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I feel confirmed my previous traction findings (http://www.cleanmpg.com/forums/showthread.php?t=17966) tonight.

For MY car with my Current tires:
Placard 32 - TOO low (for ANY conditions)
Tire mas 44 - Too high (for snow and ice)
someplace between 35 and 40 is best for snow and ice. :Banane49:

When I got on the freeway tonight lots of ice, traction not good. I could not bring myself to go over 45mph.

I exited the freeway as soon as I could and found a parking lot to check tire pressure. let some air out bringing the pressure down to 38. Re-entered the freeway, traction just fine now. ( traction as good as could be expected for the conditions)

In My Opinion: Max snow and ice traction = 1/2 way between placard and Sidewall max.

I find the same result. Pressing up well beyond 40psi on the snow tires leads to less traction on icy surfaces. But I find that for snow traction, pressure doesn't have as much of an effect. My car's placard is 32/32, sidewall is 44/44. When I had my snows mounted, it was 50F so I set them at 40 front/37 rear, which means roughly 38 front/35 rear at 30F. So I get the benefit of a bit more pressure above 32F when there is little chance of ice; and less pressure when icy roads are most slippery. And I use a bit less pressure on the rear to make them stick to a bit better and lessen the chance of the rear end sliding out on corners. To counteract the higher rolling resistance of winter tires and lower tire pressure, I just drive slower and less often.

These are similar to my findings from our big snowstorm last winter. 36-40psi seemed to give quite a bit better traction than 44-48psi. Agreed, no reason to go below 36 though. Since it doesn't snow here often, I'll keep my pressure in the upper 40s most of the time, and drop to upper 30s when snow is forecast or when driving to the mountains.