return today.