Improving US 101 in NorCal (split from Least Favorite Fwy in NorCal thread)

[kkt]

How often does 101 close due to snow?  I realize it'll vary, but is it every year?  Most years?  Several days a year?

I'm thinking that putting the bypass partway up the ridge was a good idea, if it's safer and faster 364 days/year, even if during the other 1 day a year traffic must detour to the old 101 route.