So what caused the collapse—the design, the construction, or the ABC technique? There won’t be answers until the National Transportation Safety Board, which investigates civil transportation accidents, completes its investigation. But, Myers says, “something triggered it”—be it job site processes, design or manufacturing issues, or a combination. “There’s something there.” FIGG Bridge Engineers, Inc., the designer of the bridge, says it’s cooperating with authorities. "In our 40-year history, nothing like this has ever happened before,” the firm said in a release.