Lakhasly

The streets system, encompassing avenues and boulevards, is fundamental to experiencing and understanding a city, defining blocks and distinguishing public, accessible spaces from private or semi-public areas. Streets serve as the public, democratic space where diverse citizens interact. Bill Hillier, founder of Space Syntax, argues that streets do not merely reflect societal divisions but can gather in space what society insists on dividing, considering their livability a key indicator of a strong civil society. In morphological and temporal terms, the streets system is the most stable element of urban form, offering greater resistance to urban transformation than plots or buildings, which have lesser durability over time.

Streets vary widely in shape, size, relationships with surroundings, and urban functions. A street's character is significantly influenced by other elements of urban form. These include the plots on either side; the buildings themselves, their height, and the ratio of height to street width; how buildings are sited on plots (e.g., near frontage for enclosure or set back for openness); and the entrances buildings offer. The distribution of space for pedestrians and vehicles—public or private, motorized or non-motorized—is also a crucial analytical aspect, as noted in works like Allan Jacobs' "Great Streets."

Diverse examples illustrate this variety. New York City features Broadway, unique for its irregular pattern within Manhattan's orthogonal grid, and the prominent 5th Avenue (10 km long, 30 m wide). Paris's Avenue des Champs Elysées, a symbol of Baron Haussmann's 19th-century intervention, is a grand axis (2 km long, 70 m wide in its western part) with homogeneous buildings, where building height is clearly inferior to street width, creating a strong sense of openness. It boasts a strong presence of trees and varied functions like shops, cafes, and cinemas, forming part of a longer axis linking La Defense and the Louvre. Siena's Via Rinaldini, a small medieval street less than 50m long and 5m wide, is directly linked to the city's famous square, notable for buildings whose height is clearly higher than the street width. Amsterdam's Reguliersgracht, part of the 'ring of canals' from the 17th century, has a unique cross-section (30 m wide, 600 m long) that includes a canal and, on each side, a street with distinct spaces for pedestrians, vehicular traffic, and car parking.

The public spaces system of a city extends beyond streets for movement to include open spaces for permanence, such as squares and gardens, which also exhibit significant diversity in form and function. New York's Times Square, located at the intersection of Broadway and 7th Avenue, is morphologically an intersection yet is consistently bustling with people, serving as the heart of the Theater District with numerous cultural and commercial activities, accentuated by attractive neon lights, and famed for its New Year’s Eve celebration. Paris's Place Georges Pompidou (175 m long, 70 m wide) has a clearly defined rectangular shape and a distinctive sloping surface that invites diverse activities and establishes a strong artistic dimension due to the Centre Georges Pompidou. The nearby Place Igor Stravinsky complements it with modern sculptures. Siena's Piazza del Campo, a 12th-century Italian square, is famous for its shell shape and wide sloping surface, delimited by notable palazzi of varying heights, with its lowest point at the town hall; it hosts events like the Palio horse race. Meidan Emam in Isfahan, Iran, is a grand rectangular square (520 m long, 160 m wide), bordered by a continuous two-story building volume with a double colonnade. It includes UNESCO-classified mosques and a palace, provides access to the Bazaar, and is intensively used by local people for many activities, distinct from the other examples due to a lesser presence of foreign tourists.

The diversity seen in streets is mirrored in squares, even within the same city. Paris's Place Vendome, an early 18th-century square in the Tuileries area, is rectangular with octagonal corners (140 m long, 120 m wide). It is crossed by only one street and is composed of architecturally homogeneous buildings housing fashionable shops, illustrating how urban fabrics vary significantly within a single metropolis.

The Streets System It is through the streets system (in the generic sense, including avenues, boulevards…) that we travel, and start to know, a city. Streets define the different street blocks that constitute a city and distinguish what is public, and is therefore accessible to all citizens, from what is private or semi-public. Streets are, in broad terms, the public and democratic space of the city, the place where we all met, with all our differences, and where we all interact in social terms. All these possibilities of interaction are restricted when we move from the streets to the interior of buildings. Bill Hillier, the founder of Space Syntax, recently wrote, in a paper submitted to the International Space Syntax Symposium (ISSS), that social differences have no expression on streets. This British author argues that streets ‘do not reflect the society’ (or the most negative aspects of society),

and that, on the contrary, streets can gather in space what society insists in dividing. In addition, Hillier argues that the livability of the streets is probably the most relevant indicator of the presence of a strong civil society (Hillier 2009). In morphological terms, and in a temporal perspective, streets are the most stable element of urban form. While the physical process of city building is something that ‘takes time’ involving permanent transformation—it has a past, a present and a future—the streets system of a city is the one that offers greater resistance to this process of urban transformation, attaining a great temporal stability. The plots system has a lesser durability than the streets system, and the buildings system has a lower stability over time than the two first systems.

There is a wide variety of streets, with different shapes and sizes, with different ways of relating with the other streets in the surroundings, and also with different urban functions. The analysis of each of the main elements of urban form that we are developing in this chapter does not ignore that, for instance, the character of a street is influenced by other elements of urban form shaping it. This character is actually influenced by the plots on one or on both sides of the street; by the buildings—by their height and by the relation between their height and the width of the street;

by the way buildings are located in plots, sometimes near to the plot frontage, offering the street a higher sense of enclosure, sometimes far from the plot frontage, offering greater openness to the street; or by the ‘doors’ that these buildings open to the street. Another important issue when analysing the streets system that will be developed in later chapters is how in each street the space for pedestrians and the space for vehicles—public or private, motorized or non-motorized—are distributed. Allan Jacobs’ ‘Great streets’ is an example of a notable book on the streets of our cities (Jacobs 1993). Figure 2.6 presents a diverse set of streets in four different cities.

