One town that I go into regularly seems a little shaky on their posting of the speed limits. The limit up until the town is 55MPH. Next thing you see is a "25MPH speed zone ahead" sign and then the 25MPH sign is placed less than 3 seconds from the "warning sign" at 40mph. One can't even see the real sign when approaching because of the "speed zone ahead" sign being so close to it. The signs are fairly small and you're approaching going downhill. To make it worse still, sometimes one needs to drop 35MPH as it's a school zone as well. Seems to me that going downhill and being expected to drop 30MPH of speed in such a short distance wouldn't be quite legal. What's the legality of a situation like that in Illinois?