Permanence
What are cities made of? Think on this for a second and picture yourself walking or driving around. What do you see? Cars, dumpsters, people, trees, signs, sidewalks, ice-cream shops, shoe stores, hospitals, schools, libraries, skyscrapers, houses, apartments, etc. Cities are mankind’s largest built work. Consider that each of the components just mentioned experience some level of change, at some rate, resulting in a life expectancy[^This concept of life expectancy is addressed by Brenda Scheer in "The Anatomy of Sprawl", Places Volume 14, Issue 2.]. The average big-box retail building, for example, is built to last only 10, 15, or 20 years. Interestingly, humans, street trees, and the average building[^There is a lot of spread in this number. The average residential building lasts about 150 years, but the average big-box or low-quality apartment complex lasts about 20 years. The overall average for all buildings is roughly 80 years.] share comparable life expectancies of roughly 80 years. But what is the element of the city that lasts the longest? The street.
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| City Component | Life Expectancy (years) |
|---|---|
| Car | 20 |
| Dumpster | 20 |
| Building (Big-Box Retail) | 20 |
| Street Tree | 80 |
| People | 80 |
| Building (Average) | 80 |
| Building (House) | 150 |
| Street Rights-of-Way | 1,000s |
Streets (i.e., the boundary lines, rights-of-way) can survive on the order of thousands of years. An example of this is illustrated in Imola, Italy. Imola was founded by the ancient Romans about 2,000 years ago. When they subdivided their territory, they used a unit called a heredium which is 240 feet on a side. The word heredium shares a similar root to the English word hereditary. The idea was that a family would continue to pass on and inherit these heredia over time. Now imagine this taking place over a 2,000 year period, with the apex of the Roman Empire and then its subsequent decline, when everyone retreated behind the walls of their medieval cities, and then reemerged during the Renaissance, and then sparked the industrial revolution, and then had a couple of World Wars, and now everyone is walking around with iPhones. Even under the pressure of immense change experienced over that span of two thousand years, those heredia are still guiding the growth of Imola today.
The boundary lines that were established by the ancient Romans two thousand years ago have subsequently been translated into farming lots, fences, building walls, streets[^"Street" is being referred to here not just as the asphalt, or the thing one drives on. Rather, the legal definition of "street" is a public right-of-way with its boundary lines that distinguish between public property and private property. The whole cross section of the right-of-way is the street: from property line to property line].
Streets, then, form part of the "constitutional order" of cities: together with boundary lines, public places (including parks and buildings), and monuments, they are a part of the permanent framework of urbanism. The remainder, the "representational order", makes up the stuff we see day to day: cars, people, and private buildings, etc. These elements animate the constitutional order and give it meaning, but they are fleeting relative to the permanency of the constitutional order.
Resilience
How do streets survive such long time scales? Where do they get their resiliency?
First, public streets are collectively owned. Each member of the public has a stake in its streets. It’s relatively easy for one person to coerce a few people into doing something, but it’s a lot harder for one person to coerce a few thousand or million people. A street cannot simply be moved from here to there without having to get potentially millions of people to buy into such a move. Additionally, the legal network that makes up the foundation of property ownership is a function of the location of streets. Where does a setback proceed from? The street. How does one enter their house? From the street. Streets are collectively owned and through the nature of the resultant property ownership become locked into place.
Second, streets are simply inherited assets. They are handed down from generation to generation. They are excellent receptors of investments made over time: one could start with a rutted-out dirt road, and then add some gravel, and then twenty years later add some asphalt, and twenty years later add some sidewalks, and then street lamps and street trees, and so on. As a public asset, they can be improved upon over many generations.
It is because of these two reasons that streets have survived incredible catastrophes through history. For example, the Great Fire in London in 1666 completely destroyed the city. Christopher Wren, one of the greatest architects of all time, tried to take advantage of the situation, seeing it as an opportunity to introduce new avenues (in the same fashion as Rome at the time) to London’s dense, cranky street network. But because of the legal ownership patterns, the city’s urban form largely reemerged from the ashes as it was before the fire. There was an urgency to rebuild, and that urgency outweighed the complexities of reconfiguring property lines.
