We often use the utilitarian, rational deployment of street grids as a boon to our best cities. American cities like New York, Philadelphia and Washington D.C. stand as the result of a preplanned order deployed to guide expansion over time. In many ways it has worked. Partitioning up the city has helped to shape a straightforward process for development, creating defined districts for zoning along with a web for transportation. But as the way we interact with the city evolves, including the buildings within it, the grid lags behind, representing the same functions that it did centuries ago. These massive infrastructural frameworks have grown to the point of being outmoded, trailing the urban evolution around and within them. We are at a point for a reassessment for how best to use this wealth of connective tissue that provides access to and from our homes, our jobs and our leisure both inside and outside of the city. more

As it recently reached its 200th birthday, New York's street grid provides a prime case study for weighing how we utilize a network of systems that we have come to simply accept as a constant (for any system that should be the first clue that a fresh look is warranted).

Manhattan's grid covers roughly 25% of its ground plane making it one of the city's largest infrastructural assets. Originally, the plan was the brainchild of Gouverneur Morris, Jon Rutherfurd and Simeon De Witt: a three member commission assigned by the New York State Legislature to create a plan for the island. The plan, by and large similar to the latticework of streets we know today (though missing Central Park), was proposed in 1807 and finally adopted in 1811. The "New York city block" was born.

Far before the days of fiber optic and coaxial cable, the grid also provided unfettered access to surface transportation throughout the island with roads that could reach the entire landscape in a straightforward way that was easy to navigate. Its wide streets allowed for a fluid transition to the advent of street cars and when the dawn of the automotive era demanded more real estate, elevated trains and subways followed. Throughout the past 200 years the grid has facilitated the movement of billions of people. However, the rational perfection of the street grid is largely to blame for its success in providing such universal access to transportation, though possibly at the expense of pedestrian mobility.

The Good Old Grid

A walk down the street today reveals that little has changed. Cobblestones, granite and gas lamps have given way to asphalt, metal curbs and street lights, but in essence the grid operates the same as always. The city that it defines, however, is bigger, denser and faster than it was when the grid was first deployed. At the time of its inception, the utility of the grid was a vision of a city beyond imagination that pulled its development through centuries of urban evolution. With all of its blocks now filled, the grid has reached the planar capacity of its designers, yet while the city has evolved the utility of the grid has stalled, locked in a preference of automobile infrastructure.

At one point in our history this made a lot of sense, embracing a new degree of mobility that connected us with intracity and intercity travel, but as the city has reached higher degrees of population density it becomes clearer that it is people, not cars, that constitute the lifeblood of the cityscape. While tall towers may facilitate the proximity of increasingly large numbers of residents and visitors, the urban experience of mixing and interface still occurs at grade. With parking a commodity in short supply it is pedestrians that provide patronage for stores, street vendors, restaurants, theatres, galleries and museums. The Bloomberg Administration's PlaNYC notes that, "Most New Yorkers are pedestrians at some point in their day–whether walking to school, to the corner store or to the subway. A safe and accessible pedestrian realm is a building block of a sustainable transportation system."

The residual 20th century distribution of ground plane into either/or pedestrian/car levies a social and environmental tax on the cityscape with minimal benefit. The hazards to pedestrian safety coupled with a system anchored in carbon emissions do not facilitate people walking up and down the streets. Inherently anti-urban in its programmatic and spatial preference of vehicular transit, the grid remains an outmoded form of infrastructure.

The Waning Reign of Cars

Right now, the streetscape is essentially an environment for cars with pedestrian access, rather than the other way around. If pedestrians and their ability to move around the city carries so much value, then why do cars get such a disproportionate amount of the ground plane for transportation? A recent proposal by designer Shelby Doyle and myself offers some preliminary thoughts on what options would be available for the square footage currently assumed by car travel.

