Reviewing the three CalTrans chain requirements:
- R1: Chains or "M+S" (mud and snow, though some tires with that marking aren't suitable for either)
- R2: 4WD OR AWD With M+S or Chains
- R3: Chains
R3 is extremely rare - it is far more likely that before the conditions get to R3 buttheads will crash into each other, blocking plows from getting through and allowing snow to pile up, thereby closing the road. I've driven extensively in Tahoe area snow, never driven R3 (did put chains on a AWD once on a residential street), and heard an R3 report once (CA-267 to Tahoe when CA-89 to Tahoe wasa closed due to avalanche).
That said, I've owned Subarus (AWD) since 1997. I've always carried chains, never had a police officer ask to see them, but I have a friend who was asked about chains for his 4WD Jeep Grand Cherokee when he slid on ice and went into a snowbank. So...the law requiring one to carry chains even with 4WD/AWD can be enforced.
As a visitor, though, in November (which is really the beginning of the wet season - December through March is the height), I wouldn't bother reserving 4WD. Get chains if weather threatens, if you're driving up US-395 to Tahoe get them in Bishop, if you're going up CA-41 to Yosemite get them in Fresno. If you arrive with lots of really bad weather threatening and 4WD/AWD is available for rent then just pay the extra cost and treat it as an unexpected and unlikely added cost.
Edited 1 time(s). Last edit at 10/29/2013 07:06PM by ttilley.