Ed, MIT/LL is being funded by FHWA to expand upon its' research on utilizing video camera images for measuring visibility (and potentially other weather/road variables). Here is a link to a paper presented at the Mid-continent Transportation Symposium that details work-to-date. http://www.ctre.iastate.edu/pubs/midcon2005/HallowellImagery.pdf The University of Minnesota and sever Japanese weather organizations have also been investigating the use of camera imagery. References to papers from those organizations and others are contained within the symposium paper. Please feel free to contact me if you want more details. Robert Hallowell Weather Sensing Group MIT Lincoln Laboratory (781)981-3645