The ugly truth about what Marchetti’s Constant means for walkers almost everywhere.
Cesare Marchetti is an Italian physicist, an octogenarian who still lectures and researches from a post at the International Institute for Applied Systems Analysis in Austria. The original focus of his scholarship was energy – nuclear power in particular – but over the years his curiosity meandered. He started to look at humanity’s relationship with energy systems over time. He examined patterns of technological innovation, the way energy and food production systems interacted, millenium-long trends in transportation and banking and crime rates.
In 1994, in a paper that looks almost tangential on his CV, Marchetti uncovered one of those grand fundamental concepts that can turn an obscure scientist’s surname into a generic term.
The core of Marchetti’s seminal paper is an examination of "travel time budgets" through the ages (based on research first done by Yacov Zahavi in his fieldwork for the U.S. Department of Transportation and the World Bank in the late 1970s and early 1980s). Zahavi had found that regardless of culture, class, creed or access to advanced technology, the mean amount of time people all over the world spend in everyday transit is about an hour. The Japanese salaryman on the Shinkansen bullet train, the Amazonian hunter-gatherer, the Canadian suburbanite stuck in rush-hour traffic: all of them, left to their own devices (or lack thereof), will aim to spend about an hour commuting each day. Marchetti looked at the historical record and determined that the mean held true all the way back to neolithic cave sites. He refers to this as "the quintessential unity of traveling instincts around the world." In urban planning circles, it’s now called Marchetti’s Constant.
"Personal travel," writes Marchetti, "appears to be much more under the control of basic instincts than of economic drives." This might, he suggests, explain the “systemic mismatch between the results of cost-benefit analysis and the actual behavior of travellers." In other words, we’ve designed our transportation systems without any understanding of the most basic principle determining what makes us stop and go.
Marchetti is ecumenical when it comes to the means of transport (his own obsession, revealed in other papers, is with maglev trains), but all I could think about after reading his work was walking. For more than 10,000 years, Marchetti’s Constant has held sway over how we site our homes, do our day’s work and build communities. And for all but the last 100 or so years, virtually all of those hour-long daily commutes were made on foot. What would it be like, I wondered, to obey Marchetti’s Constant as a pedestrian in the modern city?
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Henry David Thoreau was one of the most ferocious critics of the industrial age. One of his most beloved essays is simply entitled "Walking," first delivered as a lecture at Massachusetts' Concord Lyceum in 1851. Thoreau detested cities, of course. Humanity’s urban "improvements" on nature, he wrote, were "tame and cheap."
Real walking, he believed, was a wilderness activity. In this, he foretold the pedestrian abandonment of city streets as the automobile ascended. Thoreau’s ode to foot travel yielded one of his most famous quotes:
[I]n Wildness is the preservation of the World. Every tree sends its fibers forth in search of the Wild. The cities import it at any price. Men plow and sail for it.
Here’s something, though, that might surprise Thoreau; it was certainly the most arresting lesson Marchetti’s Constant taught me. The cities have become Wildness. As we’ve radically retrofitted them for the car, spreading them out and out, carving half-paved chasms of emptiness between expressways and off-ramps and strip malls, a great unexplored Wildness has filled those spaces. We just don’t know about it because we never walk through it.
Inspired by Marchetti, I spent many days last fall walking through every urban landscape I had the time and opportunity to explore. I traversed welcoming prewar neighborhoods and suburban sprawl alike. I walked the perimeter of Old Montreal and the borderlands between the twin cities of Kitchener and Waterloo in southern Ontario. But my most memorable saunter with Marchetti began on the arrivals level of Terminal 1 at Pearson International Airport, in suburban Toronto.
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It was late November, an hour before dusk — just enough time to see how far the Constant could take me away from a vast transport-industrial complex that was only nominally less hostile to being exiled on foot than an actual prison.
As I walked the length of the terminal, I was inundated with transportation signs, but there was no exit marked for pedestrians. At the far end of the terminal, I simply walked out the last door and down a wide sidewalk until it ended in a raised concrete abutment. Back inside the terminal, I followed signs marked “Ground Transportation” to the level below. Again, the plaza-wide sidewalk narrowed and then ended in a low concrete barricade. Beyond, there was a thin strip of pavement barely wider than a curb between the retaining wall and the motorized traffic. I could see a rumor of a sidewalk as the exit ramp swooped up and away to my right. Feeling like a trespasser, I hurried up the thin strip to the paving stones ahead, the wheels of my suitcase crunching over gravel and wobbling behind me.
The walk from Pearson International Airport. (Chris Turner)
It’s difficult to explain how strange the sidewalk I discovered really was. It began in small, grey squares of interlocking brick, like a suburban patio, and it abutted the curb, so that you had to walk not even an arm’s length from the traffic passing rapidly by. The bricks soon gave way to cracked pavement, which ended in a blockade of scraggly undergrowth. The old pavement re-emerged a few rushed paces farther along. To get to the nearest thoroughfare, I had to walk alongside an access road for a quarter mile and then navigate a patchwork of paving stones representing at least four generations of sidewalk improvements.
This was vestigial pedestrian infrastructure. It must have been a trace memory scrawled across a handful of zoning bylaws and construction codes. You could easily imagine each project having been self-contained, the whole of it evidently never considered at all. It was untracked in its way, truly wild. It made sense only as a kind of symbolic gesture toward a past too distant to fully articulate its logic to the present day. I’m reasonably confident in saying that there’s no trail like it anywhere else on Earth. It was beautiful in its way, majestic in its carelessness.
I came eventually to the main road and followed it across yawning parking lots and past chain hotels to an underpass, wide and dark and forbidding. Eight lanes of traffic shrieked overhead. I marveled at how such scale and speed could seem so natural behind the wheel and so alien and reckless from the sidewalk below.
The road grew even more desert-like on the far side of the underpass. The off-ramps and outsized intersection were hemmed in by broad parking lots. The street-lights towered overhead like orphaned pines. As I waited for a light to change, I saw a bird come circling down over the highway to roost on top of one of the lamp posts. It was broad-winged and sharp-beaked, a bird of prey, a hawk of some sort. (If I was Thoreau, I’d have known exactly which species.) It perched there a long time, gazing over the highway and off-ramp, indifferent to the growling traffic. Its patience outlasted mine, and I carried on — across a viaduct that stretched over the fairways of a golf course, under a buzzing line of high-voltage wires that made the hair on my neck stand on end and finally to a strip mall with a warm, welcoming bar-and-grill sign.
Fifty minutes had passed since I left the airport. I was beyond Marchetti’s Constant, nowhere near my destination, lost in the automotive wilds. I was worn out and wide awake, tuned to this strange environment as never before. This was not the Wildness that Thoreau wrote about, but it was what he had in mind.