Contemporary Decentralized Development of a Centrally Planned Metropolis: The Case of Budapest

Thisstudyexaminesthe changesundergonebyurban centerswithinGreaterBudapest’sextensionarea,which wasannexed to the capital of Hungary in 1950, and which is, with minor modifications, equivalent to the outer zone today. The arti‐ cle compares the development methods of two different political systems: state socialism (i.e., the communist regime) between 1950 and 1990, and post‐socialist capitalism after 1990. Over a longer period, the urban development of Budapest has made a long but circular journey from decentralized to a decentralized–disjointed socio‐spatial development system, passing through a centrally‐planned communist era between 1945 and 1990. Nevertheless, closer examination of this process reveals that several paradigm shifts took place in the design methodology, which was strongly influenced by socio‐economic changes. These shifts, layered upon the inherited structure, as well as the neglect or preference of dif‐ ferent systems, caused great differences in the development histories of centers on the outskirts. Therefore, we have set up a development typology for the centers on the outskirts by summarizing the planning history at the city level. Based on how well the center was able to incorporate itself into the larger metropolis since 1950, we have distinguished the follow‐ ing development models: the metropolized, the transcript, the rehabilitated, and the urban village model. This typology is extended to include new urban centers that formed during state socialism (between 1950 and 1990) and post‐socialist capitalism (since 1990).


Introduction
The main objective of our study is the comparison of the state socialist-centralized (between 1949 and 1989)-and the post-socialist-decentralized (from 1990 onwards)-development processes within the capital of Hungary, Budapest. As a starting point, we adopt a theoretical perspective that helps to situate our study in the international literature, listing the most important urban theories related to the topic. Then, to make the local spatial, political, and economic conditions clear, we place Budapest in a larger context, that of Central and Eastern European (CEE) during state socialism and after the 1989-1890 transition period. After that, we briefly introduce the reader to the planning history of Budapest, focusing on the changing concept related to its urban centers. Lastly, we evaluate and classify the results of these development policies to gain a professional overview of the actual system of the centers of Budapest.
Based on primary sources and international scientific literature, the aim of the study is to compare the actual system of centers to the traditional, inherited structure (as it was in 1950) through an understanding of the development methods of the two political systems: state socialism, between 1950 and 1990 (influenced by modernism), and post-socialist capitalism after 1990 (that is considered to be contemporary). The central hypothesis of this article is that, from a historical perspective, the urban development of Budapest has taken a long, but circular journey from decentralized to decentralized-disjointed socio-spatial development by starting from a decentralized, traditional typology (with many different cities and settlements having their own development policy), passing through a centralized, fast modernization of the pre-and interwar period, to then undergo a centrally planned state-socialist phase between 1945 and 1990 (in the spirit of late modernism) and arriving at the recent post-modern, contemporary, decentralized type of development with constantly changing influences of central governance (e.g., EU, city, and state). As a result of changing policy and position of centers, as well as the shifting historical, social, and environmental framework, we have established a development typology for the centers on the outskirts through the summary of the planning history on the city level.
After 1990, Budapest underwent the socio-spatial changes typical of the post-communist Eastern Bloc. First, the disintegration of the centralized power for 40 years and the change to neoliberal capitalism resulted in uncontrolled suburbanization and the exploitation of vacant urban peripheries. Then, after the economic crisis, the undertow of the population concentrating in the center could be observed. Keresztély (2002) claims that Budapest was a "winner" in this political-economic transition period; however, this further widen the gap between the capital and the rest of the country. Today, the 1950 extension area of Budapest is not the main targeted area of inner migration. Additionally, some peripheral districts have faced dramatic shrinkage (Hungarian Central Statistical Office, 2021). In the past decade, with the revitalization of former town centers-now mostly subcenters in a metropolis of two million-the revival of local communities and identities, conflated by centralized planning in the past, can be experienced. Nevertheless, due to the limited power of the city government, there are huge disparities and inequalities among the districts (OTP Jelzálogbank, 2021, p. 9).

