A metro cop observes vehicles along his corridor, in this case, a monocycle. The thing on the rider's back could be some kind of booster, but I'll leave that up to your imagination. Note the cycle's power source is illuminated and located above the tire.
I started off with Painter and refined it with PS.
I have no idea how you always have such perfect color scheme.
I had a similar monocycle idea but it never went beyond sketching stage.