chains

[rplines at pacifier.com]

I was wondering the same last winter so I looked it up.  Here in Oregon, when chains
are required there is an exemption for certain vehicles.  You must meet all of the
following criteria: 
1. You must have power to all wheels.  
2. You may not be towing a trailer
3. The unloaded vehicle weight must be under 6500 lbs.
4. You must be carrying chains in the vehicle.
5. You must have "mud and snow" or "all-weather" tires (not necessarily studs) on
all four wheels.
6. You are not operating in an unsafe manner

This allows a quattro to breeze through without chaining up, however, point number
6 means you can be pulled over and required to chain at the officer's discretion.
 It's never happened to me so far...
Check your state Motor Vehicle Department or Dept. of Transportation for local laws.

-Peter