Single track is one thing. But, one popular area around here has a pretty solid explanation. A trail could easily have two dramatically different ratings one way over the other. Suppose a new rider/driver finds they over estimated their abilities a quarter way through. Should they put themselves in danger after they realize their mistake, or turn around and potentially be a danger to others unaware of a wrong way rider/driver trying to get back out to the trailhead? It's a slippery subject really, but before I read that perspective, I was entirely in the same boat. Some places really could stand to go with one way systems, but its not a perfect solution everywhere.Maybe I’m alone here, but it’s hard for me to grasp and explain to myself why anyone would make tight trails two way trails...
I’ve seen single track dirtbike trails that allow traffic flow both directions with very twist twisty sections..and then people are shocked to learn that riders collide into each other....