I'll go so far as to say, for me, I actually feel safer riding alone crazy as that sounds. True if you have a fall, having someone else around is helpful, however, I honestly feel that riding with others increases my chance of falling in the first place.
Of course the most important thing when riding alone is being sure you are on a horse than can be alone and not freak out. I'm not at a skill level that I'd take a buddy sour or green horse on the trail alone. It has to be a steady eddie.
So far, almost all of my close calls have been a result of someone riding too close to me to pass and their horse kicking out almost hitting my leg (some trail riders have NO sense of personal space), someone freaking out over a snake on the trail causing their horse to freak which resulted in a string of spooking horses, someone freaking out going up a muddy hill and stopping their horse causing a pileup of sliding horses....you get the picture.
When I'm alone I only have to think about me. I also have to think about what would happen if I did get hurt. So I always
1)carry my cell phone on me
2) wear my helmet
3) have my name and info written in my helmet
4) tell someone where I'm riding and about what time I'll be back. I'm not out in wilderness. I'm on local trails so it wouldn't be hard to find me. I always call my husband or my mom when I'm done. If they don't hear from me by around a certain time, they know I'm in X park on X trail.
and last, the greatest invention ever..
5) SPOT SATELLITE MESSENGER :: HOME PAGE
I have a serious crush on my findmespot. Forget sending a person for help. You can send for help wherever you are. FAR more efficient than sending another rider for help.
I remember trail riding when I was younger and I loved having a group and just yapping. Now not so much. I prefer the peacefulness of the woods and time with my horse. I don't slow anyone down and they don't slow me down.