Pedro S Gomes
email: pedro.gomes@univ-paris-est.fr

FACTORS OF GOOD PUBLIC SPACE USE

Keywords: public space, public space use, urban design, urban management. Palabras clave: espacio público, usos del espacio público, diseño urbano, gestión urbana public space, public space use, urban design, urban management espacio público, diseño urbano, gestión urbana

This paper presents a literature review of some of the most relevant work in the field of urban planning on the relationship between the characteristics of public spaces and their use. The synthesis put forward focuses on the characteristics of public spaces which contribute to their intense use. The former relate to urban form and public space design and management.

INTRODUCTION: ON THE RELATIONSHIP BETWEEN URBAN PUBLIC SPACES AND USE

This paper presents a synthesis of some of the urban planning literature on the relationship between the characteristics of public spaces and their use, which often takes the shape of guidelines or operative recommendations. While deterministic views on the relationship between spaces and their use have long seen their heyday, the former are still seen as powerful influences on individual and collective behavior.

The issue of public space use is one of space and use, with individual behavior and spatial practices at its core. Understanding its dynamics and investigating the potential role of urbanism in its promotion requires that the spatial, social and experiential conditions of the phenomenon (SIMÕES AELBRECHT, 2010) are taken into account. It also means coming to terms with the fact that planning, design and management's impacts on public space use will always be limited.

The concept of affordances further emphasizes the limited influence of spaces in their use. In Gibson's simplest formulation, 'the affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill ' (1979' ( , quoted in CHEMERO, 2003: 182): 182). They are, then, properties of the environment, but relationally defined with reference to an individual, 'they implicate a particular receiver' (HEFT, 1989, p. 4). Or, in other words, an affordance is 'the functional utility of an object for an animal with certain action capabilities. […] It is the combination of environmental properties that supports some activity for a particular animal' (WARREN, 1984: 683). Therefore, affordances exist whether or not they are being perceived (McGRENERE & HO, 2000) and one object may have multiple affordances (HEFT, 1989), as it may be used in several ways, for several purposes, by different agents.

The concept does not, consequently, propose explanations for action (and use): there are potential and actualized affordances, whose counterparts are potential and actualized intentional acts (HEFT, 1989). Further conditions are needed, related to the agent, namely perception and motivation (GREENO, 1994). The importance of perception as a precondition for action stresses the importance of sensorial experience in questions of public space use; aesthetics will then always be one of the possible areas of intervention. So, firstly, in order for a given object to be used, it needs to be perceivable. Furthermore, it needs to be perceived as usable, which raises issues of ergonomics. Additional work on affordances (WARREN, 1984;WARREN & WHANG, 1987) has shown that perception is body-scaled, meaning that objects will be perceived as affording a given action in relation to the individual's body metrics, there being somewhat stable critical and optimal points establishing functional perceptual categories and preferences. While the notions of critical and optimal points refer strictly to matters of ergonomics, they allow for an analogy on the importance of comfort in the use of objects. Being perceived as usable also raises matters of signification -(social) signifiers (NORMAN, 2008) which provide clues to the operation of objects and how they can be used (McGRENERE & HO, 2000). Thus, there is also a semiotic and symbolic dimension to the promotion of action.

Still, ability and consciousness of that ability are not enough to explain action. Perception of affordances is further influenced by culture, in that much of the functional meaning in perceptual experience is culturally-derived, through different learning processes; affordances should be understood in relation to what an individual knows how to do, and this situated knowledge is often acquired within specific sociocultural contexts (HEFT, 1989). The perception of affordances thus varies with individual factors, through time and space, it is situational. This opens the way to including norms as constraints of action in public spaces, both social norms determining acceptable behavior and institutionalized ones which regulate use. The normative stance of individual action, too, varies through different situations (THÉVENOT, 2001). In other words, besides being able to do something and recognizing one is able to do so, it is also a question of thinking one should or might do it. The production of public space may then directly or indirectly seek to influence the social norms governing the perception of admissible and 'good' uses of spaces.

Intentions or motivation also influence perception: 'motivation to engage in some action is related to what the agent is doing in a more general level […] [making] the person more attentive to aspects of the environment that could provide an affordance [for the action]' (GREENO, 1994: 340). The promotion of public space use may then consider people's intentions and motivation; location of 'functions' can accordingly be used as promoters of use and the production of public spaces may explicitly attempt to address individual and collective needs.

Aesthetics, ergonomics, symbols, social norms, regulation of uses, location of activities and users' public space needsall these issues are relevant are important for the promotion of public space use, as the analogies with affordance theory allowed to show2 . However, they do not address one fundamental dimension of public space use: the political one. The genesis of the concept of public space as an analytical and action category is closely linked to political philosophy [START_REF] Fleury | Réflexions au croisement de trois expériences: de Paris aux quartiers centraux[END_REF] and the fact that public spaces are spaces of collective use and often of State property pose the question of their relationship with the common interest and democracy. Therefore, to the aforementioned issues, there is an additional one to take into account, that of rights.

DEFINING PUBLIC SPACE AND GOOD PUBLIC SPACE USE

'Public space is […] an 'essentially contested concept'. It is internally complex, enables a variety of interpretations in different domains, and has both normative as well descriptive connotations' (KOHN, 2008: 480). For the purposes of this paper, the definition of public space focuses on its descriptive connotations; its normative stance is approached through the exploration of what good public space use might be. Public space is thus defined as the ensemble of state-owned, free access open spaces (cf. GOMES, 2011: 7-17 for the discussion leading to the definition).

Put simply, good public space use is marked by conviviality, overall pleasantness accessibility and openness and it allows for essentially distinct situations, some of them marked by multiplicity and 'situated surplus' [START_REF] Amin | Cultura col-lectiva i espai public urbà / Collective culture and urban public space[END_REF], others by the presence of homogenous groups of users and strong place appropriation.

