In Rochester,Illinois near the only stop light in town. This stoplight is on a moderate downhill grade, the officer uses radar while sitting in the high school parking lot moderately above the street. The posted speed limit is 45 miles per hour. Here is a "hint" for truckers, Illinois puts a "speed limit" sign on the same post as the sign that designates the population and name of the city. State law says 30 mph. for urban streets and 20 mph. for school zones on days when school is in session. Speed limit signs for schools read "school zone" in bright yellow at the top of the sign.