That’s not how speed limits work. They are legally required to be raised if traffic is going faster:
“Once the road is built, engineers will evaluate the existing speeds by measuring the operating speed. They often do this by measuring the speed that 85 percent of drivers are travelling at or below, called 85th percentile speed.”
That’s not how speed limits work. They are legally required to be raised if traffic is going faster:
Per federal FHWS/MUTCD regulations.