Wait, you're seeing this hand from the driver's side mirror. Not unless you drive in another country aside from the US I guess. I like this shot. It expresses rain yet doesn't really make it obvious.
The raindrops are mostly sharp as tacks, and I like the message in this image. I'd like to see more focus on the hand, though. I like the framing done by the mirror, by the way. (except I might have made sure the frame also covered or touched the lower right corner). Your entry is very relevant to the challenge.
Nice shot - one thing that bothers me though is the fact that it's obviously a fairly well dressed woman hitchhiking (not very likely). Still good shot.