The posted speed limit is the max speed.
the posted speed limit
826 limit
You can be ticketed for traveling at an unsafe speed regardless of the speed limit.
Whatever the posted speed limit is.
When it is flashing the speed posted is the limit
The maximum speed limit.
If the posted speed is not safe at that time
When another speed limit sign is reached that changes the limit from the previously posted one.
Whatever the posted speed limit is.
Varies by jurisdiction. Ultimately, it will be whatever speed limit is posted.
40 mph