Here in my area we have more paved then unpaved paths. Most of the paved paths become very difficult to ride during winter time, that's why the average cyclists just puts their bikes away into storage during winter. I've ridden them during winter many times and it takes a tremendous amount of effort to pass through them, often requiring getting off the bike and walking..... The problem with unpaved paths in my area which are made from crushed stone and gravel is that they become a big mess after winter snow/ice melt. They require some serious maintenance throughout the year, I have also seen heavy rains and flooding wash away and cause damage to parts of these unpaved trails. They would not be easily passable on a bicycle if the city didn't maintain them.