RING ROADS IN GREATER : would it be an effective sollution? 077

Cláudio Mainieri de Ugalde Keywords: Universidade Federal do - UFRGS Transportation Décio Rigatti Metropolitan planning Universidade Federal do Rio Grande do Sul - UFRGS Spacial analysis Brazilian urbanization

Cláudio Mainieri de Ugalde Fundação Estadual de Planejamento Metropolitano e Regional – METROPLAN Universidade Federal do Rio Grande do Sul - UFRGS Rua Osvaldo Pereira de Freitas, 175 Ap. 1010 – 91530-080 – Porto Alegre – RS – [email protected] Décio Rigatti Universidade Federal do Rio Grande do Sul - UFRGS Rua , 146 Ap. 04 - Abstract 90460-190 – Porto Alegre – RS - Brazil , Brazil, has a different characteristic in relation to other [email protected] metropolitan areas. Its structure is highly marked by state and federal roads, specially, BR-116, which concentrates most of the regional movement, around 0,12 million vehicles a day, quite above its capacity. This chaotic situation makes society and public authorities think about ring road projects to be built distant and few connected to urban occupation. However, approximately 90 % of the flow corresponds to inner metropolitan traffic, and around 10 % is through movement. Hence, the present paper argues that this problem happens bacause of the way land subdivision process took place along BR-116 since its construction, in the 40’s. Connectivity, global and local integration are examined in metropolitan spatial configuration in order to discuss and evaluate if the new roads will be able to pruduce traffic flow changes in the metropolitan area. Case study results suggest that alternative routes to BR-116 must compete with it in terms of linearity, connectivity and global integration. Syntatic modelling described the metropolitan urban structure with accuracy and allowed simulation of different future configurational alternatives. Introduction In Brazil, many regional roads, constucted because of transportation demand between cities, became, after years, urban streets or avenues, due to occupation along them and where intercity transportation worked also as passenger urban transportation (Villaça, 1998 p.82). This process was responsible for the urban expansion of many brazilian metropolis. The structure and densification of new areas occured as a consequence of “natural movement”, described by Hillier et alli (1993), since, for many years, roads were the only way of intermunicipal movement and connection between subdivisions located along them.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

These centralities, with high traffic flow and economical activities concentration, became evident in Greater Porto Alegre, specially BR- 116, an important federal road and the main regional structure element and movement axis, which will be described ahead. Important attractors were built very close to it, like industrial districts, airports, universities, convention centers, generating a mutiplier effect of the concentrated movement, also described by Hillier (op. cit.). Nowadays, despite many decisions made to improve the capacity of BR-116, like the construction of viaducts, pedestrian passages, side lanes, more than 120.000 vehicles run this road a day, getting frequently congested in many parts. 077-02 Since the 70’s, authorities have been trying to build a set of highways, under a ring road concept, in order to create an alternative path to BR- 116, expecting to diminish its traffic flow and, as a consequence, decreasing negative effects like segregation, security, air and sound pollution over the urban space of metropolitan municipalities, which were seriously cut not only by the road, but also by the metropolitan rail road. We have argued, based on linearity principle, described by Hillier (1996), that metropolitan roads featured by certain axial fragmentation and low connectivity would probably have low integration values, although linking high density áreas and, therefore, wouldn’t “compete” with BR-116 to diminish its traffic flow (Ugalde 2002). With the conclusion of the axial map of metropolitan conurbation, it became possible to discuss, from the configuration point of view, the effects of the alternatives so far proposed to solve the problem, since approximately 90 % of BR-116 traffic flow is intra-metropolitan. In other words, 10 % of the traffic have origin and destination out of the metropolitan area. Therefore, the hypothesis we formulated earlier, can be verified in this case. In this context, this paper aims to examine, through Space Syntax theory and methodology, changes on the global accessibility of Greater Porto Alegre and the impact over the metropolitan spatial structure. The simulations correspond to the main alternatives so far presented by authorities, based on studies that did not take the configuration component into consideration. This paper is part of an ongoing research on the structure of the Metropolitan Region of Porto Alegre - MRPA, produced by Metropolitan and Regional Planning State Foundation – METROPLAN and Federal University of Rio Grande do Sul – UFRGS. The Role of BR-116 in the Spatial Organization of MRPA Metropolitan conurbation reaches 14 municipalities, although the Metropolitan Region of Porto Alegre – MRPA is officially instituted with 31. Some of them were included not for technical criteria but for political ones, in such a way that many cities are quite far from conurbation. It concentrates 36.40 % and more than 40 % of the Value Added, in only 3.4% of the territory of Rio Grande do Sul, the southernmost state of Brazil. It is located by Lake Guaíba and is cut by Sinos and Gravataí rivers, and other important creeks, which also influence its spatial configuration. Table 2 shows the rank of the municipalities according some socio- economic conditions through the local social extended index i, which takes into account the features of the municipalities regarding housing and sanitation, education, health and income. Porto Alegre, and present the best results while presents one of the worse results for the entire State.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Figure 1: Municipality limits in MRPA

