RING ROADS IN GREATER PORTO ALEGRE: would it be an effective sollution? 077 Cláudio Mainieri de Ugalde Keywords: Universidade Federal do Rio Grande do Sul - 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 – Brazil [email protected] Décio Rigatti Universidade Federal do Rio Grande do Sul - UFRGS Rua Carazinho, 146 Ap. 04 - Abstract 90460-190 – Porto Alegre – RS - Brazil Greater Porto Alegre, 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, Esteio and Campo Bom present the best results while Alvorada 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 077-03 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? 077-04 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 – Novo Hamburgo Rail Road, and, 1991 to 1996 afterwards, extended to the city of Taquara. 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 Cachoeirinha, 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 Canoas. 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 077-05 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, Sapiranga, Nova Hartz, Araricá, Parobé e Taquara could be better connected. Shoe industry is the predominant activity that takes place along the road.