Puddles
duplicate image layer, flip it so its upside down, pull it up so the horizon line matches the donor image, layer mask paint out the negative areas to create puddles on the road, you need a sharp edged brush, paint the puddles in you will notice the reflection, you need to stretch it slightly and consider using gradient filters in the mask to replicate fall off. To get a decent bevel on puddles consider using the bevel and emboss tool make sure the global light is going in the right direction.
Wet Sheen
For wet surfaces you can do the above, apply a motion blur filter (vertically), using the smudge tool add some ripples, lower the opacity and move the layer so it looks right on the scene. Once again use the layer mask consider using the gradient filter to replicate fall off. paint out parts of the layer which are not on the ground plane. Remember to vary the opacity in the scene to prevent it looking to fake.
There is a lot of manipulating it into place to get the right perspective, just take your time play with the blend modes, tip at night the reflections highlights are about a 1/3 of a stop greater and the darks are a third of a step lower, (I think this is a optical effect due to specularity)
Hope this helps
Rich
This is what I would call an omelette question as each person has there own way of making it. Just throwing you some techniques that I have used in the past.