I read the challenge as creating an Auto ad, or something that could be used for the purpose of an auto ad, and not to take a photo of an auto ad. This overall picture has little appeal, the man is too dark, the surroundings are as well, and he is standing in front of the car, which obscures it, when it is meant to be the main subject.
I get the concept, nice idea. However, I think it would have worked better if the guy was to the left another four to five feet (in front of the yellow pattern) so that the image of the BMW was not blocked. This looks like an opportunity shot; maybe you could have gotten a friend to walk by the billboard and turn his/her head back looking at the BMW to duplicate the concept??? Anyways, good concept, just the composition is "off." IMHO.