just for clarity, if it's snowing a lot on I-80, but not enough for them to close it down, CA-DOT will setup a tire check for
everyone to pass through. I've had that happen a few times with my Land Rover on the way to Tahoe. they are looking for the M&S and/or three-peak mountain symbols on the tires. that's when they'll ask about chains or snow socks if you're not in what they consider a 4x4.
usually when it's bad enough to
need chains on a true 4x4, they close it down anyway (been there for that too and had to wait it out).
I have a Gravity on order and it'll be interesting to see how CA-DOT treats them. My guess is they'll say you can't take that minivan up without chains.