sorry everyone. I thought panning could also be the movement of the object while everything else is still... Now I really regret it since a shot like this would have done really well in leading lines...
Woops is all I can say, sorry for the confusion, and thanks to all who liked the image anyway. :)
Some people will say that this is not panning. You just need to tell them that your subject (the bridge) is in motion and your camera tracked along with the bridge while a background car blurred by (it's foreground, but hey, it's all a matter of perspective).
Seriously, I love the long exposure shots like this. It doesn't meet this challenge, but you might find an angle on this shot that would meet the leading lines challenge very well.
This is very interesting and I appreciate the abstract quality. My only complaint is all the negative space. The colors and lighting work well together.