FACTORS FOR GOOD PUBLIC SPACE USE

This section aims to identify the characteristics of public spaces which promote good public space use. This is not to suggest any sort of mechanistic causal relationship. In a relational view of phenomena, 'there is a continuous "stream of behavior" or a stream of transactions between environment and individual. Breaking into this stream of transactions at any particular point to find an environmental cause for some specific behavior is not only typically arbitrary but also potentially misleading. It is arbitrary in the sense of determining when in time to look for an antecedent cause of a behavior, and it may be misleading in that it suggests that "cause and effect" can be limited to a specific environmental event and a specific behavioral act' (HEFT, 1989: 8, original emphasis). Moreover, 'causal influences are reciprocal, with the impetus of fluctuations in the on-going behavior stream having its source in the environment facet or in the individual facet of the transaction; and this reciprocal exchange is cumulative in its effects' (HEFT, 1989: 9, original emphasis). Some of these factors contribute to a space's success; others are necessary. But none of them is sufficient (JACOBS, 1995).

Possibility

Perhaps the first precondition for good public space use is the mere presence of people in public spaces. This raises the question of how possible that presence actually is; in other words, it poses the question of accessibility and access. And it does so at different scales: on a broader one, it is a matter of how pedestrian friendly the overall environment is; on a bigger one, it deals with accessibility to actual spaces, in its threefold understanding: physical, visual and symbolic (CARR [START_REF] Carr | Public space[END_REF].

The impacts of motorized mobility in the walkability of urban areas are pervasive and have been summarized in the metaphor of an 'invaded space' (CARMONA ET AL., 2008: 45), emphasizing the splintering of urban areas, the diminution of public spaces' social function due to motorized transport's ubiquity and the substitution of traditional public space and landscapes by car-dependant areas.

Many public space design recommendations acknowledge the importance of countering these tendencies as an overarching challenge for urban public life, regardless of interventions in particular spaces; hence the myriad pleas for urban density, compactness and mixed-use developments and the restriction of car use. Thus residential density, by a simple question of numbers of ease of access, increases street use, particularly beyond working hours (JACOBS, 1995). Furthermore, residential density influences the type of sociability in public spaces. Mixed-use areas will provide multiple attractors (see following section), for different people, including their workers (MARCUS & FRANCIS, 1990), with different purposes at different times, thereby contributing to a constant use of spaces (JACOBS, 1995;STEVENS, 2007).

Density and diversity of the surroundings are a question of possibility due to public spaces' limited area of influence in attracting users, in terms of distance and time (MARCUS & FRANCIS, 1990;MOURA E SÁ, 2010;WHYTE, 1990). The urban fabric's compactness is consequently an additional requirement, in order to maintain short distances and sensory experiences (GEHL, 2006). Reversing the reasoning, it is the location of public spaces in relation to the constituency it aims to cater to which becomes a crucial factor for its use.

But possibility has also to do with physical, visual and symbolic accessibility to specific spaces. Physical limitations may stem from restrictive opening hours, from the presence of guards, fences or gates which might discourage people from entering the spaces; entrances should be well connected to paths and smoothly transition to the surrounding sidewalk. There are other barriers to access which primarily affect certain user groups, such as stairways or car predominance in residential areas. Visual and symbolic access to spaces is also important, in that the possibility of access should also be easily perceived, and symbolic cues, via design elements or people, communicate which users and uses are acceptable. Public art can also play a role in the correction of 'symbolic injustice' (FRASER, quoted in SHARP ET AL., 2005) communicating diverse and multiple images of the urban collectivity, besides a more prosaic role in improving space image (WHYTE, 1990). Symbolic access is also a question of convenient signage and entrance design.

Possibility is a formal matter as well, in that public space elements' size and shape determine the activities which may take place within. As these refer to an adequacy between specific design features and discrete activities in public spaces, they will be discussed in the following section, which proposes users' motivation as an entry for addressing the production of public space.

Motivation

In the previous section, it was mentioned how diversity of uses may function as attractors for diverse users. In the brief discussion of affordances, motivation was put forward as a condition of perception and use of a given affordance. This section will elaborate on these ideas by suggesting that users' motivation for using public spaces may be a fruitful entry for thinking their production. Echoing the concept of affordances yet again, it is a matter of thinking public spaces and their constituent elements as supply for different users with equally differing motivations.

It is a matter of having 'things to see and do' (GOMES, 2011), which intersects GEHL's (2006) notion of necessary, optional and social activities in public spaces. Necessary activities are relatively compulsory for its participants, including shopping, going to work… Optional ones are, conversely, those one undertakes willingly or if the time and place allow. Social activities, often the consequence of necessary and optional ones, require the presence of other individuals.

The production of public space may then initially adopt a rather functional approach, focusing on two main public space functions: circulation and access to surrounding buildings, which are deeply connected. The spatiotemporal distribution of necessary activities is thus a mechanism for supporting optional activities, preventing single-function areas and class-specific buildings which may monopolize the social life of public spaces (STEVENS, 2007). Density, diversity and concentration of activities will all play a role. On a micro-scale, this integration of activities, functions and their users in and around public spaces may spark collective actions that mutually stimulate and inspire each other, which is why GEHL (2006) suggests that more than the formal integration of building and functions, it is the real integration of several happenings and people on a larger scale that should stem from contact surfaces.

This approach through motivation can also focus on some of people's public spaces needs, namely relaxation, passive and active engagement (CARR ET AL., 1992). The need for relaxation counterbalances the previous apology of concentration of activities and flow generators, by stating the need for different densities of activities and intensities of public life. Passive engagement broadly refers to an encounter with the environment, other people included, but without being actively involved (active engagement). While relaxation addresses a certain need of retreat from the liveliness of cities, the remaining needs seek it.

