The s-curve is a nice compositional element. If there had been a greater dof, this would have been one of the best windshield shots. As it is presented I gave it a 4.
I really like the way you captured this one. At one point during the week I was driving through a deluge and didn't have my camera, I was seeing a very similar shot, I really like the roads curve in the shot.
I know what you are trying to get at but a picture of a wet windshield with smudges on it does make it very interesting photography. Maybe if the drops were bigger and the landscape in the back werre to be refracted in them. That could make it alot more interesting. As it is now, there something to see through that windshield but I can't see it cause of those damn drops and smudges. Good luck
As with some other shots of this kind, I wonder if you might not have benefitted from greater depth of field; the road and landscape are perhaps too far out of focus for comfort. I like the idea, but the streaks of the wiper blades don't seem to add much.