So here you are, let us say, heading west toward the Caldecott at the end of a July afternoon. The geography, what with the hills rising on either side, pretty much requires you to focus on the thing that is about to happen in front of you — you can see it coming, and sometimes from quite a distance, depending on how bad the backup is. The trick about the Caldecott is that although each bore is two lanes wide, the middle bore switches direction, by means of signage and mechanically raised cone separators, contingent on the flow of the main morning and evening commute. So if you’re driving out of the suburbs toward Oakland at the end of the day, the cars coming the opposite way take that middle bore, which means your side of 24 is being coned off into the one remaining bore on the right — a four-lane to a two-lane funnel.

This is the point at which the North American driving populace, as you know, cleaves into two camps.

See also, for the transportation wonks, "The" Freeway in Southern California, which speculates on the origins of the regional practice of prepending "the" when referring to numbered freeways.