A big tradition here in Louisville is "Thunder Over Louisville". This starts the celebration for the Kentucky Derby. 'Thunder' is an airshow, fireworks, fair, concerts, and a nice day out along the river. This event leads to the closure of bridges over the Ohio River. Some closures are brief, such as I-65. Others are days long because fireworks and other aspects of the theatrics are positioned there.
We have a new pedestrian bridge called "The Big Four Bridge" which was opened very recently. This bridge is closed despite being a very obvious attraction to attendees and it can ease car traffic by allowing foot traffic across the river. There are many notices that this bridge is closed, but none of them cite the authority that closed the bridge.
Does the FAA hold sufficient authority to close bridges, roadways, or other locations for an airshow?
If so, what resources should I use to locate these closure notices?
This question is simply a curiosity. There are many logical reasons for the 'Thunder' organizers, local police, state police, and the FAA to close the pedestrian bridge. I want to learn more about what authority the FAA specifically would have in this matter just for the sake of learning.