The Witness - Who you think you are.
The Vehicle - What you say, think, do.
The Attractor - Your Uniqueness.
Roads and tunnels is the phrase that Human Design uses to refer to the definitions in our charts that appear colored in black or red when the chart is calculated. The calculations appear on the bodygraph in these two colors to indicate what gates were activated at the time of our birth (the black) and what gates were activated 88 degrees of the sun's arc, almost three months, prior to our birth time (the red).
We can think of the bodygraph as a road map and consider the throat center as the nexus or town square of the map. From there you can travel in any direction – up or down through the different pathways. The throat center is central to a bodygraph because it is through the throat that all of our behaviors (centers, channels, gates, and lines) are manifested or expressed. In this sense all roads lead to Rome. But there are also tunnels.
Whatever you see in black in your chart refers to personality and it is what you have access to – this is who you think you are. Access in the sense that the behavior can be obvious to you, seen by you. Think of the black in your chart as a surface road. Sitting on the side of a hill, you can watch everything happening on that road and (here's the key) because you can see it you think that is who you are.
Whatever is colored in red in your chart refers to design, to the unconscious, and is more like a tunnel than a road. Sitting on the side of a hill, you can't see what is going on in the tunnels. In fact you can't even see that there is a tunnel, nor whether or not anything is inside it, or if anything is moving, nor in what direction it might be moving. But (another key) what's going on in the tunnels is also you.
One of the real advantages of the Human Design bodygraph is that when you look a chart, you get to see it all. You see what is on the surface and what you therefore have access to (the roads). And you can also see what you don't have access to – your unconscious or that which is unrecognizable in you (the tunnels).
Now you must understand that the behaviors, be they conscious or unconscious, are going to somehow find a way to express or manifest themselves. It's in the nature of the energy that it flows and wants to be expressed in words or actions. The behaviors don't care whether or not you have access to them – they just want to express themselves.
This can be referred to in Human Design as having something just pop out of the tunnel, and then have it go back under again. It's not uncommon for people to hear something like "Boy you are really argumentative or stubborn or judgmental," etc. and we don't see that in ourselves at all because it is a tunnel, i.e. a Design definition.
For example, someone who had the channel of leadership unconsciously might be the one who sends everyone out of the building to safety when there was a fire. But this person would not describe themselves as a leader, and would be surprised if told that they were.
Before human design, access to our unconscious aspects was a matter for Freudians to reach through dream analysis and for Jungian psychologists to posit existed in a collective realm. Now it is possible to comprehend what others see in us that we don't because it is unconscious.
There is now a possibility of understanding where that behavior that popped out of a tunnel came from, as well as the fact that it is a consistently defined part of you. You can begin to have a more complete idea of who you are. Not for the purpose of changing it, but for the purpose of living it, accepting it and enjoying it.