Many years ago we experimented with a proposed system that used bottled gas (don't recall just what it was) but it was a total failure. I would think one could spend lots of money and time trying to disipate fog and as long as Mother Nature is cranking out the fog you will be in a never ending battle. George Small Assistant District Engineer - Traffic Maryland State Highway Admin. -District 6 1251 Vocke Road LaVale MD. 21502 301-729-8440 1-800-760-7138

I did a www.google.com search on keywords (dissipate fog dissipation) and then (dissipate fog dissipation FHWA). Here are a few related citations: 1) http://www.wmo.int/web/arep/wmp/ECWPCCWM/DOCUMENTS/Doc4.3_chalon.doc 2) http://www.usroads.com/journals/rmej/9801/rm980101.htm 3) http://www.topslab.wisc.edu/resources/NHVC_presentations/tsrvisibility.pdf 4) http://ntl.bts.gov/lib/2000/2900/2933/fog.pdf 5) http://trb.org/news/blurb_browse.asp?id=5 see 228 - Reduced Visibility Due to Fog on the Highway 6) http://www.udot.utah.gov/dl.php/tid=297/UT-02.12.pdf The NHVC website at http://knowledge.fhwa.dot.gov/nhv is a good resource, too. You can do searches or look at the Reference tab (http://knowledge.fhwa.dot.gov/cops/hcx.nsf/home?openform&Group=National%20Highway%20Visibility&tab=REFERENCE). Related to this, the Conference presentations: http://www.topslab.wisc.edu/resources/nhvc.htm. I'm not personally aware of significant successes with the dissipation of fog, but your specific situation may warrant further investigation. Best regards, Nancy Mark Mark R. Chandler, PE, CMfgE U.S. DOT - FHWA Wisconsin Division 567 D'Onofrio Dr. - Suite 100 Madison, WI 53719-2844 office: 608-829-7514 fax: 608-829-7526 mark.chandler@fhwa.dot.gov http://www.fhwa.dot.gov/widiv/index.htm Asst Coord for WisDOT's SW & NE Regions Technology Transfer/Quality Engineer; Research, Marketing

For "dispersal" has been used in the aviation community for decades. Try a Google search for "fog dispersal" and you'll find a wealth of information. I'm personally aware of the US Air Force system that was (is?) used at Fairchild AFB near Spokane, WA. The system was very successful dispersing supercooled fog so that aircraft could take off and land. The only problem, which depended on the wind direction, was that the dispersal of the supercooled fog caused snow to fall downstream. The USAF would notify the WSDOT in the area so that the highways in the area would be treated or taken care of. This presents interesting considerations for fog dispersal in the highway environment.

There are simple passive systems that can reduce fog density and increase visibility on highways. These can be appropriately chosen plantings of selected tree species or large fog collectors made of inexpensive mesh. FogQuest is a registered charity that provides water to mountain villages in developing countries using fog collectors. The same technology can be used to reduce the amount of fog on highways. It has been employed in Japan where visibility in fog has been more than doubled on highways that have been lined with fog collectors. Examples of the fog collection process can be seen on the FogQuest website (www.fogquest.org). Dr. Robert Schemenauer Executive Director, FogQuest