The different effects of residential density on the modalities of public life have already been pointed out, as well as the role of visual and symbolic access in suggesting different ambiances. The latter should also be highlighted by an urban fabric clearly differentiating hierarchically distinct spaces (GEHL, 2006). Visual access allows an assessment of whether the space is appropriate to the individual's wants and needs at that particular moment, but ought to be balanced with the need for privacy in public spaces. Clear yet subtle subdivision of public spaces, especially in larger ones, is one way of promoting different atmospheres in one space [START_REF] Brandão Alves | Avaliação da Qualidade do Espaço Público Urbano[END_REF][START_REF] Carr | Public space[END_REF]. Because relaxation is a search for a break from city life, it is intimately connected with the role of 'nature' in urban settings due to its sensory qualities. These elements ought to be combined with sittable ones in order to reinforce their 'urban oasis' character (MARCUS & FRANCIS, 1990). Finally, relaxation also requires a sense of safety.

The promotion of passive engagement is a question of providing 'things to see', including people, and conditions for seeing. Other people is one of the most effective attractors of public space users (WHYTE, 1990), because people watching is a favorite activity. Every element which attracts users to public spaces has, therefore, the potential to promote passive engagement.

Moreover, the environment may be an attractor for contemplation by itself. The creation of 'spatial sequences' (GEHL, 2006) can make the environment more appealing, thus promoting use. Spaces and buildings can be attractors, too, be it for their aesthetics, historical significance or symbolism. In some cases, these may generate considerable flows of people. However, the aesthetic appeal of spaces is often more mundane, as the visual complexity of spaces, namely the density and variety of elements, offers possibilities for passive engagement (MARCUS & FRANCIS, 1990).

Passive engagement also requires conditions for seeing, and these correspond to two main issues: vantage points/sightlines and seating areas. Whenever there are activity foci or focal points in the space's form, people tend to seek appropriate points from where to watch the scene. These are usually the spaces' edges (DE JONGE, quoted in GEHL, 2006), elevated areas or even surrounding buildings. While height differences provide opportunities for passive engagement with public spaces, they hamper direct forms of interaction. The fruition of these views requires elements where one can conveniently sit on or lean against. Sittable elements, more than formalized seats, are one of the most relevant elements in the promotion of long stays in public spaces, especially for those entailing optional and social activities (GEHL, 2006;WHYTE, 1990). They should be conveniently oriented and located, as most people who sit down in public spaces do so to enjoy one of the advantages the space provides, the site, the space, the weather, ongoing activity, or everything all at once. A variety in orientations creates a variety of exposure to weather and of sightlines, which are two of the most relevant criteria when choosing where to sit in a public space (GEHL, 2006).

Active engagement presupposes all of the conditions for passive engagement and most elements in public space afford some sort of interaction. They can, however, clearly promote it. Or, conversely, certain uses may be actively discouraged or even impeded. So, before addressing design features, it should be stressed the role that use regulation practices play in dis-and encouraging active engagement.

One important notion in active engagement with the environment, particularly in what concerns the promotion of sociability, is that of triangulation (WHYTE, 1990), the ability of a given public space element to motivate conversation or other sort of interaction between two or more individuals who are not necessarily acquainted. The precise conditions for socializing will vary, but noise is always an important factor in conversation. Seating may be arranged in ways which promote or at least allow socialization -'conversational landscapes' (GEHL, 2006). Water and public art are often introduced in public spaces to promote relaxation and passive engagement, but their benefits will be increased if access to them is actually given (WHYTE, 1990) and interaction actively promoted. Active engagement also benefits from the activities proposed in public spaces themselves. Three types seem to be particularly relevant: food and beverages, commerce and street art, entertainment and events. The latter can be encouraged by spaces' physical elements, including design features and management strategies and infrastructural provision which anticipate the specific requirements of such activities (MARCUS & FRANCIS, 1990;WHYTE, 1990).

Opportunity

Scholarly work emphasizes how much of (good) public space use depends on chance encounters, unplanned activities and an openness, both of public spaces and of their users. This section presents a few remarks on how the production of public space may seek to enhance the opportunities for such activities beyond strict possibility and answering to individual motivations.

The connectivity and permeability of urban fabrics allow for a multiplicity of alternative paths and interconnections between different spaces. A given public space may then serve as the final destination for some users, a place to pass through and a secondary or an incidental destination for others (ALEXANDER, 1965, quoted in STEVENS, 2007). Together with the compactness of the tissue, these spaces, comprising different, interconnected and overlapping circulation routes, increase individual choice and hamper strict control, contribute to a higher probability of chance, the unexpected and of contact with a larger diversity of people and actions (FRANCK & STEVENS, 2006). Spaces' location in relation to the block or open space network, particularly of small squares, provides opportunities for different kinds of use (MARCUS & FRANCIS, 1990). Questions of visibility and symbolic access also play a role in the perception of these opportunities. The amount of sittable areas influences the opportunities for unplanned activities, by inciting longer stays and engagement with the scene.

Besides the role of buildings and their functions in attracting visitors, a smooth transition between private and public realms can promote opportunities for public space use. The relationship is bidirectional. Transparency (JACOBS, 1995) allows for public space users to easily perceive what lies beyond building façades, providing possible points of interest and comfort by communicating that the space is inhabited and that there are possibilities of retreat (GEHL, 2006;JACOBS, 1995). Furthermore, the density of public-private interaction areas provides opportunities for use as well (GEHL, 2006), through multiple entrances, buildings and narrow façades. Particular care should be taken in defining the activities on buildings first two floors, privileging the ones with the most beneficial effects on public space use (WHYTE, 1990).

Comfort

Physical and psychological comfort is a very strong condition for optional and social activities in public space, including long stays.

One fundamental dimension of physical comfort relates to the weather, in that public spaces should afford protection from unpleasant conditions and fruition of pleasant situations. Public spaces should be designed so that as much of their area falls under people's 'comfort zones', the ensemble of physically comfortable weather conditions for a person to be casually dressed under the shade as a desirable public space scenario (MARCUS & FRANCIS, 1990).

