Can you solve a mystery for us? Why is it that every so often as you’re driving along there’s just one shoe lying there on the road? There’s never the other shoe in the pair, just that one shoe. Does someone throw their shoe out the window in disgust? Do kids throw their parents’ shoes out the back of the station wagon? Do they sprout from seeds sewn by bird droppings in the pavement? This is a worldwide phenomenon: I’ve seen road shoes sit there, dusty and flattened, in India, Europe, and Mexico and on many highways and byways of North America. Any advice will be appreciated. –Emily Baumbach, San Rafael, California

Well, we can nix the sprout-from-seeds hypothesis right off the bat. You’re undoubtedly thinking of shoe trees (guffaw). OK, got that out of my system. Many great and not-so-great minds have wrestled with this phenomenon without arriving at any firm conclusions. I note, for instance, that my fellow investigator David Feldman devotes seven pages to the topic in his book When Do Fish Sleep, in the course of which he elucidates 13 theories on lone shoe origin. Clearly, what Dave needs is to meet a nice girl. It is high time I settled matters once and for all.

First a few observations from the field. As usual in the case of your more inscrutable questions, Cecil and his minions have been prospecting for tips on the radio. So far we have come up with the following:

Peak shoe spotting season is summer through fall.

There is disagreement on how widespread the phenomenon is. Contrary to your report, some say it’s confined to North America, and that you never see shoes on, say, the German autobahn.

There is no single explanation for the lone shoes. We heard from a variety of people who’d lost shoes over the years. One woman had placed an extra pair of shoes on the roof of the car while she loaded some stuff, then forgot about them and pulled off. When she checked a while later they were gone. Another said a passenger had his feet up on the dash when the car hit a pothole, whereupon he became unshoed. Unshod. You know what I mean. Yet another claimed he personally had gone around the country strategically depositing shoes in order to sow panic amongst the populace. There’s one in every crowd.

None of this really gets at the heart of the matter, however. Cecil and his dedicated research team, including two short and irrepressible members who several times came perilously close to contributing personally to the lost shoe population, recently conducted a 1,500-mile cross-country car trip, traveling on everything from interstates to gravel roads. En route we passed thousands of identifiable items of roadside debris, chiefly pieces of retread tire on the interstates (how anybody can stand to drive on those things I will never know) and food packaging (mostly cans and bottles) everywhere else. Total shoe count: four, including one each in Knoxville, Tennessee, and Louisville, Kentucky, and two on the road into Chicago.

Granted this was in May, not (to hear some tell it) the height of shoe season. And I probably missed a few, such as when one of the little researchers was screaming at the top of her lungs. Still, considering the vast quantity of roadside crap, we are talking about a tiny number of shoes.

I would venture to say people have the idea that the highways are littered with shoes simply because (1) a roadside shoe is an ineffably memorable sight, lending itself to many rude jokes about what the owner was doing or having done to him/her at the point of loss, and (2) virtually all other trash on the road is either anonymous or numbingly commonplace. As to why you always see one shoe, never a pair, what do you expect? Assuming most of the shoes are lost by accident, the chances of two randomly ejected shoes landing together is vanishingly small. So there you have it. I have staked out my theoretical position, backed by the power of empirical observation. Take me on if you dare.

Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.

Cecil Adams is the world’s most intelligent human being. We know this because: (1) he knows everything, and (2) he is never wrong. For more, see The Straight Dope website and FAQ.