I actually saw this on a German TV Show (The Lion's cave), where the inventor pitched it to a group of investors, they were very fond of the idea but no one actually wanted to invest right a way, at the end he got himself a deal, for quite a big share of his company.
Anyhow. Interesting idea, to move the adds and make the suitable for the part of the road or country you are actually driving through. I am a bit concerned about the safety though, looking at can distract you pretty much, well, but so is if looking at an app like Foursquare.