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Table 1: Population of MRPA (CONURBATION) from 1991-2000

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

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Table 2: Local Social Extended Index The role of roads or highways in the conurbation process of MRPA (LSEI) of the municipalities was decisive, although its formation had started since the construction, of the MRPA conurbation – in 1875, of the Porto Alegre – Rail Road, and, 1991 to 1996 afterwards, extended to the city of . This rail road connected fluvial and terrestrial transportation which was necessary not only to the exportation of products made in Porto Alegre, but also for importation of goods used on the colonies founded in the north by german immigrants, that started to arrive in 1824. The first colony originates the city of São Leopoldo, which, for its importance, formed a kind of second pole of development in MRPA. During II World War, with the growth of the industrial sector, occupation around Porto Alegre and around the rail road stations increased, which originated the “dormitory cities”, because of the lack of jobs nearby. At this moment, the metropolitan segment of BR-116 was buit, with approximately 70 km between Porto Alegre and Novo Hamburgo, which is this paper focus. The highway, constructed by Federal Government, crosses Brazil from north to south and represents a fundamental factor in the social and economical development of the country. Due to the accessibility condition improved by the road, lands along it were intensively subdivided, what increased the demand for transportation. This situation became worse because of the lack of other connected streets with minimum linearity and pavement quality. It is the main pendular movement axis of the Region, achieving a 9.000 vehicles flow at rush hour. A similar process also occurred, in a lower intensity, with the roads RS-020 and RS-030, which were built before BR-116. Occupations along them formed the city of , emancipated from Gravataí in 1965. Down to the south, RS-040 also induces occupation, and most of land subdivisions along it, hardly connected among themselves, bring to this single road major part of the intra urban traffic of Viamão. During the 70’s, BR-290 was built, in the east/west direction, to function as a free-way to the coast. It was intended to be a segregated road with restricted accesses. Nowadays, it becomes clear that for its linearity and for the excelent assessibility that it brings to lands along it, some industrial, commercial and residencial developments have obtained pemission to connect it. After BR-116, BR-290 supports the highest traffic flows in MRPA. RS-118, constructed in the 80’s can be seen as the first perimetrical metropolitan road, connecting the coast to the northern part of the

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Region, avoiding . This is a very dangerous road because it is narrow, highly connected in such a way that pedestrian and vehicle crossing is indiscriminate and intense. Figure 2: Main roads, railroad and rivers in the MRPA

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The increasing importance of RS-240 can be noticed because of the great amount of occupation along it, not only because of the city of Portão, but also because this highway goes to a very prosperous industrial region in the northeast of Rio Grande do Sul. After the widening of RS-239, municipalities of the northern part of MRPA, , , Araricá, Parobé e Taquara could be better connected. Shoe industry is the predominant activity that takes place along the road. It has excellent traffic conditions. However, its flow is under its capacity. Finally, BR-386, represents the possibility of a more favorable link with agricultural areas in the northwest of the State, what brings, specially in the Canoas segment of BR-116, high traffic flow rates, mainly of trucks, part of the through movement in MRPA.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

In fact, as it can be observed in Figure 1, most of the roads converge directly to BR-116, what concentrates integration and reinforces traffic congestion.

