the only security measures i have are vigilance and common sense.
I was thinking about the thread about the sniper shooting a bicyclist last night and the suggestion that they carry guns. If a sniper shoots you,
your gun is just one more hard heavy thing that's going to hurt when you land on it.
Guns might be useful in some situations, but while you are biking, if someone hiding in the bushes decides to shoot you; YOUR gun isn't going to help you much unless you have it mounted on your handlebars.
We used to carry rocks when riding through doggie territory but haven't had that problem much for a while.