Center
To support our argumentation, a brief explanation of the notion of city center is crucial. First, based on the arguments of widely accepted scholars (Blumenfeld, 1949;Hall, 1998;Jacobs, 1969;Lynch, 1961;Montgomery, 1998), it must be stated that cities cannot exist without a center. The most important socio-spatial characteristics of centers are, at the same time, the essential motivators of making a city, and these conceptual (and ideological) factors-market and competition, node and pole, faith, power, security, mixture, and identity-are the determinants of center creation, maintenance, and rehabilitation. Still, centers do not evolve if only a few criteria are present, since those are only mono-functional patches within the urban structure (Losonczy & Orbán, 2022). Subcenters became indispensable in modern, urbanized polycentric cities. Roncayolo (1966) claims that subcenters are the "democratized" forms of centers, which means that forming subcenters brings decision-making closer to people.

Timing
In our study, we will apply the distinction of traditional, modern, and contemporary city models, because widely accepted international theorists-motivated by ideological reasons-use this trichotomy based on historical epochs (Lynch, 1961;Mumford, 1961;Price, [ca. 2001];Shane, 2011). In general terms, traditional, monocentric cities do not tend to grow beyond a walkable size, which means the city itself is the center. It is believed that the separation of activities and motorization can be linked to the beginning of the modern epoch. Urbanization signifies an immense population and territorial growth thatsupplementing the traditional city centers-requires the constitution of multiple centers in a city, whose structure becomes polycentric. Contemporary cities can have multiple, functionally thematic centers (and subcenters) that exist in constant correspondence and have networked connections. These city models, which are center structure models as well, are frequently used in planning practice and policymaking. Yet, this trichotomy is not universal, and it contains simplifications and stereotypes (Losonczy & Orbán, 2022).

Interrelation of Center Models and Spatial Structures
Contemporary researchers (Barabási, 2002;Batty & Longley, 1994;Shane, 2011;West, 2017) frequently refer to the geographer Walter Christaller, who outlined the ground-breaking central place theory in 1933. He argued that systems, subsystems, and sub-subsystems are similar, which assumes a hierarchical, fractal-like city structure. We argue that a hierarchic approach is still necessary for urban planning and studies, especially in urban policy and governance. In planning theory and practice, spatial structure models depict the distribution of urban centers on different levels. This includes Bertaud (2013), who depicts four spatial structures influenced by the pattern of commuting trips between centers. Bourdeau- Lepage and Huriot (2002) claim that metropolization is the concentration of emerging metropolitan functions which seek to be located centrally. They argue that the process of metropolization depends essentially on agglomeration because it occurs only above a minimum threshold of urban agglomeration forces. This cumulative process results in a spatial re-composition, usually accompanied by the intensification of the urban fabric.

Regional Context: Central and Eastern Europe
The 1989-1890 regime change has brought about far-reaching socio-economic and urban development changes in all post-communist countries, including the metropolitan areas of all CEE transition countries. However, these abrupt socio-economic and spatial changes in CEE cities have not been uniform (Gentile et al., 2012), according to-and affected bythe specific national developmental path they have taken, even within the so-called "socialist area and camp." Nevertheless, we have to accept that the capital cities and new industrial cities under communism were planned and designed to materialize rapid modernization and industrialization, all the while symbolizing progress in the achievement of ideological-political goals such as a just and classless workers' society. Characteristic socio-spatial urban symbols-and socialist remnantsare represented by new spaces and buildings, for example, the prefabricated, multi-apartment housing estates in CEE capital cities, mainly on the outskirts. Although the idealized, full-fledged "homopolis" (Gentile et al., 2012, p. 293) of the socialist dream was never realized, the socalled "homopolitanization" (Gentile et al., 2012, p. 293) agenda could be witnessed in each CEE country under socialism. Contrary to that, after the 1989-1890 regime change, these cities moved rather in the direction of the "heteropolitanization" (Gentile et al., 2012, p. 294), journeying along different political, institutional, administrative, and socio-economic urban development paths.
The book entitled The Socialist City, published in London in 1979, was one of the firsts to undertake a general description and spatial model of communist urban areas, trying to establish a simplified model to describe the structure of these cities (French & Hamilton, 1979). Hamilton's model uses eight zones. Within the small inherited inner area, he differentiates the historic core from portions that originated in the capitalist period before World War II. The large communist outer urban area is composed of a transition zone, socialist-realist housing from the 1950s, modern residential districts from the 1960s and 1970s, an open or planted isolation belt, an industrial zone, and the countryside.
The model by Sýkora (2009), a researcher from Prague, presents four categories: the center, which can be historic or not; the inner city; the housing estate as an independent unit; and the periphery (in the socialist version) or the suburb (in the post-socialist version). Yet, as Bertaud (2004) summarized, "CEE cities are, after all, more European than socialist," although he highlighted some key spatial issues in relation to the actual problems of European post-communist cities: the lack of retail and service space in the city center, the huge inherited social-ist residential areas, the used or unused industrial land located close to the city center, and, lastly, the weak and poorly maintained urban infrastructure.
If we want to use a schematic model for our contemporary cities, it is enough to differentiate three parts: (a) the inner city, the basis of the city's identity; (b) the transition belt, the heterogeneous area with inherited and contemporary parts; and (c) the outer zone, halfway between rural areas and the suburbs, including former independent settlements, edge cities, housing estates, residential pavilions, industrial or agricultural land, green areas, etc. (Benkő & Kissfazekas, 2019).

