Louis Kahn Traffic Study
Louis I. Kahn, Traffic Study, Project, Philadelphia, Pennsylvania, Plan of Proposed Traffic Movement Pattern, 1952. From the Collections of the Museum of Modern Art, 389.1964.

A traffic study seems like an unlikely addition to the Museum of Modern Art’s collection of architecture-related items. But to understand why Louis Kahn’s 1952 ink, graphite, and decoupage traffic study for downtown Philadelphia became object number 389.1964 in MoMA’s archives, you have to remember that modern art is not a style at all. Rather, it’s an “attitude,” as some historians hold, about the impact of industry and mechanization on humanity. It’s modernity itself.

That sounds rather lofty. But when you consider the range of MoMA’s collection— from the prismatic fruit bowls of Post- Impressionism, to the fevered strokes of Abstract Expressionism, to the villanelles of sober Rationalism—you start to see that subject of modern art is always some ineffable spirit, even if the object created or the symbol depicted is something specific, prosaic, and tangible. A pipe (or not a pipe), the figure five in gold, a fractured nude descending stairs, or the physicality of paint or clay itself—all of these represent new ways of thinking about a rapidly changing world.

How does this relate to a traffic study? Architects and city planners have been intimately connected to the industry and mechanization that created most of what we see around us in our everyday lives; indeed, they were the chief authors of modernity itself more than half a century before Kahn’s birth in 1901. Nineteenth-century architects, planners, and city officials pursued a vision of urbanism based on City Beautiful principles— following Georges-Eugène Haussmann’s boulevards in Paris and Kaiser Franz Joseph’s incomparable Ringstraße in Vienna. Those urban experiments focused on notions of civility, simmering nationalism, new theories on sanitation, and what some observers have called “genteel beautification.”

As cities like Philadelphia continued to explode in both population and size in the early 20th century, many architects and planners turned to a rational approach to organize the chaos: The neat order of a household could be amplified to the order of a city. More people, more buildings, and then cars created a need to prioritize how neighborhoods could accommodate the daily crush of activity. Kahn created several traffic studies for Philadelphia in the early 1950s based on studies he undertook in the 1940s on how scale and order could work together. It’s also an interest he pursued throughout his entire career. (His AIA Gold Medal acceptance speech in 1971, “The Room, the Street, and Human Agreement,” delivered three years before his death, is widely held to be his definitive philosophy on architecture.)

Object number 389.1964 is a piece of yellow tracing paper, roughly 2 feet wide by 3.5 feet long, that shows the central business district of Philadelphia from the Schuylkill River to the Delaware River. On it, Kahn has mapped the staccato movement of buses and trucks as dotted lines, and the more fluid movement of cars as arrows joined end-to-end. Anchoring it all are a series of parking garages, depicted as spirals, that form a defensive perimeter for roughly 264 square blocks of homes, businesses, and public parks. Kahn’s idea was that the city is for people, and cars should be checked at the gates. The idea is a central part of Kahn lore: As medieval cities defended against ne’er-do-wells with brawny walls and bastions, our cities must defend against barbarous vehicles that threaten to flatten the ideal urban hierarchy into one unsustainable war between modernity and humanity. For the casual observer, the sketch can be read as a musical score or an inky cypher; it can even be read as a circuit board scheme. For Philadelphians, it can be read as the city that might have been, devised by an architect who never wanted to live anywhere else.