The night renderings for the Jindu Project posted a couple of weeks ago had a cobble stone street that was Photoshopped to look wet. Adding a reflection such as this adds a bit more excitement to the image compared to leaving it flat. I have always liked architectural projects with large reflecting pools in front. In illustrations, rendering the parking lot or street wet can give you that same kind of look. The video below explains the pretty easy work flow of how to Photoshop a street to appear wet.