It is written -- as posted before, there are 3 levels of "chain control":

R1 -- chains required except if you have "snow tires", which just means M+S marking common to "all season" tires; virtually all passenger vehicles get waived through this

R2 -- chains required except for 4wd with snow tires (M+S); any Subaru or 4wd SUV will get waived through this.

R3 -- chains required on all vehicles.

On the major highways like I-80, R3 is effectively never imposed that I'm aware of; the highway will be closed first, so those with 4wd SUVs really never have to use chains on those roads.

Be aware that technically, all vehicles, even 4wd with snow tires, are supposed to carry chains; I've never had them even ask but they could; I suspect the majority of 4wd drivers do not have them. (I've always read that as only when the "chain control area" is active, i.e. R-1 or higher during a storm, not that you have to have chains year-round to use the passes)

As mentioned, any storms especially that early are likely to be short-lived. Caltrans is very good about clearing the major roads, so if you have the flexibility to wait a half day or day worst case you should be fine.