What happend with your experience due to the traffic light simply means that you did control its light (sign). I know this because if you practice with a die, and will the number to land on 6. It will land on 1. Thats how it works most of the time. So don't worry your not a weirdo!
What you simply have to do, is concentrate and close your eyes, and try to tell your subconscious while thinking of the die, exactly what the number on the die are. But while doing that, may more attention to the numbers yours subconcious is messing up. (for example: six has six dots) (One has one dot)
That should make it more easier. Its just a matter of practice-and truth to be told, this is known as micro tk. Its when you force something to happen or will some object to do what you want. But not move. For moving objects is macro-tk.