While some of those ads appear to be real, quite a few are photoshop jobs - nicely done photoshop jobs though. I am guessing for someone's schooling or portfolios (as a professional designer myself, it's an effective tool to show one's skills). If you study them, you will quickly pick out the exact same truck in the same location with diff ads/background effects. Having said all that (perhaps unnecessarily, I'll admit!), I love the Zoo bus.