Research Methods
Our analysis focuses on the planning and the development of the centers in the 1950 extension area-which is almost equivalent to the actual outer zone, defined in 1994-up to the present day. The article is based on a review of literature, analysis of documents related to Budapest policy documents, and data collection both historic and contemporary. The essence of the methodology is to describe the spatial changes over time. The special value of the present study is that it analyzes the spatial changes over a large time span instead of a single period. This method is particularly suitable for analyzing environments that have undergone similar economic policy changes, especially in post-socialist CEE countries.
This comparative analysis covered six general development plans on the Budapest level. Three of them were prepared during the state-socialist period in 1960, 1970, and 1980. The three others occurred after the political and economic change in 1994, 2003, and the current one from 2013. The series of maps depicts the center structure of these strategic planning documents revised every 10 years (see Figures 1 through 8). The summarizing table (see Table 1) shows changes in centrality statusas defined in these six plans-for all the urban areas that were designated as centers since 1950, even if only once.
Due to the continuous methodological changes, the names and classification of the centers at different levels were often modified. Therefore, for sake of simplifying and unifying the different terminology used in Budapest's development plans (e.g., main center, subcenter, local center, commercial center), we used a coding system in the summarizing table (see Table 1) and on the maps (see Figures 1 through 8). The C1 designation indicates the most important centers that are involved in the entire operation of the capital city. The mid-level C2 label is applied to centers that are important to a given district or multiple districts. The notation C3 is introduced when the given center is only significant for the neighborhood.

An Explanation of Budapest
Budapest-at least the traditional city centerdeveloped quite organically until the end of the 18th century. When the three historically distinct parts or traditional settlements (Buda, Óbuda, and Pest) united in 1873, Budapest became the capital city of Hungary (more precisely the Hungarian Kingdom within the Austro-Hungarian Empire). Nonetheless, the political-economic development period between 1867 (the beginning of the Austro-Hungarian Monarchy) and World War I was unprecedented both from the nation's and the capital city's point of view. There was fast industrialization, modernization, and urbanization all at the same time. Budapest became the second largest city within the Empire-after Vienna-attracting economic capital and generating many new industrial investments. This required human capital and an increased labor force augmented from rural areas. The number of industrial enterprises more than tripled between 1890 and 1910 (from 365 to 1,300), employing more than 200,000 people, thus establishing one of the most dynamically developing industrial centers in CEE (Kardoss, 1999, as cited in Kiss, 2007, p. 149).
This fast socio-economic urban development and the construction works of Budapest were centrally planned, managed, and executed by the Communal Planning Office of Budapest (Fővárosi Közmunkák Tanácsa) between 1870 and 1944 (Sipos, 2009). The construction of the railway lines and the regulation of the riverbank supplied an impetus for the industrial and residential expansions around Little Budapest. At the turn of the 19th century, the built-up area and the population of the settlements around Budapest increased exponentially. Also, a contiguous built-up area was created along the city boundary (Kocsis, 2008). This is how the so-called "commuter villages"-reminiscent of garden cities but inhabited by lower-income workers and lacking ade-quate physical and social infrastructure (Kovács & Tosics, 2014)-emerged. The idea of the Greater Budapest Plan (Bárczy & Harrer, 1908) emerged at the beginning of the 20th century with the aim of shaping it into the capital city of a prosperous Central European country, home to six million people. Historically, Budapest occupied a central position within the Hungarian Kingdom, but its role changed after World War I when the Austro-Hungarian Monarchy collapsed. Due to the Trianon Treaty, Hungary lost more than 67% of its territory, and roughly 33% of its population (Kiss, 2007, p. 149).
This socio-spatial central position was strengthened during the communist regime, coupled with the inherent characteristics of top-down central planning, characteristic of the whole political-economic system led by the communist party, and that included Budapest, too. The largest socio-spatial urban development change was politically decided in 1950 when-after many territorial modifications after World War I, influenced by political reasons-23 former distinct settlements in the agglomeration area, larger towns, and even smaller villages were "added" to Budapest, forming the present 23 districts. At the time of the extension, seven of them were important towns with developed centers (Budafok, Csepel, Kispest, Pestszenterzsébet, Pestszentlőrinc, Rákospalota, and Újpest), while the other 16 were simple villages (see Figure 1).

