There is a phenomenon of living in California that I'm not sure how many of my fellow residents share. And I'm not sure whether I just sort of picked it up from other friends when I first moved here, or whether someone specifically told me to be conscious of this. But - I have learned to be nervous on high overpasses and even moreso under overpasses, especially in slow or stopped traffic. Why? Earthquakes.
Statistically, its a silly fear. The earthquakes that I've felt since moving here eight years ago are few and very small (knock on wood). Maybe its time I re-stocked my earthquake kit.