Like some others have said, you may hit a little traffic going through Sacramento (I used to live there for 3 years but my family is in So Cal so I made that trek often) and possibly a little when you hit Stockton (depending on the time of day) but after that it's usually pretty clear until you get over the grapevine and into Santa Clarita(that's where I live now). From then on it's unpredictable as to what the traffic will be like (again, it really depends on the time of day).