1950-1990: State Socialism
The state socialist regime after 1950 promoted the planned economy and applied strict control over the allocation of human activities in space (Sýkora & Stanilov, TOWN (1949) VILLAGE ( [1960][1961][1962][1963][1964][1965][1966][1967][1968][1969][1970][1971][1972][1973][1974][1975], which allocated the resources to well-connected empty blocks near the city center-i.e., to the transition zone of the city. This plan represents a monocentric concept, although the targeted areas can be referred to on the basis of land-use plans and texts (see Figure 2). The aim of the plan-concerning the extension area-was to develop the so-called "workers' districts" (Kissfazekas et al., 2020;Preisich, 1998), whose centers became prioritized urban areas (C1). During state socialism, following the example of most post-war European cities, the large housing estates of Budapest were realized on the periphery of the city (Sýkora & Stanilov, 2014); therefore, the focus of development gradually shifted to the 1950 extension area. The General Development Plan accepted in 1970 (Budapesti Városépítési Tervező Iroda, 1970) increased the number of large housing estates (Benkő, 2015) that were positioned on the periphery. Yet, most of them were not defined as centers, since the concept envisioned a radial development along existing and planned traffic lines (Szabó, 2020), and centers were defined as transport hubs rather than accumulations of urban activities (Kondor & Szabó, 2007). Nevertheless, after the centralization in 1960, the 1970 plan elaborated a polycentric concept with a three-tier hierarchy (see Figure 3).
Besides the historic core, it designated six subcenters (C1, városrészközpontok) that were already urbanized areas of "modernization" and intensification, but only two of them were located on the outskirts (Újpest and Kispest). Nine traditional district centers (C2, kerületi központok) were listed to adopt medium-level services, six of them lying on the outskirts. Since the concept was extended to the agglomeration, most suburban centers (C3, településcsoport-központok) were designated there, except for two of them.
The revised General Development Plan submitted in 1980 (Budapesti Városépítési Tervező Iroda, 1980) contains even more greenfield development areas to enhance the construction of large housing estates, but these areas do not appear on the city-level spatial structure concept, because most of them were only provided with basic services (see Figure 4). The aim of the 1980 Plan was to consolidate resources and to simplify the 1970 Plan. The task of rehabilitation was postponed, since the district centers were wiped out, although three of them were appointed as subcenters (C1, városrészközpontok). To mitigate the suburbanization movement that had already begun by the end of the 1970s, the concept decreased the number of suburban centers (C3, településcsoport-központok).

