Hi
I also think that this might not be the best image do use selective coloring.
For me an image should have a focal point (of course there is exceptions to that) that attracts your eye. It should be rewarding to look at and hopefully give the picture some sort of meaning or story behind it. I think that's what sets a good picture apart from a snapshot.
Maybe you indented to tell a story by highlighting the billboard. But I think for us the viewers it isn't apparent what your message is. Therefore I think this image doesn't keep the eye interested for too long.
I like the coloring as a compositional element in this image. It's almost using the rule of thirds (although a bit pushed here). Also technicaly how you used Photoshop (I'm guessing) to color it is pretty good.
But for me personally, all of this is not enough to make an appealing image..
I don't mean to sound rude or anything. Afterall this is a place to critique work and I hope I'm making sense. I also might be way off and you do have a good reason for coloring the billboard. Please let us know...
Anyway, thanks for sharing your work.
simon