I think the vehicles they see on sonar are that of the eight workers that were on the bridge filling potholes. Two have been found one critical condition. One walked away with no injuries. Six workers are still missing. If you watch the video, it looks like it’s the workers trucks with the lights flashing that went into the water.
thank goodness the ship sent the Mayday out and they were able to stop the flow of traffic in both directions fairly quickly.