After 1990: Transition Period
After the system change in 1990, the sudden leap into free-market capitalism led to the profound socio-spatial reorganization of urban landscapes all over the former Eastern Bloc, and most metropolises were affected by the so-called postsocialist suburbanization (Sýkora & Stanilov, 2014). Budapest went through a rapid metropolization that altered core-periphery relations within the country (Egedy et al., 2017). In the peripheries of most CEE cities, an increased supply of vacant land became available, aided by the flexible re-zoning adopted by most suburban municipalities (Sýkora & Stanilov, 2014). Instead, districts within the outskirts could only provide development areas on a limited scale.
In this manner, a period of strong suburbanization commenced (Kovács & Tosics, 2014). As a result, Budapest lost 300,000 residents between 1990 and 2010. However, since 2008, the city has been recording a net influx again (Hungarian Central Statistical Office, 2021).
According to the 1990 Act on Local Government, a complex, multi-tier-but quite fragmented-local governmental and administrative system was created in Budapest including 23 autonomous local (district) governments with the coordinative Budapest Municipality above them. Due to this new double-level governance system, every district within Budapest became much more independent, having the right to make their own decisions about land policy and urban developments. Yet, this weakened the power of the municipality on a city-wide scale (Kovács & Tosics, 2014). The urban planning system of Budapest became multi-level in both strategic and regulatory fields, but the preparation of the land use and structural plans remained under the authority of the capital. The aims of the capital to control territorial extensions collided with the imperative of the districts to create opportunities for development that became promoters of growth (Sýkora & Stanilov, 2014). Along the new highways (M3, M1, and M5), economic growth poles of agglomeration emerged, and large commercial and logistics centers were created in previously vacant agricultural areas (Dövényi & Kovács, 2006). The construction of the-still unfinished-M0 highway fostered the installation of plazas (shopping malls) and hypermarkets at highway junctions.
Since the submission of the first General Development Plan in 1994 (Budapesti Városépítési Tervező Iroda, 1994), Budapest has employed a model similar to that of French and Hamilton (1979)-a schematic five-zone model with three basic elements that may be generalized across Europe: the historic core, the transition belt, and the outer area. The other two components reflect natural attributes that modify the first three categories: the Danube area and the hilly area. The strategy separates the interests of the whole city and the districts, while accordingly defining a three-level center hierarchy (see Figure 5). Enhancing the diversity of the areas, this plan aimed to define the different strategic goals for each zone. The outskirts of Budapest, which covers the 1950 extension area with minor territorial revision, was considered an "area directly connected to the agglomeration." In this way, all the subcenters (C1, mellékközpont) were positioned in the transition belt-i.e., at the border of the outer zone. Nevertheless, the new plan defined five "sub-subcenters" that are the extensions of subcenters (C2a, alközpont), several outskirts' centers (C2b, elővárosi központ), and hilly zone centers (C2c, hegyvidéki központ). In addition, the plan depicts seven "city gates" (városkapu) that were supposed to be the sites of extensive developments, taking advantage of the highways and the planned M0 highway.
The General Development Plan of 1994 was replaced by the new Urban Development Concept that was integrated into the Structure Plan (Településszerkezeti Terv;Budapest Főváros Városépítési Tervező Kft, 2005). The five zones established in 1994 remain, but the planned central system of Budapest changed significantly. According to this plan, there is no hierarchy among centers; thus, every center is at the same level (see Figure 6). The ones designated "subcenters linked to the city center" (C1a, városközponthoz kapcsolódó városrészközpont) were meant to function as gates of the city center and were mainly traffic junctions. The ones termed "subcenters with intermodality" (C1b, intermodális szerepkörrel fejlesztendő városrészközpont) lay in the transition zone between the historic core and the outskirts or the hilly zone.  The plan, again, uses a triple division (see Figure 7). All the subcenters (C1, mellékközpont) are positioned in the transition belt. Subcenters require a significant capacity for traffic connection; thus, they can have a sectorial influence on agglomeration, and most of them also function as intermodal hubs. The document distinguishes local centers by catchment area. "Local centers on a  Urban Planning, 2022, Volume 7, Issue 3, Pages X-X higher level" (C2, kiemelt jelentőségű helyi központ) are defined as district centers or traditional community centers that have a major capacity of connectivity to the city. The ones termed "local centers on a lower level" (C3, jelentős helyi központ) are defined as neighborhood centers with only basic services that have no effect on the whole city.

