Unmarked police car (black ford truck) monitoring southbound Hwy-20 traffic, travelling from Yellowstone park to Idaho Falls, going through Ashton City. Speed limit 65 mph. Cop had parked off road, and turned off all vehicle lights in dusk/nightime, and entered hwy 20 from 1455/E 1425 N road to pursue car approaching city limits, before the hwy 20 speed limit 65mph turns to 45mph. After the Big Bend ridge, the following downhill and flat straight line is over 1.5 miles, allowing visual speed assesment of hwy 20 cars from perpendicular 1455 road (on right hand), followed by radar speed assessment, once patrol car has entered hwy 20. Possibly cop was driving some portion of hwy 20 without lights on to first lock in a radar readout.

5/2008