Answering questions about 'snow tires'

snow tires What makes a tire a "snow tire?" Are your tires suitable for driving through snow, or do you need to replace them?
   Not necessarily, according to David Dye, Chief Maintenance Engineer for the Washington State Department of Transportation (WSDOT).
   To clear up confusion about "snow tires," WSDOT and the Washington State Patrol have agreed to refer to such tires as "approved traction tires." Such a change will be reflected on mountain pass highway signs and on WSDOT's Mountain Pass Road Report.
   Approved traction tires are defined as having at least an eighth of an inch of tread depth, and are labeled "Mud and Snow," "M+S" or "M/S" on the sidewalls. Many of these tires are used all year. Studded tires also qualify as approved traction tires.
   Highway signs and advisories now read "Approved Traction Tires Advised" or "Approved Traction Tires Required," depending on weather and road conditions. WSDOT reminds motorists that studded tires are legal now through March 31, 1996.