Comparison of the Original and Present Structure
A comparison of the situation in 1950 and the plan for 2013 shows the spatial displacement of each center, the losses of position, and the gains as well (see Figure 8) 1949, 1960, 1970, 1980, 1990, 2001(Hungarian Central Statistical Office, 2021, so that the extent of urbanization-or in some cases, shrinkage-can be traced. From one aspect, the table reflects the progress of changes and movement (as shown in Figure 8), while it also delineates the characteristic typologies of center change, on the basis of which six models can be distinguished. The models were not only set up based on the movement of the centers, but we also took into account population changes (Hungarian Central Statistical Office, 2021) and neighborhood real estate market data (OTP Jelzálogbank, 2021), which are good indicators of economic performance  and popularity. In this way, the models show not only how outskirts centers have strengthened, weakened, or shifted, but also how well they have been able to become part of the metropolitan center system.

The Metropolized Model
These centers are Újpest, Pesterzsébet, Csepel, Pestszentlőrinc, and Budafok. Before 1950, the representatives of this typology were already important town centers. Most of them (except for Csepel and Budafok) emerged right on the border of the capital after 1873, the year that Little Budapest was unified. Between 1950 and 1990, they were focal points of communist urbanization since they were intensified with upper-level institutions. All of them became the sites of modern mass housing construction, but these were not implemented through total demolition. Some parts of the historic urban fabric remained, and the large-scale extension coexists with the original structure (Losonczy et al., 2020).  1950-1989 1990 onwards 1950 1960 1970 1980 1994 2003 2013 Year   1950-1989 1990 onwards 1950 1960 1970 1980 1994 2003 2013 Year After the system change in 1990, representative contemporary institutions were realized. All these centers are the administrative centers of the given district. They can be characterized by good status and good connectivity (Benkő et al., 2017). In terms of amalgamation to the greater metropolis, these are the most successful centers. They represent integral parts of the city.

The Transcript Model
These centers are Kispest, Rákoskeresztúr, Mátyásföld (Reptér), and Albertfalva. In contrast to the previous typology, these traditional village/town centers wereexcept for some symbolic buildings-totally demolished and replaced by modern mass housing estates. This resulted in a loss of character and a rupture in the urban fabric (Losonczy et al., 2020) as well as underdeveloped central functions. Since 1990, contemporary developments have avoided these areas, and stagnation is visible. Instead of being symbolic and/or administrative centers, they function today as residential neighborhood centers, not integrated into the larger, metropolitan structure.

The Rehabilitated Model
These centers are Budatétény, Soroksár, Mátyásföld (Erzsébetliget), Sashalom, and Nagytétény. Before 1950, they were village centers that emerged in the industrial-ization period after 1873. Thus, their original character is reminiscent of garden cities. In the era of state socialism, they were neglected areas on the city level, because central planning concentrated on "workers' districts." After the system change, these centers were developed by the construction of upper-level services, mostly promoted by the district municipalities. Consequently, urbanization through contemporary developments was successful; and, as a result, they became important on the level of the city as well.

The Urban Village Model
These centers are Pesthidegkút, Békásmegyer, Pestújhely, Cinkota, Rákosliget, Rákoshegy, Pestszentimre, Rákosszentmihály, Rákoscsaba, and Rákospalota. Like the previous typology, these traditional village centerswith the exception of Rákospalota-were neglected by central planning authorities between 1950 and 1990. Because of this, they suffered from stagnation or even decline. Since 1990, some positive changes can be seen, but only basic services are present. They have not had the opportunity to regain their status as centers, rather functioning as sites of "inner suburbia." Nevertheless, they cannot be labeled neglected centers, because many of them have become popular residential areas, not at all independent of their village-like character.

New Centers Under State Socialism
These centers are Békásmegyer Housing Estate, Káposztásmegyer Housing Estate, and Újpalota Housing Estate. These mass housing estates, developed in the second half of state socialism, were positioned on the peripheries of the city-that is, the agricultural land of the former independent settlements. Mass housing estates were treated like institutional neighborhoods; yet, in reality, only basic services were realized (Losonczy et al., 2020). At the time of their construction, they were elevated to the city-level concept. Soon after their realization, however, they were excluded. Contemporary developments after the regime change concentrated on postponed or, for ideological reasons, neglected functions such as churches, and communitybuilding facilities.

New Centers Under Post-Socialist Capitalism
This typology can be divided into three very different subgroups. ). Except for intermodal hubs, these centers have lost their importance after the realization of the commercial projects.