As the city hosts a population of new societal and cultural norms it is faced with the bold realities of a digital interconnection, saturation of public space, a changing climate and the need for resiliency. In the wake of Hurricane Sandy is becoming clear that the grid must evolve to support new, resilient infrastructure to protect the value of Manhattan's assets in the built environment. This could be in the form of stormwater mitigation like green or blue roofs, waterproof utility lines or coastal wetlands–all supporting more storm resilient buildings.

This design highlights a series of possible uses, each with different relationships between people, buildings and existing infrastructure. With an implementation starting on Broadway, the spatial spine of the city, these insertions could grow over time as the city transitioned into new utilization of its own space. This move could liberate the grid from the sectional constraints of auto travel, allowing a new, imaginative urban landscape of hills, pools, bicycle highways, advanced public transit, internet infrastructure, food lifecycle programs and uses which challenge the pavement / park dichotomy of the current city. The purpose of the proposal is not to prescribe what the grid should be, but spark some conversations around all that it could be instead of miles of asphalt.

The grid could evolve with new priorities that create a very different urban experience

The Opportunity Costs of Cars

The excessive amounts of square footage devoted to vehicular movement not only constricts the space we can devote to pedestrians, but is the source of recurring liabilities for the city at large. Pavement is expensive to maintain and faster to degrade in quality than sidewalks given their constant abuse. The city spends tens of millions of dollars a year on repairing its road network, still leaving a quarter of its road surface at less than "good" condition as of 2011 according to PlanNYC.

Additionally, Manhattan has over 103,000 licensed off-street parking spaces in lots and garages. An average space is designed to roughly 9'-0" x 23'-0", or 207 square feet, resulting in at least 21,321,000 square feet devoted to parking (in a garage setting, the average is likely closer to 300 square feet per car, nearly 710 acres.)

Let's not forget the carbon weight that vehicular travel levies on cities as well. Beyond the clearest cost of burning gasoline and its resulting effects on emissions and air quality, the roads that facilitate car travel are a prime contributor to the urban heat islands. Throughout the day rooftops and roadways absorb enough of the sun's light that it can increase the local temperatures up to 10 degrees compared to locations outside of the city. The effect can actually be its worst not during the day, but at night when the thermal mass of the built environment radiates back into the air.

As ambient air temperatures rise, the work of our now-common air conditioning systems goes up in kind, further taxing the electrical grid behind them (both of which incidentally only add more heat to local environment). Aside from a decrease in efficiency and a rise in energy use, the sacrifices are felt by the urban microclimate where species of plants and animals alike fail to cope with excessive heat.

The dangers or congested streets dominated by motor vehicles carry other costs even more dire. Streetsblog reported that according to the NYPD over 15,000 pedestrians and cyclists were injured in New York City traffic in 2012, and 155 were killed. The year saw 198,361 auto crashes  reported citywide. In the currencies of both dollars and human health, these costs are extremely high for a service that does relatively little to increase activity on each side of the street.

Changing it Up

While cities may represent the most sustainable development pattern that we have due to their high population densities, the street grid itself has the opportunity to be a much more sustainable component to the greater system than its current likeness.  The priority that the grid grants to cars only encourages their continued participation into the urban realm. City-mandated parking minimums continue to add vehicular capacity to new buildings while the ease of moving around the city by car continue to make parking lots–a program type that functions as a hole in the urban fabric for pedestrians, adding virtually nothing to the streetscape–a financially attractive option for landowners instead of development.

The transition of the grid can serve as a catalyst for future evolution of systems intervention and how we use the city as residents, visitors and business owners. We can find new ways of moving goods in and out of the city. We can condense swifter transportation methods into smaller portions of a space largely commanded by pedestrian traffic. As cities grow to the point of self-sustenance due to population design, a large percentage of its acreage can be returned to its citizens in the form of systems that take infrastructure beyond the utilitarian status quo into a new social and environmental vision.

[The design proposal was created by Shelby Doyle & Tyler Caine. The designers retain rights to all imagery]

Image Credits: Intercon,theatlanticcities.com