On Wed, 10 Aug 2016 14:44:04 -0400, Tekkie®
wrote:

Pat posted for all of us...
Cars going the opposite direction DO get
detected, but they show up as going a negative speed. The built-in
software just ignores those signals and displays only positive speeds.

A negative speed? Huh? NO It's doesn't care what direction you are going.
The physics cares. A car appraoching at 35 is very different from a
car going the other way. The software might be programmed to display
the absolute value of the speed, but internally, the device knows
toward (positive) from away (negative).

The beam pattern is narrowed so it's only measuring the oncoming traffic.
That may be the intent, but real world roads have curves and cars on
the other side are sometimes detected.