If you're on a road that goes through a town just barely large enough to have a police department, you can guarantee that the road suddenly gains a posted limit of 35 MPH without changing in any significant way and that there will be strict enforcement which may or may not be biased towards those with non-local tags.
The exception is the state of Indiana. I don't know what they put in the water there, but no one in Indiana seems to have noticed that interstate highways are no longer stuck with the double nickel. Of course they also have the most bare minimum 2+2 interstate where one dawdler refusing to pass a semi can tie up traffic for miles on end.
Regardless, “the right enforcement” thing is clearly true, but the right enforcement isn’t necessarily practical. Some of the worst offenders I’ve seen wrt speed limit aren’t (imo) highways where people go 15 over, but really wide locals in suburban residential areas where people come off the highway and keep driving 40+, putting bicyclists or pedestrians in danger. These roads are rarely enforced by traffic cops probably due to how little traffic they see in the first place
Smalltown cops are bored.