I 57 enters Illinois at Cairo. The Speed limit is 70 in Missouri, and 65 in Illinois. Alexander County uses this to trap and ticket travelers that had been driving 70 mph. I recieved a ticket from an Alexander County deputy. I was leaving Illinois and was already driving 65 mph. I was was ticketed for 79 mph. I am 60 years old and I never drive 79 mph. Watch out for them. It is strictly a money trap! I was well over 1500 Fort around a slight curve, with an overpass between where he was and my location when he clocked me. I have a witness that I was not speeding! I will have my day in court.