Wish I had seen this thread eariler. In my previous work life in interfaced with CHP several times each winter regarding the chain conditions on I-80 over Donner Summit, and frequently talked to the CalTrans guy who actually made the call on what the chain control level was and where. While I am not 100% certain it would be the same in the Big Bear area (the north state decisions are made in Marysville, not sure what command Big Bear falls under), you will likely never have to worry about R1 controls. In almost all circumstances if the conditions get worse than R2, they close the highways. I worked directly with them every winter for almost 10 years and never saw R1 controls ever. Almost all chain installers etc who work in the snow all the time only have 4X4 with snow tires because if the plows can't keep up, CalTrans pulls the plug. Again, your area may be different, but I would guess CalTrans has the same guidelines statewide.

It is a California thing due to the funky (read:dumb) liability laws here. Can you imagine if they closed the east coast when it snowed bad?