https://apnews.com/bd268909e7f4aff4b3ef3680c9258bc9 > A 50-year-old bridge that collapsed in Pittsburgh had been rated as poor on a recent inspection report, but transportation officials and engineering experts cautioned that doesn’t necessarily signal imminent danger for the thousands of other U.S. bridges with the same designation. > Investigators from the National Transportation Safety Board and the Federal Highway Administration have been combing through rubble from the collapse early Friday of the Forbes Avenue Bridge, looking for what caused it.