The trail that I like to ride is has slower traffic. Generally you'll meet someone walking or biking every five minutes or so. It does cross some majorly busy roads, but its pretty secluded in spots with nothing but trees and brush. Although the area I live in is considered safe, there have been problems in the past on that trail but in a different section that I ride in. I take my cell with me whenever I go and let my husband know approximately where I'll be.
This doesn't make me feel the safest though. And I have seen some people that make me feel uncomfortable, but for that matter when I biked home last night on a very busy main road, I encountered a person who made me uncomfortable there too. Perhaps, I'm being overly sensitive to my gut reactions or just overly cautious, but are there any ways to keep safe from people while biking?