Exposure to sunlight should then be maximized (MARCUS & FRANCIS, 1990), but shelter should be provided for too warm situations. When direct exposure is not possible, reflecting surfaces and unobstructed skylines should be explored, so long as glare is cautioned for (MARCUS & FRANCIS, 1990;WHYTE, 1990). Accordingly, the material of sittable surfaces should not be overly responsive to temperature. As temperature is often more crucial than sunlight (WHYTE, 1990), shelter from wind should be catered for. Besides avoiding high-rise buildings, the design can provide secluded nooks. More generally, short buildings and sinuous street networks have a positive effect in wind protection (GEHL, 2006).

Noise is another environmental feature with significant impacts on the overall comfort of spaces, especially for conversation and relaxation. White noise, such as water, may filter it down (WHYTE, 1990). Space maintenance is also an important factor for comfort. Material choice ought to anticipate future maintenance in relation to available resources (JACOBS, 1995).

Physical comfort also implies questions of ergonomics. While level changes can have positive effects, they are always an obstacle to be generally avoided. If not possible, design should hint and promote an ease of use through gradual and short slopes and ramps (GEHL, 2006), in spite of steps' sitting affordance (WHYTE, 1990).

Sidewalk width is a relevant issue in securing comfort in public spaces, but there are no optimal sidewalk widths, as they depend on motorized traffic flows, density and type of surrounding functions, frequency of access to buildings and parcels, on the need for greenery, street furniture and parking spaces (MOURA e SÁ, 2010). But absolute metrics also matter, as they allow for different degrees of liberty in circulation. Sittable elements' height should be defined according to a person's average height, even though certain groups of users may choose less comfortable seats according to their needs. Deep, backless benches allow for people to sit on both sides, but at least some seats with backs should be provided for less physically fit users (GEHL, 2006;WHYTE, 1990). Although they have become rarer in public spaces, due to vandalism, insecurity and high maintenance requirements (WHYTE, 1990), public toilets are relevant for increased comfort and longer stays in public spaces [START_REF] Carr | Public space[END_REF].

One aspect of psychological comfort relates to the spatial definition of the environment, as it may increase comfort and the overall pleasantness of the experience, especially regarding the parameters of visual perception. Spaces are defined vertically by building, wall and tree heights and horizontally by the extension and spacing of the defining elements (JACOBS, 1995). Vertical definition is as much a question of proportion as of absolute size: the wider a street is, the bigger building height or mass will have to be in order to appropriately define the space. In spite of several metric guidelines, spaces' absolute size does not seem to be a critical factor for use (WHYTE, 1990). Spacing between buildings is crucial in streets' horizontal definition; as for their vertical definition, it is unclear which absolute dimensions or ratios determine it. Jacobs (1995) states that smaller spacing between buildings provides better definition when compared to bigger ones. Street length is also relevant for definition, even though it is not crucial. Still, too long a street will struggle to keep visual interest and diversity (JACOBS, 1995). Changes or variations in street profile and focal points might mitigate such effects of excessive street length. (JACOBS, 1995). In too wide streets, regularly spaced trees and other vertical elements can be used to scale them down, sometimes by subdividing them (JACOBS, 1995). Comfort and pleasantness are also promoted when buildings are complementary, thus transmitting a sense of regularity and order, implying similarity in both look and height (JACOBS, 1995), but not necessarily synchronous development nor stylistic resemblance.

Motorized traffic is the second aspect with a deep impact on public space use, also at a micro-scale. Intense or fast traffic in the spaces' surroundings especially impacts non necessary activities, as it decreases comfort and restricts pedestrian movement (Gehl, 2006). These negative impacts of motorized traffic are connected to perceived and actual levels of safety. Too scarce a pedestrian area for existing flows will be uncomfortable and dangerous by leading pedestrians to use the carriageway (Whyte, 1990). While the physical separation of pedestrian and motorized flows has been the most common measure to secure pedestrians, it does not necessarily provide them with a sense of safety and tranquility. These can be intensified by trees and longitudinal parking (A. B. Jacobs, 1995). In narrow and very busy streets, and in residential ones, shared spaces may be the safest option (Gehl, 2006;A. B. Jacobs, 1995).

Furthermore, safety concerns regarding criminality are one of the strongest drivers of present public space policy and are a fundamental part of psychological comfort in public spaces. The legitimate concern for promoting people's safety has led to efforts in controlling public space use, through management and design measures. Management has growingly focused on security, namely by increasing surveillance, through policing or CCTV, whose dissuasive effect is debatable [START_REF] Carmona | Public space: the management dimension[END_REF]. More important is the tense relationship between the promotion of security and broader issues of accessibility to public spaces, as administrations have actively sought to eliminate certain behaviors and user categories from public spaces.

'Eyes on the street' is another strategy for promoting public space safety with a rather different rationale. Following Jane Jacobs (2010), it emphasizes how public space users and those of surrounding buildings can play a fundamental role in deterring crime and vandalism. Indeed, it is because there are usually less people outside and there is less visibility that the perception of danger is more acute at night. Good lighting should be warm, welcoming, abundant and oriented towards socially relevant aspects, people and their faces, and horizontal surfaces, and not too intense, as it may cause glare (Gehl, 2006;A. B. Jacobs, 1995).

CONCLUDING REMARKS

This body of research has put forward a solid understanding of the factors of good public space use, and how they relate mostly to urban design and public space design and management. Overall, it stresses the relevance of pedestrian friendly environments and their recommendations coincide with the canons of traditional, compact and continuous, and diverse and fine-grained urban fabrics. The issue they fail to address, however, is that much of contemporary metropolitan territories are the quasi-negative of the situations they describe and/or propose: splintered, fragmented, monofunctional areas dominated by motorized transport. The answer to how to promote public life in such territories remains to be given. By focusing on spaces as units of analysis and less on how their use makes part of people's everyday lives, it becomes harder to imagine spatial configurations beyond the 'classical city' which can foster good public space use.

