I think that the point of this thread should mention that a driver should be paying attention to the speed limit signs...That's why they are there.
The problem comes when you can't see them, because they're not there or because they are intentionally hidden or otherwise obscured.
When you are driving along in a certain speed zone and there is a change in that speed limit up ahead, there is supposed to be a sign at least 500 feet before the change informing you that a new speed zone is up ahead.
The trip between Memphis and Jonesboro, AR takes you along US Hwy 63, which is destined to be the new I-555, eventually. You exit off I-55 onto US 63 and find the speed limit to be 55 MPH. No sign that tells you that, though. Well, there is, but you have to know where to look for it. And going 56 MPH will get you a $200 ticket from one of two Gilmore, police officers. They write an average of 450 tickets a month.
West Memphis writes an average of 224 tickets a month. Over in Memphis, TN, population of three quarters of a million, they write about 500 tickets a month. Gilmore has a population of 331 people. And they write 450 tickets a month, and fully 90% of them are to out of state motorists. Very few out of state motorists come back to contest the tickets.
US 63 isn't just the route to Jonesboro, it's the route to the gateway to the Ozarks, to Branson, one of the major routes to Eureka Springs, where more than 1 million people a year flock to see the "Passion Play", one of the most impressive outdoor stage productions, ever.
Coming back the other way from Jonesboro to I-55, the speed limit abruptly, without warming, changes from 70 MPH to 55 MPH.
Further on towards Jonesboro, and towards the Ozarks, comfortably into the 70 MPH speed zone, there's a 500 foot stretch where it once again drops to 55 MPH without warning. Welcome to beautiful downtown Tyronza, population 918, where they managed to make ticket writing an art form, except you don't actually pass through town, you're on the by-pass. They have 12 police officers who write an average of 250 tickets per officer per month, with an average ticket being $200. The math is staggering.
The Arkansas state legislature recently took a close look at Gilmore, Tyronza and a few other places around the state (including the twin towns of Walnut Ridge and Hoxie, where doing 36 in a 35 will get you a $400 ticket). They passed legislation limiting the total amount of ticket revenue to 30 percent. They also required the speed limits and speed zone changes to be clearly posted and not obscured in any way.
Both Tyronza and Gilmore immediately annexed a lot of land and dramatically expanded their city limits, which has the side effect of wiggling through a loophole that allowed a higher percentage of ticket revenue. They still write a lot of tickets in these places, but it's not nearly as crazy as it used to be. At least the speed limit and speed zone signs are now clearly posted, and they have apparently stopped clocking people for doing 77 in a 55 even though they were actually going 65 or 70 in a 55.
There are lots of places in the US besides Arkansas where, if you have out of state plates, it's best to go about 5 MPH under the posted speed limit, that is, if you see it posted at all.