My entry into the Stock: Fitness challenge, made into a billboard with added type, graphics, and photo.
Entry:
It was, of course, trashed for the blur ...
The presence of sharp images in the foreground renders the blur of the background image largely irrelevant, as the eyes will focus on the sharp parts of the scene -- the message -- especially when it's probably going to be viewed briefly from a moving car. The sharp type and inset image also make the blurry BG appear to be a DOF artifact.
The blurriness of the BG image is also helpful in making the image usable as stock without a model release, this version has additional blurring* to make sure none of the figures is recognizable.
*Gaussian Blur at about 4 pixels on the DPC-sized image