Furthermore, while there are guidelines on how to promote spaces with different ambiances and dynamics of use, little is said on what rationale could or should be adopted in deciding what is to be promoted in a given space (program definition). This becomes clearer when, even though all work acknowledges the importance of the overall urban fabric and public space network, little is said on how public space planning can undertake a holistic/systemic/network approach at an urban scale.

N.B.: Affordance theory is a perception theory, not a pragmatic one.

1 This article is part of an ongoing PhD research supervised by Alain Bourdin and Jorge Carvalho and financed by Portuguese and ESF funds by FCT (grant reference SFRH/BD/78852/2011)

de Berlin et Istanbul (PhD Thesis), Paris, Université de Paris 1 Panthéon-Sorbonne, Paris, 685 p. FRANCK, K. A., & STEVENS, Q. (2006): «Tying Down Loose Space», in FRANCK K. A. & STEVENS, Q. (ed.), Loose Space: possibility and diversity in urban life, London, Routledge, p. 1-33 GEHL, J. (2006): La humanización del espacio urbano: la vida social entre los edificios, Barcelona, Editorial Reverté, 227 p. GOMES, P. S. (2011): Vivacidade. A animação do espaço público como estado e como acção municipal (Master's dissertation), Lisbon, Universidade Técnica de Lisboa, 197 p. GREENO, J. G. (1994): «Gibson's Affordances», Psychological Review, v. 101 n. 2, p. 336-342 HEFT, H. (1989): «Affordances and the Body: An Intentional Analysis of Gibson's Ecological Approach to Visual Perception». Journal for the Theory of Social Behaviour, v. 19, n. 1, p. 1-30. JACOBS, A. B. (1995): Great streets. Cambridge, MA: The MIT Press. JACOBS, J. (2010): «The Death and Life of Great American Cities», in ORUM, A. P. & NEAL, Z. P. (ed.), Common Ground? Readings and Reflections on Public Space. Londres: Routledge, p.18-31 KOHN, M. (2008): «Homo spectator», Philosophy & Social Criticism, v. 34, n. 5, p. 467-486. MARCUS, C. C., & FRANCIS, C. (1990): People Places. Design Guidelines for Urban Open Space, New York, Van Nostrand Reinhold, 369 p. McGRENERE, J., & HO, W. (2000): «Affordances: Clarifying and Evolving a Concept», Proceedings of the Graphics Interface 2000, Toronto, Canadian Human-Computer Communications Society, p. 179-186 MOURA E SÁ, F. (2010): Espaço Público à Escala Local (Master's dissertation), Aveiro, Universidade de Aveiro, 191 p. NORMAN, D. (2008): «Signifiers, Not Affordances», Interactions, v. 15, n. 6, p. 18-19. SHARP, J. ET AL. (2005): «Just Art for a Just City: Public Art and Social Inclusion in Urban Regeneration», Urban Studies, v. 42, n. 5-6, p. 1001 -1023. SIMÕES AELBRECHT, P. (2010): «Rethinking urban design for a changing public life», Journal of Place Management and Development, v. 3, n. 2, p. 113-129. STEVENS, Q. (2007): The Ludic City: exploring the potential of public spaces, London, Routledge, 248 p. THÉVENOT, L. (2001): «Pragmatic regimes governing the engagement with the world», in SCHATZKI, T. R. ET AL. (ed.), The Practice Turn in Contemporary Theory, London, Routledge, p. 56-73 WARREN, Jr., W. H. (1984): «Perceiving Affordances. Visual Guidance of Stair Climbing», Journal of Experimental Psychology: Human Perception and Performance, v. 10, n. 5, p. 683-703 WARREN, Jr., W. H., & WHANG, S. (1987): «Visual Guidance of Walking Through Apertures: Body-Scaled Information for Affordances». Journal of Experimental Psychology: Human Perception and Performance, v. 13, n. 3, p. 371-383 WHYTE, W. H. (1990): City: Rediscovering the Center, New York, Anchor Books, 386 p.


Pedro S Gomes
email: pedro.gomes@univ-paris-est.fr

Taking 'use' into account in the production of public space in Lyon, Louvain-la-Neuve and Lisbon Contexts, methods and results

Keywords: production of public space, public space use, Lyon, Louvain-la-Neuve, Lisbon

Issues of public space use have become a paramount subject of research in the recent past. While research of an overtly operative outlook has convincingly put forward design and management recommendations for improving the use of public spaces, it has struggled in approaching the issue as the scope of urban policy and planning. This research project aims at contributing to re-placing the problem at an urban scope. It will do so by comparing three very different policy and planning processes which, at an urban scale, explicitly put forward use as a main objective of public space production, namely Lyon, Louvain-la-Neuve and Lisbon.

This research adopts an inductive approach to the subject, framed by readings in the intersection of pragmatic sociology, policy and economics/management studies which suggest the explanation of policy outcomes by in-depth analyses of the processes leading to them. However, it maintains a geographical standpoint as it is concerned, as well, with the "spatialization of public policies", i.e. the spaces that are actually produced by said processes and the dynamics of use taking place therein.

I. PROBLEM AND RELEVANCE OF THEME

The problem of this thesis is how to produce public spaces which foster 'good' uses, i.e. which are marked by conviviality, overall pleasantness, accessibility, some of them imprinted by multiplicity and 'situated surplus' [START_REF] Amin | Cultura col-lectiva i espai public urbà / Collective culture and urban public space[END_REF], others by the presence of more homogenous groups of users and communitarian appropriation dynamics [START_REF] Gomes | A animação do espaço público como estado e como acção municipal[END_REF]. Such concerns have been around for long, especially since criticism of functionalist, technocratic approaches to urban planning began to arise. In fact, the genesis of 'public space' as an operative and analytical category is linked to critiques of modernism and to the rise of a post-industrial city [START_REF] Fleury | Les espaces publics dans les politiques métropolitaines. Réflexions au croisement de trois expériences: de Paris aux quartiers centraux de Berlin et Istanbul[END_REF].

