A cement mixer sticks out of a hole Friday afternoon on the Davis Islands bridge in Tampa. The unoccupied truck, parked near a construction site, rolled backward and fell through the hole onto a barge below. No one was injured, but the accident blocked traffic on the westbound bridge for several hours, Tampa Police Sgt. W.R. Dial said. The other bridge, which usually only carries traffic onto Davis Islands, was opened for traffic both ways, he said. Workers called a tow truck and brought in a large crane to lift the cement mixer.