Here is a demo of the NEXYAD module Visinex Onboard that measures visibility for ITS applications and onboard road safety and adas applications :

NEXYAD Adas VisiNex onboard

To read more and watch real time demo : https://www.youtube.com/watch?v=_Lp48uGpihI 

  More demos and information on http://www.nexyad.com/Automotive-Transportation