The subject of such concerns has, however, expanded. Early urban commentators usually criticized the impact of functionalist urban forms, zoning techniques, traffic segregation and the privilege of individual motorized transportation on social life. Nowadays, even though earlier concerns persist, the social and political effects of neoliberalism and globalization in urban policies and of the rise of a 'metropolitan civilization' [START_REF] Bourdin | La métropole des individus[END_REF] have also come to the fore. Public spaces and their use are thus often seen as epiphenomena of broader, structural changes in society. Why is it, then, that producing public spaces (programs, designs, and management) which foster 'good' dynamics of use is a relevant research theme and policy goal? Even though the exact role and the importance of public spaces as an arena of social and civic formation are debatable, there seems to be an agreement on the significance of conviviality in public spaces for a broader notion of urban culture and civitas [START_REF] Amin | Cultura col-lectiva i espai public urbà / Collective culture and urban public space[END_REF]. Actions on public spaces may, then, contribute to minimize the negative consequences of structural trends, namely by influencing users' individual and collective behavior.

II. OBJECTIVES AND RELATED RESEARCH TOPICS

The main objective of this research is to contribute to a methodological framework for public space production centered on its use, at an urban scale. Such a framework may entail two different domains of enquiry, one substantive, the other procedural. From a substantive point of view, related research topics regard the relationship between public spaces and use dynamics therein. It becomes, for the most part, a question of urban design and management, by seeking an understanding of how given characteristics of public spaces and of their administration can promote or deter certain uses. Or, conversely, of understanding how can different characteristics of public spaces answer to individuals' needs or demands. The procedural dimension of the problem is twofold. On the one hand it addresses the actual reasons, processes and methods which 'taking use into account' might entail, from the adoption of guidelines based on existing research to different sociological surveys in the field and participatory processes, among others. On the other hand, it implies an understanding of the processes of public space (and city) production themselves, in order to identify the potentially most effective ways of formalizing any operative recommendations. This research thus poses four interrelated questions to the case studies. First, how, and why, have public space and public space use become privileged policy goals? Secondly, how have these goals been translated in the specific production processes and how can different options be explained? Thirdly, what have been the results of these policies, in terms of the actual spaces created and the dynamics of use within them? And, finally, what can these case studies teach that might give shape to a methodological framework for producing well used public spaces at an urban scale?

III. BRIEF PRESENTATION OF WHAT IS ALREADY KNOWN

Given the research topic's broadness, it intersects a number of different approaches and fields of scientific enquiry.

A. Microsociology, affordance theory and urban ambiances

Dating back to predecessors in the Chicago School [START_REF] Joseph | El transeunte y el espacio urbano[END_REF], sociologists have put forward detailed accounts of public sociability [START_REF] Joseph | El transeunte y el espacio urbano[END_REF][START_REF] Goffman | Behavior in public places[END_REF]. Displacing the analysis of publicness from spaces or users to situations [START_REF] Joseph | El transeunte y el espacio urbano[END_REF][START_REF] Goffman | Behavior in public places[END_REF][START_REF] Bordreuil | Espace public, urbanité et mouvements[END_REF][START_REF] Boissonade | Une urbanité de confrontation. Regroupements de jeunes et gestionnaires de l'espace urbain[END_REF], they have shown how public sociability is defined by an ensemble of behavioral norms, small gestures and bodily practices [id.] and how local social orders are constructed through everyday practices of conflict and negotiation [START_REF] Nunes | Jouer son atout": figuration et sociabilité de rue dans une banlieue de Lisbonne[END_REF]. These studies main concern has been more on how public life comes about in interactions between people, and less the spatial conditions behind them [START_REF] Aelbrechts | Rethinking urban design for a changing public life[END_REF]. The clues they provide have, however, been appropriated and further developed by research with more operative aims, which has provided useful insights for urban design, as the following section will show. Moreover, by focusing less on the spatial conditions of public life, the political implications of public spaces may be overlooked, e.g. in identifying how sociability in shopping centers portrays every trace of public situations [START_REF] Bordreuil | Urbaniser le mouvement ? Flux et interactions[END_REF].

The need to conceptualize public space use in terms of situations has been further emphasized by affordance theory's take on environmental perception. Visual perception has always influenced architecture and urban design, namely in considerations around scale. Where affordance theory innovates is in presenting a relational understanding of the environment which surpasses narrow subject-object approaches to perception. An affordance, 'the functional utility of an object for an animal with certain action capabilities' [START_REF] Warren | Perceiving affordances: visual guidance of stair climbing[END_REF] is relational in character, as it depends on an individual agent's characteristics. It is a property of the environment [START_REF] Heft | Affordances and the body: an intentional analysis of Gibson's ecological approach to visual perception[END_REF] that exists independently of perception [START_REF] Mcgrenere | Affordances: clarifying and evolving a concept[END_REF]; an object may have multiple affordances [START_REF] Heft | Affordances and the body: an intentional analysis of Gibson's ecological approach to visual perception[END_REF], as it may be used in several ways, for several purposes, by different agents. It is thus a potential characteristic and its use depends on intentional acts in particular streams of behavior [START_REF] Heft | Affordances and the body: an intentional analysis of Gibson's ecological approach to visual perception[END_REF] conditioned by perception and motivation [START_REF] Greeno | Gibson's affordances[END_REF], body-scale [START_REF] Warren | Perceiving affordances: visual guidance of stair climbing[END_REF], social signifiers and use cues [START_REF] Mcgrenere | Affordances: clarifying and evolving a concept[END_REF][START_REF] Norman | Signifiers, not affordances[END_REF], culture and situational contexts [START_REF] Heft | Affordances and the body: an intentional analysis of Gibson's ecological approach to visual perception[END_REF]. Affordances have been little applied to research on public spaces, yet they show how aesthetics, ergonomics, symbols, social norms and use regulations, location of activities and users' needs and motivations play a role in perception and, possibly, action. Still, this research mostly focuses on visual perception, cognition and a rather utilitarian approach to practices. Work on urban ambiances, too, highlights the mediating role of perception between the environment, action and sense making [START_REF] Bourdin | Des ambiances à l'offre urbaine[END_REF]. Drawing on both phenomenological and pragmatic traditions, it stresses how the experience of place takes place in comprehensive, diffuse and indivisible atmospheres, mediated, in context, by all the senses and the body, cognitively and affectively [START_REF] Thibaud | L'horizon des ambiances urbaines[END_REF]. These studies have brought great insight on the role of the sensorial in architectural and urban environments, and shown how design should integrate a subjective and active view of perception; yet, they struggle to investigate how ambiances may be instrumentalized by practitioners [START_REF] Bourdin | Des ambiances à l'offre urbaine[END_REF]. Shopping centers and, following their suit, town centers have been the forerunners of such endeavors [START_REF] Basile | Gérer les espaces intenses: le town centre management britannique et belge[END_REF], but, as much critical work has denounced, such instrumental use might be socio-politically pernicious.

