You are driving past a school, less than 500 feet from it, and there are children outside or crossing the street. Unless a lower limit is posted, what is the speed limit?

Why

The default limit near a school is 25 mph, and it applies within 500 feet of the school while children are outside or crossing the street. The handbook notes that some school zones post limits as low as 15 mph, so a posted 15 mph sign overrides the default, but 15 is not the baseline. Fifteen is the number the handbook attaches to other places: blind intersections, alleys, and railroad crossings where you cannot see the tracks for 400 feet. Near a school, look for crossing guards and school safety patrols and obey their directions at all times, and watch for stopped school buses: yellow flashing lights mean prepare to stop, red flashing lights mean you must stop.