It's often the case that after you've been sitting for a while in an(other) ATL traffic jam, the congestion suddenly (and inexplicably) begins to clear up without any sign at all of what caused the delay...  

I'm not saying that something like this causes those random traffic jams, but I'm not saying something like this doesn't cause those random traffic jams either....

Here's one of the preparatory sketches for the piece:

The finished piece is roughly 20x30 inches and was done using pencil, ink, watercolor, and gouache.