Grid plan
The
grid plan or
gridiron plan is a type of
city plan in which
streets run at
right angles to each other, forming a
grid.
The grid plan dates from antiquity; some of the earliest planned cities were built using grids.
By
2600 BC,
Mohenjo-daro and
Harappa of the
Indus Valley Civilization (in
Pakistan and
North India) were built with blocks divided by a grid of straight streets, laid out in perfect right angles, running north-south and east-west. Each block was subdivided by small lanes.
A workers' village at
Giza,
Egypt (2570-2500 BC), housed a rotating labor force and was laid out in blocks of long galleries separated by streets in a formal grid. Many pyramid-cult cities used a common orientation: a north-south axis from the royal palace and an east-west axis from the temple meeting at a central plaza where King and God merged and crossed.
Hammurabi (17th century BC) was a king of the
Babylonian Empire who made
Babylon one of the greatest metropolises in
antiquity. He rebuilt Babylon, building and restoring temples, city walls, public buildings, and building canals for irrigation. The streets of Babylon were wide and straight, intersected approximately at right angles, and were paved with bricks and
bitumen.
The tradition of grid plans is continuous in
China from the 15th century BC onward. Guidelines put into written form in the
Kaogong ji during the
Spring and Autumn Period (770-476 BC) stated: "a capital city should be square on plan. Three gates on each side of the perimeter lead into the nine main streets that crisscross the city and define its grid-pattern. And for its layout the city should have the Royal Court situated in the south, the Marketplace in the north, the Imperial Ancestral Temple in the east and the Altar to the Gods of Land and Grain in the west."
The first planned
Greek city was probably
Miletus, built after 479 BC. Its gridded design has been credited to
Hippodamus (although this may be apocryphal), a Greek intellectual associated with the
Pythagoreans. The grid plan was a common tool of
Roman city planning, based originally on its use in
military camps known as
castra. One of the most striking extant Roman grid patterns can be found in the ruins of
Timgad, in modern-day
Algeria. The Roman grid is characterized by a nearly perfectly
orthogonal layout of streets, all crossing each other at right angles, and by the presence of two main streets, set at right angles from each other and called the
cardo and the
decumanus.
Teotihuacan, near modern-day
Mexico City, is the largest ancient grid-plan site in the
Americas. By 150 AD, the city's grid covered eight square miles.
As
Japan and the
Korean peninsula became politically centralized in the 7th century AD, those societies adopted Chinese grid-planning principles in numerous locations. In Korea,
Gyeongju, the capital of
Unified Silla, and Sanggyong, the capital of
Balhae, adapted the
Tang Dynasty Chinese model. The ancient capitals of Japan, such as
Fujiwara-Kyô (694-710 AD),
Nara (Heijô-Kyô, 710-784 AD), and
Kyoto (Heian-Kyô, 794-1868 AD) also adapted from Tang's capital.
The grid-planning tradition in Asia continued through the beginning of the 20th century.
New
European towns were planned using grids beginning in the 12th century, most prodigiously in the
bastides of southern
France that were built during the 13th and 14th centuries. Medieval European new towns using grid plans were widespread, ranging from
Wales to the
Florentine region. Many were built on ancient grids originally established as Roman colonial outposts.
The Roman model was also used in Spanish fortification settlements during the
Reconquista of Ferdinand and Isabella. It was subsequently applied in the new cities established during the
Spanish colonization of the Americas, after the founding of
La Laguna (Canary Islands) in 1496. In 1573, King Phillip II of Spain compiled the
Laws of the Indies to guide the construction and administration of colonial communities. The Laws specified a square or rectangular central plaza with eight principal streets running from the plaza's corners. Hundreds of grid-plan communities throughout the Americas were established according to this pattern, echoing the practices of earlier Indian civilizations.
The grid plan became popular with the start of the
Renaissance in Northern Europe. In 1606, the newly founded city of
Mannheim in
Germany was the first Renaissance city laid out on the grid plan. Later came the New Town in
Edinburgh and almost the entire city centre of
Glasgow, and many
new towns and cities in
Australia, the
United States and
Canada.
Arguably the most famous grid plan in history is the plan for
New York City formulated in the
Commissioners' Plan of
1811, a visionary proposal by the state
legislature of
New York for the development of most of upper
Manhattan.
Often, some of the streets in a grid are numbered (First, Second, etc.), lettered, or arranged in alphabetical order. (
Washington, DC has examples of all three).
In the westward development of the
United States, the use of the grid plan was nearly universal in the construction of new towns. One of the largest advantages of the adoption of the grid plan was that it allowed the rapid
subdivision and
auction of a large parcel of land. For example, when the legislature of the
Republic of Texas decided in
1839 to move the capital to the new site along the
Colorado River, the functioning of the government required the rapid population of the town, which was named
Austin. Charged with the task,
Edwin Waller designed a fourteen block grid that fronted the river on 640 acres (exactly 1 square mile; about 2.6 sq km). After surveying the land, Waller organized the sale of 306 lots nearly immediately, and by the end of the year the entire Texas government had arrived by
oxcart at the new site.
The use of the grid on the American frontier was not, however, strictly functional. In the case of Austin, Waller designed a broad north-south thoroughfare,
Congress Avenue, that bisected the grid leading up from the river to the site where the new
Texas State Capitol was to be constructed. The main east-west thoroughfare was Pecan Street, later renamed
Sixth Street. The two thoroughfares have remained the primary arteries through downtown to this day, illustrating a successful adaptation of the Roman plan to the New World.
Ildefonso Cerdá defined a concept of urban planning, based on the grid, that he applied to the
Barcelona Eixample.
If one were to look at maps of larger American cities, it can be noted that the downtown areas are almost always grids, while the farther you get from the downtown the grid becomes less prevalent and the randomness of suburbia takes over.
In the United States, the grid system was widely used in most major cities and their
suburbs until the 1960s. However, during the 1920s, the rapid adoption of the
automobile caused a panic among
urban planners, who claimed that speeding cars would eventually kill tens of thousands of small children per year. They called for an inwardly focused "
superblock" arrangement that minimized through automobile traffic and discouraged it from traveling on anything but
arterial roads; traffic generators, such as apartment complexes and shops, would be restricted to the edges of the superblock, along the arterial. This paradigm prevailed between approximately 1930 and 1960, especially in
Los Angeles, where notable examples include
Leimert Park (an early example) and
Panorama City (a late-period one).
In the 1960s,
traffic engineers and urban planners abandoned the grid virtually wholesale in favor of a "
street hierarchy." This is a thoroughly "asymmetric" street arrangement in which a residential subdivisionis completely separated from the road network except for one or two connections to arterial roads. In a way, this is a return to
medieval styles: as noted in
Spiro Kostof's seminal history of
urban design,
The City Shaped, there is a strong resemblance between the street arrangements of modern American suburbs and those of medieval
Arab and
Moorish cities. In each case, the community unit at handisolates itself from the larger urban scene by using dead ends and
culs-de-sac.
*
City block*
United States -
Land Ordinance of 1785
