Watch it coming down Nelson Street from Route 28. Montgomery County/Rockville police sit in the parking lot of the Christian Science church where you cannot see them. The speed limit is 25 mph, but it’s hard to maintain that coming down the hill (and most people don’t even try). Police also bust drivers coming from the other direction. All are pulled into the church parking lot, so the ambush is able to continue. Admittedly, this is a highly residential area including a bike lane, so motorists generally should cool it anyway.