Grid plan: Wikis

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A simple grid plan road map (Windermere, Florida).

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. In the context of the culture of Ancient Greece, the grid plan is called Hippodamian plan.[1]

Contents

Ancient grid plans

The grid plan dates from antiquity and originated in multiple cultures; some of the earliest planned cities were built using grid plans.

By 2600 BC, Mohenjo-daro and Harappa, major cities of the Indus Valley Civilization, 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 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, which was rebuilt to a grid plan after 479 BC. Its gridded design has been credited to Hippodamus[1] (although this may be apocryphal), a Greek intellectual associated with the Pythagoreans. The pinnacle of Ionian grid planning however was Priene, set on very uneven ground and encompassing an acropolis. 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 AD 1500, the city's grid covered eight square miles.

Asia from the first millennium AD

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 (AD 694-710), Nara (Heijô-Kyô, AD 710-784), and Kyoto (Heian-Kyô, AD 794-1868) also adapted from Tang's capital. However, for reasons of defense, the planners of Tokyo eschewed the grid, opting instead for an irregular network of streets surrounding the Edo Castle grounds. In later periods, some parts of Tokyo were grid-planned.

The grid-planning tradition in Asia continued through the beginning of the 20th century.

Europe and its colonies

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 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 San Cristóbal de 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, Canada and the United States such as New Haven and Adelaide.

The baroque capital city of Malta, Valletta, dating back to the 16th Century, was built following a rigid grid plan of uniformly designed houses, dotted with palaces, churches and squares.

Early United States

Many of the earliest cities in the United States, such as Boston, did not start with a grid system.[2] However, even in the pre-revolutionary days some cities saw the benefits of such a layout. New Haven Colony, one of the earliest colonies in America, was designed with a tiny 9-square grid at its founding in 1638. On a grander scale, Philadelphia was designed on a rectilinear street grid in 1682; one of the first cities in North America to use a grid system.[1][3] At the urging of city founder William Penn, surveyor Thomas Holme designed a system of wide streets intersecting at right angles between the Schuylkill River to the west and Delaware River to the east, including five squares of dedicated parkland. Penn advertised this orderly design as a safeguard against overcrowding, fire, and disease, which plagued European cities. Holme drafted an ideal version of the grid[4], but alleyways sprouted within and between larger blocks as the city took shape. 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 Manhattan[5] above Houston Street.

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).[1]

In the westward development of the United States, the use of the grid plan was nearly universal in the construction of new towns, such as in Oklahoma City (1890), Salt Lake City (1870) and Dodge City (1872). In these western cities the streets were numbered even more carefully than in the east to suggest future prosperity and metropolitan status.[1]

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 km²). 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.

Late 19th century to the present

Ildefons Cerdà 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, mostly east of the Mississippi River, 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 subdivision—often surrounded by a noise wall or a security gate—is 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 hand—the clan or extended family in the Muslim world, the economically homogeneous subdivision in modern suburbia—isolates itself from the larger urban scene by using dead ends and culs-de-sac.

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Milton Keynes

One very famous use of the grid system was in the British new town of Milton Keynes. In this planned city, which began construction in 1967, a system of ten horizontal and eleven vertical roads at 1 km intervals was used with roundabouts at each intersection. The horizontal roads were all given names ending in 'way' and H or V numbers (for 'horizontal' or 'vertical eg H3 Monks Way). The vertical roads were given names ending in 'street' and V numbers (for vertical', e.g. V6 Grafton Street). Each grid road was spaced roughly one kilometre along from the next, forming squares of approximately one square kilometre. Each square and roundabout was given its own name. The system provided very easy transport within the city, although it confused visitors who were unfamiliar with the system. Note the 'grid squares thus formed are far larger than the city blocks described earlier, and the road layouts within the grid squares are generally 'organic' in form — matching the 'street hierarchy model described above

Benefits and criticisms

In a numbered grid system, adding an extra street can cause confusion

Financial cost

Grid street patterns are generally considered to be less expensive than a street hierarchy plan because fewer road miles are needed to serve the same population.

The pattern minimized disputes over lot boundaries and maximized the number of lots that could front a given street. John Randal said Manhattan's grid plan facilitated "buying, selling and improving real estate." [1]

Pedestrianism

Pedestrians have an easier time connecting to other parts of neighboring neighborhoods and commercial businesses. Obstacles such as culs-de-sac and busy intersections with high speed traffic that hinder or discourage pedestrianism are rarely present. The grid also enhances pedestrian access to mass transit.

Safety

Recent studies have found higher traffic fatality rates in outlying suburban areas than in central cities and inner suburbs with smaller blocks and more-connected street patterns.[6][7] While some of this disparity is the result of distance from emergency medical facilities (hospitals are usually built in a fairly late stage of the development of a suburban area), it is clear that the lower speeds encouraged by the frequency of intersections decrease the severity of accidents occurring on streets within a grid plan.

Stringent adherence to the grid plan can cause steep inclines since the topology of the land is not taken into account. This may be unsafe for drivers and pedestrians since it is more difficult to control speed and braking.

Reconstruction and development

One of the greatest difficulties with grid plans is their lack of specialisation, most of the important amenities being concentrated along the city's main arteries. Often grid plans are found in linear settlements, with a main street connecting between the perpendicular roads. However, this can be mitigated by allowing mixed use development so that destinations become closer to home. Many cities, especially in Latin America, still successfully retain their grid plans. Recently, planners in the United States and Canada have revisited the idea of reintroducing grid patterns to many cities and towns.

Addressing

House numbering can be tailored to the grid.

See also

External links

References

  1. ^ a b c d e f Jackson, Kenneth (1985). Crabgrass Frontier. Oxford University Press. pp. 73–76.  
  2. ^ Back Bay, Dorchester Heights, and South Boston all have grid layouts.
  3. ^ ExplorePaHistory.com
  4. ^ http://www.swarthmore.edu/Humanities/kjohnso1/pictures/tholme1683inch9.jpg Swarthmore College
  5. ^ Twelve Historical New York City Street and Transit Maps from 1860 to 1967 - John Landers – I SBN 1-882608-16X
  6. ^ http://www.minority.unc.edu:9014/sph/minconf/2004/materials/ewing.et al.pdf
  7. ^ http://www.virginia.edu/topnews/releases2002/lucy-april-30-2002.html

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