I truly like the composition and feel of the shot, for some reason though, the separation between the riders and the background looks a bit too perfect, and haloed in spots, perhaps its my monitor, cheers on the good work.
A nice shot and very sharp on the cops 'n' horses, although there's some halo-ing around them, not sure what you did processing-wise, I'd guess you maybe burned the background to bring more focus away from the cars? It's not majorly distracting but very noticeable around the head and shoulders of the men.