On I-90 just west of Mullan, Eastbound lane
East of Wallace, just west of Mullan. Rounding a sharp curve, the speed limit abruptly changes from 60 to 55 without warning. The sign is hidden by the curve and not visible until you are within 50 feet of it. There is very frequently a ISP or County Sheriff sitting there, just off the roadway in the shadows. I have seen enforcement details consisting of as many as 5 cars pulling over people that did not slow down in time.