It must have seemed like it was raining concrete at the Dixie Highway viaduct for a few days in mid-April. On April 8, police received two reports of debris falling from the structure, hitting cars and damaging windshields, and on April 10 a report was filed of someone throwing rocks at vehicles in the vicinity. “Raining” might be a bit of an exaggeration, but the incidents point to a problem that an umbrella will not address. The latter (rock thrower) is a problem the police will try to solve by apprehending the culprit if . . .