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Figure 3: Proposed Solutions and Alternatives for Simulation Panaromic view of BR-116 in Canoas It is clearly noticed that public authorities and society as a whole aim Source: Metroplan to diminish traffic flow in BR-116. Many debates and studies have been done in the last decades. Some guidelines were partially planted as RS-118, BR-386 and BR-290. According to the political moment there is more or less emphasis in one or another solution, because of interests polarized between municipalities from the south or from the north of MRPA. In 2000, the Metropolitan and Regional Planning State Foundation – METROPLAN, completed a study called “Metropolitan Grid Complementation Program”, which aimed to “propose a structured grid compatible with densification, uses distribution, urban expansion and to the metropolitan spatial dynamics; to revive cities of the Region, reactivate accessibility to main centers; diminish travel times and order through movement along MRPA. Among specific goals we find: “seek a better intermunicipal grid and improve internal accessibility” (METROPLAN 2000 p.8). It resulted in the following guidelines: a) a free-way to the east of MRPA, starting in Porto Alegre and finalizing in Campo Bom at Municípios Avenue; b) the extension of BR-386 until RS-118; c) a metropolitan avenue, starting in Canoas until RS-239, in Novo Hamburgo; d) the Dique Avenue, from Porto Alegre to Alvorada; e) the extension of the Industries Avenue, an alternative link from Cachoeirinha to Canoas. In 2001, the Transportation Systems Laboratory – LASTRAN, from Federal University of Rio Grande do Sul – UFRGS, finished a study called “Analysis of alternatives for the problems of BR-116 saturation, Porto Alegre/Novo Hamburgo segment”; which consisted basically on

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution? an application of a transportation planning model (TRANSCAD), based on a Geographic Information System. MRPA was divided into traffic zones. The internal ones correspond to metropolitan municipalities and the external traffic zones correspond to regions outside MRPA. The road network is formed by the highways described above. Once concluded the origin/destiny research, and the flow score in specific locations, engineers calibrated the model and after comparing results of measured and modeled volumes, they considered TRANSCAD a capable instrument to predict future movement on the road grid (LASTRAN, 2001 p.5-10). Traffic volumes, on each road segment, for: a) 2001 demand and 2001 supply; 077-07 b) 2010 probable demand and 2001 supply; c) 2010 probable demand and total supply, which consists on free- way to the east, a free way to the west and extension of BR-386 until RS-118, through part of the east free-way; d) 2010 probable demand and partial supply, which consists on free- way to the east and extension of BR-386 until RS-118, through part of the east free-way; e) 2010 probable demand and partial supply, which consists on free- way to the west and extension of BR-386 until RS-118, through part of the east free-way; were transcribed to Table 3. It is important to say that, among others, these were the more representative scenes simulated by LASTRAN.

First of all it was verified that 10 % of the traffic have origin and destination outside MRPA (through movement); 31 % have origin and destination inside MRPA (internal movement) and 59% have origin or destination inside MRPA (mixed movement). Specific conclusions of LASTRAN are important to be registered, in order to be compared to conclusions of the configuration analysis: a) (...) the major effects occasioned by the construction of the two parallel highways to BR-116 (one to the east side and the other to the west side) will be on through and mixed movement. b) In BR-116, despite the legal speed limit being 80 km/h, it can be observed higher speeds, what can be an attraction factor for users (…); c) The increase of capacity must happen in the North/South axis, beginning with the capacity improvement of BR-116 (...) d) (...) results suggest that even the examined alternatives, in medium and long term (5 and 10 years), do not satisfy completely the expectation of significant flow or volume reduction in BR-116 (…) e) Regarding to the proposed grid, alternative to the east (free-way and BR-386 extension and widening of RS-118) have accesses and distances, more conditioned by occupation and consequently are better defined. On the other hand, options to the west aren’t well defined yet, because of the rarefied occupation limited by the river outflow basin. Lay-out, accesses, and distances related do BR-116 (that synthesizes travel times) are relevant for user’s decision. The closer BR-116 is seen, the more attractive it will become. f) (...) The more evident alternative for BR-116 flow reduction, particularly between Porto Alegre and Canoas is composed by an east free-way (segment between BR-290 and RS-118) BR-386 extension and widening of RS-118 although this group is not effcient if

