I used to drive 5 to 10 over every speed limit and get passed.
But rexburg, yes. Their limits are ridiculous. But probably because it's full of too many college kids for the size of the town. Combine idiot drivers (LOTS of Californians at school there) and even more idiotic pedestrians all looking down and thinking they can do what they want, and they wonder why people keep getting hit by cars there.
Then add in a ridiculous amount of cops... highest number of cops per capita in the state is in Madison county, probably the most harmless county.... too many cops equals boredom and pulling people over for anything.