I don’t know the data on locations of glider/glider collisions for
USA, but in the UK most are near the home base gliding site of the two
gliders. A few are on cross countries, and even then some are with
another pilot from the same club on the same task.

For which reason, I have been advocating that anybody obtaining Flarm
should do their best to persuade other glider owners at the same site
– club or private- to fit it too, for the most effective improvement
in alerting.

And, by the way, here in Euroland, where the simple Swiss Flarm is now
OK to fit, many of us do it as a piece of personal carry-on equipment,
with its own battery if there is not an easy way to plug into the main
glider electrics, to overcome officialdom’s need for approved
modifications. I do that on my glider.

Chris N.