The Double Decker represents your path through life as part of a collective. The "top deck" offers a higher perspective, while the "bottom deck" is about the immediate reality of the journey and its stops.
Spiritual Significance
It symbolizes the "Great Wheel" of public life. You are part of a larger movement, and your destination is fixed by the route of your current social or professional environment.
Psychological Perspective
The shadow is the "Loss of Autonomy." Do you have a ticket, or are you just riding because everyone else is? It asks whether you are looking out the window or at the other passengers.