A vfx breakdown for two of the shots in Pedestrian Revenge.
If you're a fan of grunge on glass and want to experiment with those kinds of textures, check this site out:
http://www.cs.columbia.edu/CAVE/databases/dirty_glass/texture.php
Alternately, do a Google image search - you'll want to get pictures of dirt/smudges/etc. on a black background to make your life easier.