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

detached from the east side of the ring. That is the reason why it was not simulated separately. g) Both west and east free-way, due to its similar features from BR- 386 and RS-118 up to north, show similar results on BR-116 reduction flow reduction. (…). Based in these results, the Roads Autonomous State Department – DAER, formulated the functional plan of an east free-way and a west free-way in 2002. Partial solution which has more chance to be planted corresponds to the southern part of the ring, composed by the east free-way 077-08 (segment between BR-290 and RS-118), the west free-way (segment Table 3: between BR-289 and BR-386) BR-386 extension and widening of RS- 118. It is has the lowest cost, compared to the others, and it permits Measured and modeled the rest of the ring to be built in the future. This solution has been traffic flows incentivated mainly by Canoas, due to its position in the MRPA.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Methodology for Configuration Analysis Configuration that represents the effective conurbation of MRPA will be analysed. So, it corresponds to 14 municipalities: Porto Alegre, Canoas, Esteio, , São Leopoldo, Novo Hamburgo, Campo Bom, Sapiranga, Estância Velha, Portão, Cachoeirinha, Gravataí, Alvorada e Viamão. Another important aspect is that, for the purpose of this paper, each simulation will be based on the present configuration of conurbation, which is not very different from 2001 (LASTRAN, initial reference of LASTRAN study). Alternatives that contain the ring roads, are considered as if they were built instantaneously with the projected viaducts and accesses. 077-09 Configuration analysis is based on Space Syntax theory and methodology, developed on Bartlett School of Architecture – UCL, London and also on concepts and methodology developed on Universidade Federal de Pernambuco - UFPE, which proposes a new linear representation of built environment through aggregation of axial lines, according to tested criteria and parameters (Amorim & Figueiredo, 2004) We will adopt it, because of the peculiarity of the present study, since we examine long axial lines which connect in wide angles, representative of roads, highways and free-ways. Global integration brief analysis will be illustrated (1) through integration core maps, due to limits of this paper extension. More relevant aspects will be remarked at the conclusion item. The following configurations will be simulated and analysed: a) Present configuration of conurbation; b) Present configuration with whole supply (complete road ring); c) Present configuration with east free-way and BR-386 extension; d) Present configuration with the west free-way; e) Present configuration with the east and west free-ways partially planted and BR-386 extension; f) Present configuration with the guidelines proposed by METROPLAN, as described above. Present Configuration Analysis Integration core evidences a linear structure marked by BR-116 (north/south) and BR-290 (east/west). RS-118 is also present indicating a tendency of change to a orthoradial system. In this way, RS-020 can be identified as a radial road that transmits integration to the central area of Cachoeirinha. In this direction we can also notice Assis Brasil Avenue, in Porto Alegre, bringing considerable integration to Sarandi quarter. Moreover, central zone and 4º District of Porto Alegre, which are the connection area of BR-116 and BR-290, have a quite integrated urban fabric, a few topological setps from these two highways, what can be contributing for its high integration values. It is clear the importance of Canoas for the spatial integration of MRPA and so it can be understood the great amount of movement not only in that BR-116 segment but also in most parts of the city. Besides being geographically central in the configuration, it has a regular grid highly connected to the highway, reinforcing pedestrian and vehicle flows.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Municipalities of Esteio and Sapucaia do Sul are totally conurbated, in such a way that it’s not possible to distinguish their administrative limits and differences on the continuous urban space. This part of the metropolis has a special condition because besides being connected to BR-116, it is also linked to RS-118, what brings it an excelent accessibility. It can be said that the metropolitan rail road caused in Sapucaia do Sul, the worse impacts of spatial segregation, but in some way compensated by the presence of RS-118. The foundation grid of São Leopoldo is also part of the integration core of Greater Porto Alegre. Internally highly connected and also with BR-116, it concentrates integration. Due to deformation after its limits 077-10 and the extension of some axis towards west side of BR-116, allowed Figure 4: by the viaduct over João Correa Avenue. These facts explain the Present Configuration (a), great concentration of activities and densities in this sector, as argued Complete road ring (b) by Hillier (1996a).

