Humans are in many ways obsessed with the dark in a negative or positive way because of what could happen. There is nothing more ominous then, than a dark road, and this is what makes it an even more important dream symbol.
If you have a dream in which you are travelling a dark road then this dream means that you are going down a path you are not 100% sure of. There are a lot of reasons why you might be frightened of this path, because it is unknown and we people are afraid of the unknown, but there are also a lot of reasons that you should not be afraid. You are trying something new so you should be more excited about that than you feel about anything else. Remember how fun life can be? Don't be scared to try new things or go new places at all.