1. EXPERIENCE WITH SNOW BUILD-UP ON LED TRAFFIC SIGNAL LENSES JOANNA BUSH, P.E. STATE TRAFFIC SIGNAL SYSTEMS ENGINEER Wisconsin DOT

2. Size of the Problem WisDOT currently owns/maintains approximately 950 signalized intersections. All intersections were upgraded to LEDs by 2006. In Wisconsin we historically have experienced approx. 2 snow events per year where conditions are just right to obscure signal heads.

3. Winter 2008/2009 A handful of Fortran’s Snow Sentrys were purchased in 2008 and installed at isolated intersections around the state. Photo is from a light snow event.

4. Winter 2010 WisDOT purchased and installed a handful of McCain’s Scoop Tunnel Visors and has installed them at the same intersections as the Snow Sentry installations so that we can do side by side comparison. Also purchased Intelight’s Automatic Lens Defrosters. McCain – Scoop Tunnel Visor Intelight – Automatic Lens Defroster