Dreams are vehicles used by the subconscious mind to communicate with us symbolically. Sometimes there are words, but most of the content of dreams is visual.
When your subconscious mind knows that you are in trouble (or headed for trouble), you may not dream specifically of road signs. That would be almost too easy. On the other hand, you may.
Have you ever dreamed of a Stop sign, or a Wrong Way sign? If you ever do, pay attention. Your inner self is trying to tell you something