The first images refer to the intersection of two of the most important streets of New York: the Broadway, which crosses the whole island of Manhattan in the north–south direction, being the only street with an irregular pattern on the orthogonal grid of the city designed in the early nineteenth century; and the 5th Avenue (with 10 kmlong and 30 m wide) which is perhaps the most famous of the eleven avenues that structure New York in the north–south direction. The two following images refer to the Avenue des Champs Elysées in Paris, one of the most important symbols of the Baron Haussmann’ s intervention in the French capital in the second half of the nineteenth century (see Chap. 3).

This is an axe of 2 km long and 70 m wide (in its western part which is clearly more urban), conformed by a fairly homogeneous set of buildings. The buildings height is clearly inferior to the street width, which gives the Champs Elysées a strong sense of openness. It has a strong presence of trees and with very different functions including shops, cafes and cinemas. This avenue is part of a longer axe with a fundamental importance in the city, linking La Defense and the Louvre Museum. The third set of images refers to a small medieval street in Siena, the Via Rinaldini. This street is directly linked with the famous square of the city (that will be analysed in the following paragraphs). Via Rinaldini is less than 50 m length and is 5 m width. Despite the clear differences in relation to the two previous streets, we should highlight that the cross-section of this street is somehow close to the cross-section of the 5th Avenue where the buildings height is clearly higher than the street width. Finally, the fourth set of images refers to the Reguliersgracht, one of the streets of Amsterdam,

within the so-called ‘ring of canals’, an area that started to be built in the early seventeenth century. The built environment of Amsterdam—as well as of other Dutch cities—is marked by a sound presence of water. As such, the cross-section of the street (the street is about 30 m wide and 600 m long) is clearly different from the previous examples, as it includes the canal and, on each side of it, a street with three different spaces: one for pedestrians, one for vehicular traffic (distinguishing it form the urban environment in Venice where there is no vehicular traffic in the historical city) and one for car parking. The public spaces system of a city includes not only the open spaces for movement, which we designate, in a simplified way, as streets, but also the open spaces for permanence, which we designate as squares and gardens. All this diversity of streets that we have described in the previous paragraphs can also be found in the case of squares.

Figure 2.7 presents four squares in three different continents. The first of these is Times Square, in New York, located at the intersection of Broadway with the 7th Avenue. While in morphological terms the square is no more than the intersection of the two streets with no particular conditions inviting for staying in the square (somehow similar to what happens in Picadilly Circus, in London), the truth is that at any time of day or night, Times Square is full of people (as we can see in this photograph taken at night). In terms of urban functions, the square is located in the heart of the Theater District and it includes a number of cultural and commercial activities contributing not only to the dynamics of this space, but also to the consolidation of the image of the square through a significant number of attractive neon lights. Our collective imaginary of this New York square is undoubtedly informed by the traditional party in the New Year’s Eve, when a crystal ball falls from the top of the number 1 of Times Square.

The second square included in Fig. 2.7 is the Place Georges Pompidou, in Paris, near the former market of Les Halles. This square is clearly different from the previous, both in morphological terms and in functional terms. Indeed, the Place Georges Pompidou has a clearly defined shape, a rectangle of about 175 m long and 70 m wide, and a slope upwards from the entrance in the Centre Georges Pompidou, that establishes its eastern limit, up to the buildings of the Rue SaintMartin that constitute its western boundary. This immense sloping surface is one of the fundamental characteristics of the square and is the key element that invites people to different activities, from the simple lay down to different artistic performances. In terms of function, this square is clearly distinguishable from the first because it has a strong artistic dimension, due to the presence of the remarkable Centre Georges Pompidou, built in the late 1970s.
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As a complement, the Place Igor Stravinsky (at south of George Pompidou, in Fig. 2.7) including a set of modern sculptures and the Stravinsky Fountain with 16 mobile sculptures, should also be referred. One of the most famous squares in the world, particularly among those studying the physical form of cities, is the Piazza del Campo in Siena. This Italian square, from the twelfth century, has the shape of a shell and it is delimitated by a number of notable buildings (palazzi) with different heights, from five to seven storeys. Similarly to the Place Georges Pompidou, this square is constituted by a wide sloping surface—following the topography of the city—which has the lowest point in the northern part, in the entrance to the town hall, the Palazzo Pubblico.

One of the most famous events that takes place in the square is the Palio, a horse race which dates back to Roman military exercises. The last example included in Fig. 2.7 is the Meidan Emam in Isfahan, Iran. This square of great dimensions, 520 m long and 160 m wide, has a rectangular shape (as the Place Georges Pompidou) and it is delimitated by a continuous building volume of two storeys high with a double colonnade. A number of exceptional buildings stand out in this set—two notable mosques, classified by the United Nations Educational, Scientific and Cultural Organization (UNESCO), and a palace. The northern part of the square gives access to the Bazaar of Isfahan.

In addition to accommodating some exceptional functions, the square is intensively lived by the local people for many different activities. Contrarily to the three previous cases there is not a strong presence of foreign tourists in Isfahan. As we can find substantially different urban tissues or streets in the same city (as we have seen in the example of New York), we can also find different squares with clearly distinct forms and functions in different parts of the same city. The following paragraphs, and Fig. 2.8, illustrate this phenomenon in Paris. The first example included in Fig. 2.8 is the Place Vendome, located in the Tuileries area. This square was built in the early eighteenth century (it is the latest example of this set). It has a rectangular shape (octagonal cut in the corners) with 140 m long and 120 m wide, it is crossed by one street only—the Rue de la Paix, and it is composed of a group of buildings with a great homogeneity in terms of architectural language and of the number of storeys. In terms of urban functions, Place Vendome is the home of a number of fashionable shops.