While searching for something else, I found this reminder I posted on last years planning forum:

As we approach the dates for the hang, one reminder to those driving:
Along some of the roads to the park, and especially the park roads themselves, can be very tricky, especially to those not used to driving on mountain roads, in the snow. The road in the sun can be dry, very dry. A few feet away, in the shade can be a VERY slippery sheet of ICE!! Many times this Ice can be in a curve.
So, a brief Primer for driving on the ice & snow, this is not all inclusive, but can be a start: Drive SMOOTHLY! Break SMOOTHLY! Do not accelerate or brake hard, in fact, do not let off the gas too fast. Turn INTO a spin. If your car doesn't have anti lock brakes, practice GENTLY pumping them to come to a stop if you slide. This should go without saying, but TURN OFF YOUR CELL PHONE WHILE DRIVING, Cause honestly, you don't need the distraction.
Consider turning off your radio (stereo, CD Player, MP3 player, etc) & having your passengers limit talking. The views along here can be heart stopping, if you MUST see one, find a place to pull over safely, stop, & THEN look!

I also posted:
For those still "On the fence" here is some Incentive for going: NO biting insects, Minimal chance of Hyperthermia, Fewer other hikers so solitude is likely to be easier to obtain, good possibility of snow, GREAT food at the potluck on Sat, & (Provided you packed properly) Great food the rest of the time The chance to fully test your cold weather gear.