Dear Sweet Alice: What group of irrational, perverted, idiotic laws and/or bylaws govern the placement of DIP signs on our public roads? Can you inform me of the convoluted criteria consulted to determine which minuscule gradations of slope warrant recognition while invisible chasms of automobile death are conveniently ignored? Are our city officials receiving kickbacks from local body repair and alignment shops? — Jonathan “Shimmy&Shake” Goodwin, San Diego

Jon, my man, you’re taking this whole thing much too seriously. You seem to have visions of civil engineers with laser devices measuring every perturbation in the asphalt. Not even close, my friend. I can quote you chapter and verse on the damnable dips, but you still won’t know much more than you know now. To the folks who tend our city’s streets, a dip is a subjective concept.

According to the Traffic Manual, dip signs are installed “to give warning of a depression in a roadway sufficiently abrupt to cause discomfort to motorists or to cause shifting of the cargo or to deflect a vehicle from its course at normal driving speeds.” Lots of elbow room in those guidelines. Is the shifting cargo in a Geo or a semi? Exactly what qualifies as “discomfort to the motorist”? How far do you have to be “deflected” before the dip rates somebody’s attention?

Here’s how it goes. When you finally get tired of replacing mufflers torn out on whatever booby trap has inspired this question, call the city traffic folks (236-6040) and alert them to the situation. Eventually someone in that office will get in his or her car, actually drive over the offending chasm, and see if they think it’s sign-worthy. There, Jon, is chapter and verse on dip-sign technology. I can tell you that the cross gutters at intersections don’t really qualify as dips and so probably won’t be marked with signs since you’re supposed to be on the alert and perhaps moving more slowly as you enter an intersection anyway. And “normal driving speed” usually means whatever the street’s speed limit is. So now you’re as dip-knowledgeable as anybody in town.