Novo Hamburgo is present in the integration core much more for 1º de Março and 7 de Setembro avenues and adjacent spaces than for its commercial area, what deserves better investigation. In this sector, BR-116 remains integrated, although with lower values if compared to southern segments. The same happens with Estância Velha, also belongs to integration core much more for Rincão quarter, well connected to BR-116, than

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution? for its commercial center, which is near the northwest limit of configuration. These are the main components of MRPA integration core. On the other hand, it is necessary to register the existance of sectors that although might present other integration levels in more local analysis, are, in fact segregated on the global scale. That´s the case of Alvorada and Viamão (Rigatti, 2002). There are some reasons for this evidence: a) Few connections with Porto Alegre, due to topographic situations, such as hills and Feijó Creek, which limits the two municipalities; b) Gravataí River outflow basin, to the north of Alvorada, corresponds 077-11 to an real edge of the system, so as the east side of the city, with the end of urbanization; c) High axial fragmentation and descontinuity in Viamão and low ringness at Alvorada spatial system. In sequence, we will examine modifications on the metropolitan urban structure caused by supply increase (Figure 4a). Present Configuration with Whole Supply - Complete Road Ring The participation of the whole road ring on the integration core becomes evident. However, the east free-way has more axis with high integration values. West free-way shows higher integration values in the segment between BR-386 until the accesses to Sapucia do Sul e São Leopoldo. There is a significant increase on the integration of the central area of Cachoeirinha, Sarandi quarter, in Porto Alegre, and on the east part of Canoas. Frederico Ritter Avenue, in Cachoeirinha together with the first segment of the east free-way will concentrate most of the integration in Canoas/Cachoeirinha conurbation. The importance of the necessary extension of BR-386 until RS-118 is evidenced, the same way as the increase of integration of RS-020. In this alternative, central areas in São Leopoldo and Sapucaia do Sul have lost integration. In the visual analysis, BR-116 seems to maintain its importance all the way long. Although it is not evident in the integration core analysis, when we verify global integration, the existence of the east free-way causes an integration gain in Sapiranga, in the east side of Campo bom and also for RS-239 (Figure 4b). Present Configuration with East Free-way and BR-386 Extension The effect of this alternative is similar to the last one, regarding to the integration core. However an increase of integration on the east free- way is transmitted to Alvorada through RS-118 (Figure 5a). Present Configuration with the West Free-way According to the qualitative analysis, the construction of a west free- way doesn’t provoke significant modification on the present integration core of Greater Porto Alegre. Even the west part of Canoas remains very similar (Figure 5b). Present Configuration with the East and West Free-ways Partially Planted and BR-386 Extention This alternative adds integration to a considerable part of the urban area located among BR-116, BR-290 and RS-118, with some loss to

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Cachoeirinha, once many transversal axis to the north of Avenue, in the first part of RS-020, had decayed. Figure 5: On the other hand, central areas of Esteio, Sapucaia do Sul and São Present Configurations Leopoldo maintain their importance, as well as BR-116 (Figure 5c).

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Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

