The US-101 between San Francisco and the North Bay is one of the most traveled roads in Northern California. It is the only real main artery connecting San Francisco and the Northern Counties. As such, you can imagine that the traffic is extremely heavy especially in either morning or evening "rush" hour commutes. Please plan your trip accordingly.
Roadwork is also common along the US-101 and it will frequently be a nuisance for the traveler however we must understand that because this road is heavily traveled, it also needs more frequent repair.
Be careful of the areas just North of the Golden Gate Bridge, these are areas that travel through the beautiful mountains and frequently have fog roll in and also the gusts of higher winds can surprise you quickly and you need to aware of them so your reaction time is better.
Not to really beat a dead horse, but be careful on this road because road and traffic conditions change very quickly. While this is not a road that we actually enjoy for the scenery, it is one of the most direct routes up to the North Bay area so that you can come and enjoy some of the most beautiful country in the U.S.