In San Francisco in 1906, a catastrophic earthquake was followed by an even more catastrophic fire that ultimately leveled the entire city. The scenes of the destruction are striking, presenting a wasted landscape denuded of life. Similar to the case of London, Daniel Burnham (an influential American architect and planner) had spent the previous year before the earthquake reimagining the city’s urban form. As a prelude to the 1909 Plan of Chicago, Burnham’s plan for San Francisco had envisioned new avenues and thoroughfares, civic centers, and parks. Burnham delivered the plan to the city only a few days before the earthquake hit. And one would have thought the fire presented an incredible opportunity to implement the plan. However, similar to London, the grid of San Francisco resisted both fire and planner. San Francisco’s urban form today is largely unaltered from its pre-1906 configuration.
Benefits
What do streets do for a city? What do they do for us?
In today’s auto-oriented landscape, the most obvious thing streets do is connect people. Whether one lives in Atlanta, Agra, Paris, or Kuwait City, streets are the medium for getting around. They are driven on, biked on, and walked on. They get people and goods from point ‘A’ to point ‘B’.
But they require much more appreciation than this. Streets are not just for transportation. Just as importantly (if not more important), they provide access to property and they create frontage. When someone goes to Paris and marvels at the city’s monuments and architecture, they are seeing Paris primarily through its streets. The face of Paris is made up of the buildings that front the street, it is how Paris presents itself to the world. The lesson here is that the more streets a city has, the more street frontage it has, which means more front doors, more front yards, and more storefronts. More streets means more opportunities to open up a city to development, to produce these vibrant neighborhoods common in the great cities of the world.
Streets also help to subdivide land into developable and accessible units. There are some dimensions of streets that do this better than others. For example, take a block that happens to be 280 feet by 520 feet on a side. In Chicago, a block of that size accommodates condo buildings, and townhouses, and some bungalows. In Amsterdam, the exact same block accommodates townhouses and a palace. In Buenos Ares, the exact same block accommodates apartments and a market. That block could also be used to accommodate a grocery store and its parking. Or a Super Walmart. How can the exact same block accommodate all these things, all these different cultures, different languages, different building types, different land uses? This kind of flexibility is an amazing characteristic of good urban form, and it is one that is measurable and useable. As was already discussed earlier in the Introduction, the vast majority of what is built in the world—houses, shops, skyscrapers—are all based on the same dimensional DNA.
Additionally, streets can contain public utilities. As public spaces, this makes sense. David McCauley, author and illustrator, developed a wonderful book called Underground with beautiful drawings where he peels back the asphalt of New York streets to reveal what happens underneath. You would be amazed at what all we have shoved underneath our streets.
Finally, streets are a city’s largest public space. Portland, Oregon, for example, has small blocks, 200 feet on a side. With typical right-of-way widths of 60 feet, the percentage of land in Portland that is allocated over to streets is 40%. That’s almost half, by the way.
Over time and around the world, there have been numerous planners who have recognized the street’s critical nature in cities. Edward Basset, one of the founding fathers of American planning and author of the 1916 Zoning Resolution in New York, said:
A civilized community needs streets for sewers, water supply, gas and electricity. This relates to the public health and comfort. It needs streets for water for fire protection and the movement of fire apparatus. This relates to public safety. It needs streets for foot and wheel traffic. This relates to all police power fundamentals.
Frederick Law Olmsted, celebrated American landscape architect:
The street plan has always been regarded as the foundation of all city planning.[^Address before the Second National Conference on City Planning, 1910.]
Otto Wagner in Vienna, one of the greatest architects in history:
Streets and squares demand the greatest care and attention in the planning of a city. They need to be discussed first.[^From Wagner’s book Modern Architecture, 1902.]
And Doug Allen, one of the greatest visionaries in planning since Kevin Lynch:
Streets are the primary structural unit of the city.[^From Doug Allen’s "The History of Urban Form," Lecture 01, delivered 2013.]
We find ourselves today, however, in a situation where city planners have either forgotten, chosen to forget, or never even had a chance to learn these insights. Because of this, many of the streets built since the middle of the 20th century were put in place specifically for the movement of traffic and excluded all the other important functions and qualities of streets just mentioned. It is no wonder that the places that have been built around these one-dimensional, single-use "traffic sewers" are equally as one dimensional and single use. The character of the street directly affects the character of a place. We will explore the repercussions of this and provide a fuller history in a subsequent chapter titled The Enabling Acts, but for now we will focus on the most important planning device ever conceived, one that has been largely lost for 100 years but holds the key, we believe, to building cities that are more walkable, sustainable, and enjoyable: the master street plan.