[toast0]

Through the peninsula, especially in mountain view, it runs from southeast to northwest, north is towards the bay; south is towards the mountains. ca-85 is much closer to north/south through mountain view.

[DrScump]

... until it's East/West from Saratoga on.

It gets more fun in the East Bay: you can be going Eastbound on 580 and Westbound on 80 at the same time (it's a shared road)!