Present Configuration with the Guidelines Proposed by METROPLAN The east free-way, proposed by METROPLAN, has a different course in the northern part, compared to the other alternatives. It connects Novo Hamburgo through Leopoldo Petry Road. It appears as a well integrated axial group. However it doesn’t bring integration to Sapiranga and to the east side of Campo Bom in the same proportion that when connecting directly with RS-239. This alternative also aggregates integration to a considerable part of the urban area located among BR-116, BR-290 and RS-118, as well as it keeps São Leopoldo at the same condition of good integration on 077-13 the configuration. However Sapucaia do Sul decreases its importance. On the other hand there is an integration deficit on Primavera quarter, in Novo Hamburgo and on Rincão quarter in Estância Velha. Integration in BR-116, not only to the north of Sinos River but also to the south remains almost the same as in the present configuration. The Dique Avenue, connecting Porto Alegre to Alvorada in better conditions, appears as relevant to the global integration of MRPA, and brings integration to a sector that have been always segregated not only globally but also locally (Figure 5d). Local Integration Analysis Local integration, in this paper, is examined considering the mean depth radius of the system (RR), according to Amorim @ Figueiredo (op.cit). The configuration processed by the software Mindwalk (Figueredo, 2004) reveals captured the local integration of municipalities with accuracy. After that we took the same procedure with complete roads suply and verified that Spiranga, Novo Hamburgo, Campo Bom, Estância Velha and Cachoeirinha had thier local integration affected. In general the central commercial areas diminished their integration values. Akkilies van Nes (2001), contributed to the discussion of ring roads, examining impacts on four city centers in England where this solution was implemented. He concluded that the way in which the ring road connects the urban grid is determinant of retail location. Although Nes has investigated impacts on the pattern of shop location in more detail, his general conclusion do not contradict a general overview of movement changing in these municipalities, with consequences to commerce and some services. The ring road, in a general view, tends to concentrate integration also at a local level, because they remain well integrated at RR radius (radius corresponding to the mean depth of the system). Conclusions Space Syntax theory and methodology combined with the aggregation lines model were extremely useful to capture spatial relations and configurational properties, necessary to this debate. The correlation between global integration and measured traffic flow was r²=0,6245, what indicates that this proportion of metrpolitan movement is explained by spatial configuration. Specifically, the axis that belog to BR-116 correlated to measured flow up to 0,997 (r²). LASTRAN Study was the first one, we had the chance to know, that made a scientific approach to the BR-116 problem. We don´t mean to doubt its results. In fact, important considerations about traditional transportation models were made by Penn et alli (1998). We just want

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

to highlight some of its conclusions, which match the main aspects brought by the present paper. One of the most important ones, is that the ring road won’t be able to reduce significantly traffic flow in BR-116. We verified, through the configuration analysis, that, according to global integration values, the relative position of the proposed road ring will not contribute to diminuish its traffic volume. Although the roads that compose the ring (east free-way, west free- way, RS-118 and BR-386 extension) participate on the integration core, or even if some of their component axis might present higher 077-14 values than the axis of BR-116, it doesn’t mean that there will be a Table 4: descrease in BR116 traffic flow. Variation of Rn in BR-116 Table 4 shows the increase of integration values of the axis of BR-116, segments in each one of the simulated alternatives.

In fact, it is a configurational matter that cannot be analysed only in terms of metropolitan road grid, but of total street grid, because, as argued by Hillier (1996), global integration is the result of local decisions. The decisions of relative position of each space in the system are taken every time, by private and public agents, when making or approving land subdivision projects. Certainly, in MRPA, the common lack of articulation between sudivisions influenced the BR-116 movement, for depth gain they provoked in some parts of configuration. Table 5: Variation of connectivity according to highway axis

The system mean integration increase, with the whole or partial supply of roads in the ring, represented an accessibility gain. However it was not sufficient to redistribute integration. The reason, we argue, regardas to low connectivity of the ring and the fact that its axial fragmentation is higher than the ones in BR-116’. If, on one hand, Metropolitan Avenue, proposed by METROPLAN, is well connected, on the other hand, it does not have sufficient linnearity in order to compete with BR-116. That’s why axis along it don’t reach expected integration values. When LASTRAN Study concludes (b) that the possibility, of vehicle drivers. to cross legal speed limits (80 km/h) in BR-116, can be an attraction factor, we understand that this is a question of linearity

