For anyone who cares... I got a 1 minute warning on an approaching Maryland Sheriff while on I-95 last night. I was going 70 mph, got a strong K-band alert for at least 1 minute before the sheriff emerged from the pack of cars behind me, caught up, and passed me going ~80 mph... that 10 mph difference equates to ~0.167 miles. Though considering it could easily have been more than 1 minute, and the sheriff certainly could have been going a little north of 80 mph... the detect could have been as far as 0.25 miles (plus I was in one of those dangerous zones between packs of traffic, so there was noone ahead of me to help reflect signals).
I was very pleased.
I also got some pretty good constant-on X- and Ka- encounters despite heavy traffic... definitely enough advance warning to easily slow to PSL.