B. Urban design

One prolific line of research addresses the substantive dimension of the problem. For the most part prescriptive, it has given way to an array of recommendations, especially design ones. Among them, several invoke studies of behaviorenvironment interactions for subsequent generalization on the role of spaces [START_REF] Gehl | La humanización del espacio urbano: la vida social entre los edificios[END_REF][START_REF] Marcus | People Places. Design Guidelines for Urban Open Space[END_REF][START_REF] Whyte | City: Rediscovering the Center[END_REF][START_REF] Carr | Public space[END_REF], while others depart from more formal analyses of the built environment [START_REF] Brandão Alves | Avaliação da Qualidade do Espaço Público Urbano[END_REF][START_REF] Jacobs | Great streets[END_REF][START_REF] Montgomery | Making a city: urbanity, vitality and urban design[END_REF]. The guiding notions of "good" uses and spaces behind them are often implicit and empirical data is presented in ways that not always make the connections between certain dynamics of use, spatial/situational quality and spaces' characteristics clear. Remarks on the relationship between prescriptive research and substantive knowledge, wherein several normative theories resort to empirical research to justify or give substance to a priori assumptions [START_REF] Moudon | A Catholic Approach to Organizing what Urban Designers Should Know[END_REF], are thus pertinent. Notwithstanding these possible limitations, urban design literature reached an apparent consensus on how urban administrations may promote an intense use of public spaces. Generally, recommendations coincide with the canons of the compact city, namely with those of classical forms. They highlight how questions of scale, density, diversity and permeability, as well as the offer of things to see and do in both physically and psychosocially comfortable contexts, are relevant for public space conviviality [START_REF] Gomes | A animação do espaço público como estado e como acção municipal[END_REF]. They also show how public space use has a self-regulatory capacity that might downplay the need for more severe regulatory management practices, often criticized as exclusionary.

Research in transportation and public health on the relationship between the built environment and travel behavior or physical activity has generally agreed on the importance of density, mixed land uses, street network connectivity, design details, safety and aesthetics for the promotion of walking and bicycling [START_REF] Saelens | Built environment correlates of walking: a review[END_REF], thus globally concurring in apologies of compact urban forms. It does not provide detailed public space design guidelines, as it still struggles in establishing causality between specific environmental features and walking/cycling. Understandably, it does not approach questions of street use. A recent exception has compared the effects different traffic reduction schemes on street use [START_REF] Biddulph | Street design and street use: comparing traffic calmed and home zone streets[END_REF], but more evidence is needed before generalization.

To sum up, while this research clearly challenges the substance of urban design, it does not necessarily question existing procedures (management being the exception)they can often be read as poignant claims for a severe rewriting of the 'function' in 'form follows function' without scraping off the dictum [START_REF] Stevens | The Ludic City: exploring the potential of public spaces[END_REF]. In spite of these achievements, there is an apparent "dead end" in its operative potential, as it struggles in dealing with the metropolitan scale, and particularly with public life in peripheral and/or splintered urban contexts. Service polarities or large public spaces devoted to leisure seem to be the only existing propositions for these areas [START_REF] Bourdin | La métropole des individus[END_REF], as well as the development of compact suburban enclaves. Moreover, most of these studies conceptualize and analyze public spaces individually; each space is a single entity and both questions and solutions are sought within its boundaries. Their integration in a system, or network, of public spaces is approached in a rather non-systematized manner, besides acknowledgement of the importance of urban fabrics, density and diversity for intense public space use. In other words, spaces have been the privileged units of analysis. Moving beyond this 'punctual' understanding of public space use requires that space and use become units of analysis, namely research on how public space use, and use of particular spaces, makes part of people's everyday lives.

C. Critical approaches to public space

Critical approaches in geography and urban studies have come to dominate scholarship on public spaces, as a way to evoke concerns over contemporary urban change [START_REF] Koch | Rethinking urban public space: accounts from a junction in West London[END_REF], including neoliberalism, 'class' struggles, social cohesion, public life, commodification, privatization and homogenization [START_REF] Carmona | Public space: the management dimension[END_REF][START_REF] Orum | Commong Ground? Readings and Reflections on Public Space[END_REF]. Within it, public space as an analytical category functions in three overlapping registers, as an ideal type for democracy and civil society; as a set of criteria for assessing existing spaces and processes; and as an arena of ongoing conflict and negotiation [START_REF] Koch | Rethinking urban public space: accounts from a junction in West London[END_REF]. These studies have been fundamental in exposing the political dimension of public spaces and their use and how they are epiphenomena of broader structural drivers. In that way, they have played a crucial role in denouncing certain negligence in regarding public space as a 'mere' design issue. Despite having achieved a rather acute ability for diagnostic critique, it seems to fall short when it comes "knowing what does work or how when it comes to intervening in public spaces" and to disregard "the demands placed on policy actors, decision-makers and actual spaces themselves" [START_REF] Koch | Rethinking urban public space: accounts from a junction in West London[END_REF].

