You wouldn't have short sections of road where the speed limit is reduced for no apparent reason.
Oh, but usually there is a good reason, although not an apparent one.
The highways out here are pretty empty, and so there's no competition for "getting ahead" of the other guy.
Once in a while one will come to a straight, endless, stretch of highway where the speed limit's abruptly reduced from 60 mph to 50 mph or even 40 mph.
One at first thinks, "WTF?"
It's usually because the winds are known to (usually) be really strong on that particular stretch, and can blow a car off the road. It's for one's own safety.
I also think that, at least here in Nebraska, an ancient law which used to pertain but which doesn't anymore, should be restored; that of after sun-down, the maximum speed-limit is ten miles lower than the posted speed limit.
And then during deer-crossing season, it should be no more than 45 mph.
I'm one of these rare people around here who's never hit a deer; I've come close however, and if I'd been going 60 mph (the actual usual speed-limit), I wouldn't have had the time to evade.
I'm in a hurry just as much as the next guy, and sure, driving endless expanses can be boring.
But on the other hand, how much time am I
really saving, by going 45 miles to the big city, at 60 mph instead of 55 or 50 (I drive according to conditions on the road, up to but not past the speed limit). Thirty seconds? Forty seconds?