Concrete fell again this week from the Interstate 5 overpass in Oceanside, Calif. The incident stalled traffic for two hours. This is the third time concrete has fallen from the overpass in one year, but the state DOT says the situation does not put drivers in danger. "We are confident in the structural integrity of the bridge," a Caltrans spokeswoman said. "We're not afraid that it's going to collapse today or tomorrow."