D. Public policy studies

Another set of critiques to critical approaches has come from geographers engaging with methods and theories from public policy studies [START_REF] Fleury | Les espaces publics dans les politiques métropolitaines. Réflexions au croisement de trois expériences: de Paris aux quartiers centraux de Berlin et Istanbul[END_REF][START_REF] Dessouroux | La production des espaces publics dans la ville contemporaine. Enjeux, acteurs et logiques de gestion et d'aménagement dans trois communes de la Région de Bruxelles-Capitale[END_REF]. They have shown how the causal links between structural phenomena such as neoliberalism and the microgeographies of actual public spaces often overlook and downplay the explanatory power of concrete production processes. They have also challenged the Anglo-American bias of much of this work, thus joining recent pleas from the comparative urbanisms approach. Finally, they have also shown how analyses of public space production processes cannot be restrained to policy explicitly aiming at them (when there is any), but must also consider sectorial developments which impact them.

Work in collective action sociology and political science applied to urban policy and planning had long shown how decision-making is never linear and cannot be equated to the sole decisions of a political leader. Rather, they have shown how many solutions to apparently 'technical' or 'political' problems derive from complex interactions between myriad institutions, stakeholders and actors [START_REF] Idt | La construction des problèmes politiques de l'action publique à partir de questions techniques: analyse de projets d'aménagement urbai à Paris[END_REF][START_REF] Baptista | Practices of Exception in Urban Governance: Reconfiguring Power Inside the State[END_REF]; existing spaces, projects and management practices cannot be fully understood without consideration of these processes. The novelty of the aforementioned work by geographers [START_REF] Bourdin | La métropole des individus[END_REF][START_REF] Dessouroux | La production des espaces publics dans la ville contemporaine. Enjeux, acteurs et logiques de gestion et d'aménagement dans trois communes de la Région de Bruxelles-Capitale[END_REF], which directly inspires this proposal, is that they also analyze what is actually produced and the use dynamics therein, notably in [START_REF] Bourdin | La métropole des individus[END_REF], a concern often absent from more strictly sociological or policy studies.

IV. PROPOSED METHODOLOGY FOR THE RESEARCH

Following the brief presentation of some of the existing research, the wealth of possibilities for further investigations becomes evident. This particular research aims at contributing to re-placing the production of public spaces and their uses as an urban policy issue. It will do so through a comparative approach to three dissimilar processes of public space production, but which share two common characteristics central to this investigation: they are deployed at the scale of the city, i.e. there is a global approach to the public spaces within a given territorial jurisdiction; and use is one of the central concerns leading to their creation and implementation. The comparison of dissimilar processes in terms of policy scope, employed methods and formal outcomes is, because of this variety, expected to provide insight into the expected end result, the methodological framework.

While the agglomération of Lyon has become a paradigm in France on the inclusion of sociological surveys and thorough citizen participation in processes of public space production, Louvain-la-Neuve is a rare example of how a new town has explicitly conditioned urban form, land use and mobility planning to an idea of urban culture and conviviality rooted in public space use. Lisbon, in its turn, has since 2007 made public space, notably green areas, one of the pillars of its urban policy. Its concerns with stimulating use are evident in the renovation and installation of over thirty kiosks, mostly serving food and beverages, throughout the city in less than five years. The research's underlying assumption is that applied research leading to practical recommendations on how to produce public spaces which foster 'good' uses can go beyond localized project and management issues, without discarding their usefulness and appropriateness. The analysis will therefore address the issue at two levels of analysis. One, at the city level, will focus on the context framing the production process and on the overall approach to public spaces and the inclusion of questions of use. It will, then, imply the study of the sub-processes of program definition, conception and construction and management. The second level, that of a select number of specific public spaces, will study how the same sub-processes actually translate in particular moments of public space production, as well as existing uses and the relationship between processes and results. Existing uses will be confronted with the initial intentions of public space producers and with a set of criteria of 'good' public space use extracted from relevant literature. Methods for studying the processes at both scales will include interviews with intervening actors and analysis of documentation produced during said processes. Even though 'people can talk about their practices' [START_REF] Hitchings | People can talk about their practices[END_REF], the study of existing uses in specific spaces would ideally entail prolonged in-depth observations; however, practical limitations hamper its execution. Consequently, the overall description and assessment of uses will be derived from interviews with process actors and local agents. Short periods of observation will be undertaken to raise issues for discussion in the interviews and to analyze interviewees' claims. Fieldwork will alternate between case studies, allowing for gradually deeper surveys, nourished by interim analyses of gathered data, readings and cross-fertilizations between the different areas.

V. EXPECTED RESULTS

The research should provide detailed accounts of the different processes under study, which should in turn allow for three different sets of results, all of which will contribute to a methodological framework to produce 'well used' public spaces. Firstly, it should portray how different territories have tried to move away from technocratic, functionalist planning, through categories and in-depth illustrations of what 'taking use into account' might mean both substantively and procedurally. These should, at least, constitute a novel synthesis for urban design, planning and management. By tracing back the whys of public space policies and specific project choices in each case study, it should contribute to the growing body of literature on the production of the city and its public spaces, which seeks to connect macro-scale accounts of political economies to microgeographies of specific public spaces via the mezzo-scale of urban decision making, including political and technical actors. And, finally, by its tentative analysis of ongoing use dynamics, it should bring about notion of the 'effectiveness' of the different options made by urban administrations in each case study.

ACKNOWLEDGMENT

I thank my two supervisors, Alain Bourdin and Jorge Carvalho, for their precious input in defining this research project. I also thank Roxane de Flore and the reviewers for their comments on a previous version of the paper.

This research is financed by the Portuguese Foundation for Science and Technology (grant reference SFRH/BD/78852/2011) with national and ESF funds.