# Chapter 1: The Permanent Framework What are cities made of? We tend to think of what we see: cars, people, buildings, shops, street signs, sidewalk cafes. These are the things we notice, the things that seem to define urban life. But beneath this churning surface lies something more fundamental and more permanent. Cities are not just their buildings, though we often think of them that way. Nor are cities just its people. Rome had a population of a million in the first century of the Common Era, but after the empire collapsed, that number plummeted to 60,000. The population didn't reach a million again until 1950. The buildings changed, the people changed, the entire civilization changed. Yet it was still Rome. So what persisted? What is the actual substance of a city that allows it to maintain its function across millennia? ## The Layers of Permanence To understand cities, we need to think like archaeologists, peeling back layers of time. At the surface, we find the most fleeting elements: paint colors, swing sets, stop signs, yard art. These things last months, years, maybe decades. Dig deeper and we find people. Individually, we last about 80 years. Collectively, our migration patterns can ebb and flow on similar timescales. Below that, buildings. A big-box store might last 15 years before it's torn down or vacated to ruin. A well-maintained house might make it 150 years. The average building splits the difference at about 80 years—interestingly, about the same as a human lifetime. Notice something important: all these elements (the ephemeral decorations, the people, the buildings) exist primarily in the realm of private property. They're owned by individuals or corporations, maintained by them, and when those owners move on or die, the maintenance often stops. It's hard for any individual to make something last beyond their own lifetime. But as we dig deeper into the city's archaeological layers, we begin to find elements that are publicly owned: bridges that span centuries, parks that have hosted generations of picnickers, monuments that have watched empires rise and fall. We collectively maintain these things, passing them from one generation to the next like civic heirlooms. And at the very bottom, in the deepest stratum, we find boundary lines. ## The Constitutional and Representational Orders Doug Allen, the Georgia Tech professor whose work inspired this book, described cities as having two orders: constitutional and representational. The constitutional order consists of the permanent framework—the streets, boundaries, public spaces, and monuments that endure for centuries or millennia. The representational order includes everything else—the buildings, businesses, people, and activities that animate the constitutional framework but change with each generation. Think of it this way: the constitutional order is the stage, and the representational order is the play. The actors, costumes, and scenery change with each performance, but the stage remains constant. This captures something essential about how cities work. At the foundation of this constitutional order lie boundary lines, the invisible legal demarcations that separate public from private, mine from yours. While life churns away at the surface, these lines persist at the foundational level for thousands of years. Take Imola, Italy. Two thousand years ago, Roman surveyors divided this territory into squares called *heredia* (from the same root as our word "hereditary"). The Romans understood they were creating something meant to be inherited, passed down through generations. And incredibly, it worked. Through the apex of the Roman Empire and its subsequent collapse, through medieval times when everyone retreated behind city walls, through the Renaissance, the industrial revolution, two world wars, and into our age of smartphones, those same boundary lines still guide Imola's growth today. ![[imola-italy.png]] You can't see boundary lines directly. They're legal abstractions. But over time, they become visible through their physical manifestations: fences spring up along them, buildings align to them, and most importantly, streets follow them. ## Streets as Inheritance Of all the elements in the constitutional order, streets are one of the most important. By streets, I don't mean just the asphalt or the traffic they carry. I mean the legal right-of-way, the publicly owned land between private properties. This distinction is crucial: the functions found within a right-of-way may change over time, but the legal boundaries of the street can persist for millennia. Streets possess two characteristics that give them remarkable staying power: First, they're collectively owned. Each member of the public has a stake in the streets. It's relatively easy for one person to tear down their own building, but try moving a street and you'll face the resistance of thousands. Every property owner depends on that street for access. Every business depends on it for customers. Every resident has adapted their life to its presence. The sheer inertia of collective ownership locks streets in place. Second, streets are inherited assets that improve over time. A street might begin as a rutted dirt path, but over generations it accumulates investments: gravel, then asphalt, then sidewalks, then street lamps, trees, underground utilities. Each generation inherits what the previous one built and adds their own improvements. Unlike private buildings which often deteriorate between owners, public streets tend to get better with age. This resilience is almost absolute. When London burned in 1666, the fire destroyed virtually every building. Christopher Wren, one of history's greatest architects, saw opportunity in the ashes. He proposed a new street plan with broad avenues radiating from grand squares, importing the latest ideas from Rome. But the old property lines reasserted themselves like a legal ghost. London rebuilt along its ancient streets. The same thing happened in San Francisco in 1906. Days before the earthquake and fire leveled the city, Daniel Burnham had delivered his visionary plan for new boulevards and civic centers. Here was the perfect chance to implement it as not a single building stood in the way. Yet when the smoke cleared, San Francisco rebuilt along its existing grid. The boundary lines had survived even when nothing else had. ![[san-francisco-fire.png]] ## The High Stakes of Getting It Right This permanence is both urbanism's blessing and its curse. When we get streets right, we create frameworks that can gracefully accommodate centuries of change. Manhattan's 1811 street grid has absorbed everything from horse carriages to skyscrapers, adapting to technologies and densities its creators never imagined. The commissioners thought it would take a thousand years to build out their plan; it took barely a century. Yet the grid they drew still works. But when we get streets wrong, we condemn generations to live with our mistakes. Every unnecessary curve that forces people to drive instead of walk compounds with superblocks that kill retail vitality and cul-de-sacs that destroy connectivity. These failings persist with the same stubborn permanence as successes. The commissioners who laid out Manhattan made one critical error: they didn't include alleys. It probably seemed like a small decision at the time. But for over 200 years now, every single day, New Yorkers and tourists alike must navigate sidewalks piled with garbage bags. Millions upon millions of people, over centuries, dealing with the consequences of one decision. The cost to fix it now—buying thin slivers of valuable property to create rear service alleys—would run into the billions. So the garbage remains. This is deep time planning. When we draw street lines, we're not just organizing space for current residents. We're creating the framework that will shape lives for centuries, possibly millennia. Those lines will outlive the planner, the client, the civilization that drew them. They'll persist through technological revolutions we can't imagine and social changes we can't foresee. ![[Urbanism Layers Diagram.png]] ## The Lost Art Given these stakes, you might assume that modern city planning would focus obsessively on getting streets right. But that's not what happened. Somewhere in the early 20th century, the careful art of laying out streets—what was once considered the very foundation of city planning—got buried under zoning codes and traffic engineering standards. We started designing cities backward, focusing on land use (what goes where) instead of the permanent framework (the streets and blocks that will outlast any particular use). We prioritized separating things (houses from shops, offices from restaurants) without first ensuring we had a framework that could gracefully accommodate any of these uses as they inevitably shift and change. Frederick Law Olmsted, the legendary landscape architect, put it simply: *"The street plan [is] the foundation of all city planning."* Yet today, many planners have never learned (or have set aside) these fundamental insights. Streets have been reduced to mere traffic sewers, their deeper purpose as the permanent framework of cities largely ignored. This book is about recovering that lost knowledge. It's about understanding why the street plan must come first, before zoning, before architectural guidelines, before economic development strategies. Because unlike buildings, unlike businesses, unlike even the people who inhabit them, streets are, for all practical purposes, permanent. We'd better get them right. *** Continue to [[Chapter 2 - What is a Master Street Plan]] →