R3 is rare, the more common R2 means Sierra roads turn into parking lots so you won't be going anywhere.
The last I80 R2 Sierra crossing took me a bladder busting 4 hours to drive 40 miles.
+1. I've been doing the I80/HIWY50 runs into Tahoe for decades and have never seen an R3. I'm not saying they don't happen but if you happened to get in the middle of one you are in for the "ride" of your life. Chains don't work so well when you're stuck in the road.
I carry a set of old VW beetle chains when I go to satisfy the law but have never been asked to show proof.
