Northbound 395 entering Kettle Falls
Police will usually wait off to the side as you enter the city and snag anyone going too fast. The speed limit drops from 55 to 35 in a fairly short distance, but there is a "Reduced Speed" sign prior to hitting the city. If you release the gas pedal as soon as you cross that Reduced Speed sign, most vehicles will coast down to the proper speed by the time they hit the city limit.
Warning: The police vehicle they have been using is usually the dark coloured one which is difficult to see. Just assume they are there and save yourself a ticket.