Conclusions
The research focused on Budapest, a post-communist capital city in Central and Eastern Europe, as a case study to discover how a centrally planned metropolis was handled and modified by decentralized policy. The comparative examination of the development plans from the state-socialist period-1950, 1960, 1970, and 1980-and the post-socialist capitalist era-1994, 2005, and 2013-demonstrated that, from a historical perspective, the hypothesis regarding a cyclical process-from decentralized development to centralized and back to decentralized-is indeed true. In addition, the detailed analysis of the plans (see Section 3) reveals a much more complex and complicated process, during which several paradigm shifts took place. Budapest's urban expansion plan before 1950 was born in the spirit of suburbanization and the pursuit of Central European power, followed by a monocentric capital city plan focused on restoration and austerity after the losses of World War II. Housing policy was a central component of the welfare system of state socialism; however, under the polycentric plans, local center development was neglected, and major transport hubs were highlighted at the level of the capital. By the end of the communist regime, the effects of the economic crisis were already being felt, so a more restrained plan was drawn up. After the system change in 1990, planners took different characteristics and needs into account, which, during the transition period from socialism to capitalism, resulted in continuous conflict among central intentions, local aspirations, and investor interests. In the post-crisis plan of 2013, the initial fight was decided in favor of local communities, but with the need to make everyone feel as though they had benefited. Nevertheless, the plan may be said to correspond to the composite model of urban spatial structures (Bertaud, 2013), according to which, although there are subcenters, the primacy of the city center is unquestionable, and the most important subcenters are positioned on the transition belt, not in the outer area (French & Hamilton, 1979). Each center's development concept was established using a different methodology, so one can only carefully draw models from the shifts in plans. However, from the classification of center development models (see Section 4), it can be stated that most of the industrial towns retained their status and became the sites of metropolization (Bourdeau-Lepage & Huriot, 2002) under state socialism, which made them favorable contemporary development sites. Instead, most traditional villages were neglected because they were not included in city-wide concepts. Some centers were able to regain the character of a center due to successful district-level developments, but these locations basically became local centers after 1990, able to serve the basic needs of the local inhabitants. Both the communist-era and contemporary centers can be seen as experiments that did not become integral parts of the urban fabric.
Therefore, the original hypothesis, based on a cyclical concept, is only valid in the long run. However, if we examine the way in which plans are prepared, it can be stated that-be it a polycentric or monocentric concept-the plans were prepared centrally before 1990, and in a multi-level system featuring the conciliation of interests after the system change. This supports the theory of Gentile et al. (2012) about "homopolitanization" under state socialism, and "heteropolitanization" during post-socialist capitalism, which-layered upon the inherited structure-gives rise to great disparity among the development paths of centers on the outskirts.
To understand the "complex adaptive system" (West, 2017) of Budapest, a further area of research could be to examine the extent to which district development plans correspond to or contradict the current development plan of the capital, and the extent to which the institutional developments actually comply with the (capitaland district-level) plans. An important circumstance for the future is the revision of the urban development plan. In the meantime, the state and the capital aim to extend the concept to the agglomeration-although territorial revision of the capital and separation of some settlements from the capital come up from time to time. Today, we can speak of decentralized development, but the different levels are strongly interconnected. Subcenter developments are influenced not only by local values and interests but are planned by their respective districts (like 23 autonomous cities), coordinated by the Municipality of Budapest, and mainly financed by the state and the EU.
We hope that this study on the evolving system of Budapest's urban centers facilitates an understanding of post-socialist cities. Several cities in Central and Eastern Europe experienced similar ruptures in their political, economic, and social history, which affected their urban planning in the 20th century. Centrally planned periods that were a minimum of 40 (e.g., in Hungary) or more than 70 (e.g., in Russia) years in length resulted in a particular urban structure, partially rehabilitated by contemporary developments. Therefore, in terms of further research, we see a great opportunity to examine the metropolises in regions of similar size and average density, which have also undergone territorial expansion(s) and centrally planned urban developments (especially Prague, Warsaw, Bucharest, and Belgrade). Nowadays, contemporary geopolitical situations and urban policies shape and determine their futures as evolving urban entities.