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution? perception. Also, when engineers in LASTRAN, said that the closer the alternative path is to BR-116, the more attractive it will be, we understand that this regards much more to topology than to metric distances. We argue, then, that ring roads issues require a deep knowledge on the spatial system where they are to be included. Quantity and location of connections are crucial what suggests that segregated free-ways shoud be avoided. Segregated roads planned to run away from urbanization wouldn’t be free of occupation along their margins, what would increase its connectivity level, with tendency to traffic increment, in case there are no alternative routes topologically nearby. This kind of paradox , or 077-15 “circular cause problem”, so called by Villaça (op.cit.:82), shall finish in the acceptance of connectivity and integration as fundamental elements for a functional city and a intelligible space. As we can see, planning agents in METROPLAN proposed not only the east free-way, or the Metropolitan Avenue, but also the extension of BR-386. However, BR-386 extension was not planned to be an integrator space of a part of the urban fabric in Canoas: Guajuviras, a highly segregated quarter with high indexes of criminatity. In this way, an opportunity will be lost. Ring roads don’t have to be exclusively traffic channels, they can represent important urban integrator elements, carrying other infrastructures and creating economical opportunities and social development. Based on potential effects over metropolitan urban structure, we verified, among the tested alternatives, that the east free-way, linked up north to RS-239 and the extension of BR-386 would be the guidelines that probably would better improve a cost/benefit relationship towards integration in MRPA and contribute for BR-116 traffic decrease in the future, mainly for the following reasons: a) with the tendency of urban expansion to the east, east free-way would have the chance to increase connectivity and then compete with BR-116; b) the west free-way shows lower integration values, has important environmental restrictions to its construction, and this amount of finantial resources could be used to improve connectivity in the east free-way; c) the east free-way brings more global integration to populated municipalities, specially Sapiranga, Campo Bom and Alvorada. References Figueiredo, L., 2002, Mindwalk, version 1.0, space syntax software, Available at: http://www.mindwalk.com.br Figueiredo, L., Amorim, L., 2005, “Continuity Lines in the Axial System”, A. van Nes (Ed.), Proceedings, 5th International Space Syntax Symposium, TUDelft, Techne Press, vol. 1, pp. 161-174. Hillier, B., Penn, A., Hanson, J., Grajewski, T., Xu, J., 1993, “Natural Movement: Or Configuration and Attraction in Urban Pedestrian Movement”, Environment and Planning B: Planning and Design, 1993, volume 20, p. 29-66. Hillier, B., 1996, Space is the Machine, Cambridge University Press, Cambridge. Hillier, B.; 1996a, “Cities as Movement Economies”, Urban Design International, 1 (1), 49-60.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007 Ugalde, Rigatti; Ring Roads in Greater Porto Alegre: Would it Be an Effective Solution?

LASTRAN, 2001, “Análise de Alternativas para os Problemas Advindos da Saturação da BR-116”, Trecho Entre Porto Alegre e Novo Hamburgo, Porto Alegre, LASTRAN. METROPLAN, 2000, Programa de Complementação da Malha Viária Metropolitana, Porto Alegre, METROPLAN. Nes, A. van, 2001, “Road Building and Urban Change”, J. Peponis, J. Wineman, S. Bafna (Eds.), Proceedings, 3rd International Space Syntax Symposium, Atlanta. Penn, A., Hillier, B., Banister, D., XU, J., 1998, “Configurational Modeling of Urban Networks”, Environment and Planning B: Planning and Design, volume. 25, p. 59-84. 077-16 Rigatti, D., 2002, Loteamentos, Expansão e Estrutura Urbana, Porto Alegre: PROPUR/UFRGS. Ugalde, C. M., 2002, “O Parcelamento do Solo na Região Metropolitana de Porto Alegre; Efeitos das Decisões Locais no Espaço Urbano Regional”, Dissertação de Mestrado, Universidade Federal do Rio Grande do Sul, 2002. Villaça, F., 1998, Espaço Intra-urbano no Brasil, São Paulo, Studio Nobel.

i. It is important to remark that some analysis may become difficult to be understood due to the form of representation of the integration maps. Black and white maps with the integration core for large systems as a metropolitan conurbation do not capture the variations in the levels of the integration as the color maps do. The visual analysis in this paper was based on the color maps.

Proceedings, 6th International Space Syntax Symposium, İstanbul, 2007