Teoría y práctica del diseño urbano para la reflexión de la ciudad contemporánea

246 Teoría y Práctica del Diseño Urbano structure. The proposition that new urban housing built on brown field sites is consistently better designed is certainly debatable. However, the conceptual framework that Tiesdell and Adams develop, proposing that that the social relations between regulators, designers and developers, and the ‘space’ for design, is delineated by the context of specific develop- ments, is useful. Context is defined in terms of: • site conditions - the complexity of problems to be overcome; • the competitiveness of market conditions -design quality as a competitive strategy, coupled with more discerning, design- aware, urban consumers, and • the scope of regulation -the formal requirements of gaining planning consent, together with the use of tools such as mas- ter plans and design codes The concept of opportunity space is a useful starting point for the development of hypotheses and empirical testing, though the framework could be extended and refined in a number of ways to provide both a fuller understanding of influences on housing design quality and of interactions between contex- tual features. First, the regulatory framework is, as we have discussed, wide-ranging, with complex trade-offs between policy objectives to promote investment and regeneration, achievement of housing targets, negotiation of planning gain and design quality. This points to the significance of power relationships in different economic and market contexts, and of the (softer/ cultural) expectations and aspirations of local planning authorities. In other words, regulation is variably interpreted and implemented. Second, while speculative gains from land ownership may be limited in urban redevelopment contexts, issues of land ow- nership and the values sought by land owners continue to be crucial in determining development densities, the mix and type of housing and the scope for negotiating design qualities. In the aftermath of the credit crunch there were a number of calls for a bigger public sector role in land acquisition and development to reduce risk and ensure higher quality, but the prospects for a radical re-shaping of the residential develop- ment process now seem rather remote. However, the owner- ship of land, the attitudes and expectations of different land