Where I live we have some really nice trails to use for biking and running, my concern though is my personal safety. I've never had any incidents where I have felt uncomfortable by someone else on these trails but there are a lot of crazy people out there and there's always a first. I bought a mace holder for my bike that attaches to my handlebars but I have to wonder what else could I do. It would be ideal to have a friend go along with me but sometimes that's just not possible and I don't want to sit at home on a nice day with a perfectly good bike because of something may or may not happen. I'll usually go on the weekends when there are more families and groups going out. We also don't have a lot of bike paths on the roads where I live and honestly I'm more scared of those than the trails, no one pays attention to them.
Anyway other than mace, having my bike properly maintained and telling someone where I'm going is there anything else I can do?