Residential zoning is a significant contributor to social segregation within urban areas, operating through a variety of mechanisms. Historically, zoning regulations have explicitly segregated communities based on income, ethnicity, and social class. Single-family zoning, for example, often excludes multi-unit dwellings, effectively restricting access to affordable housing for lower-income groups and perpetuating socioeconomic disparities. This creates areas with homogenous income levels, limiting social interaction and opportunity. Gentrification, often linked to zoning changes, further exacerbates segregation. As areas become more desirable, property values rise, displacing existing residents and replacing them with wealthier individuals. This leads to a loss of community cohesion and a widening gap between affluent and disadvantaged areas. Redlining, a discriminatory practice historically used in the US, denied mortgages to residents of certain neighbourhoods based on race, resulting in segregated housing patterns and limited access to resources. Contemporary zoning policies, while often framed as promoting sustainable development, can inadvertently reinforce segregation if not carefully designed. For instance, prioritizing high-value developments in specific areas can exclude lower-income residents. The spatial arrangement of amenities within zoned areas also contributes to segregation. Areas with better schools, parks, and shops tend to be located in affluent neighbourhoods, further reinforcing social disparities. In conclusion, residential zoning, both historically and currently, plays a crucial role in shaping segregated urban landscapes, limiting social mobility and perpetuating inequalities.

Technological innovation holds significant potential for contributing to sustainable urban development, but it's crucial to acknowledge its limitations. Smart city technologies, such as intelligent traffic management systems, energy-efficient street lighting, and real-time air quality monitoring, can improve urban efficiency and reduce environmental impact. Barcelona is a prominent example, utilizing sensor networks to optimize waste collection and manage traffic flow.

Renewable energy technologies, like solar panels and wind turbines, can reduce reliance on fossil fuels and lower carbon emissions. Cities like Amsterdam are investing heavily in renewable energy infrastructure.

Green building technologies, including sustainable building materials and energy-efficient designs, can minimize the environmental footprint of buildings. Vancouver, Canada, has implemented strict green building standards for new construction.

Innovative waste management technologies, such as waste-to-energy plants and advanced recycling systems, can improve waste diversion rates. San Francisco has pioneered innovative waste management programs, including composting initiatives.

However, relying solely on technology presents drawbacks. Technological solutions can be expensive and may not be accessible to all communities, potentially exacerbating existing inequalities. There are also concerns about data privacy and security associated with smart city technologies. Furthermore, technology alone cannot address the underlying social and political factors that contribute to unsustainable urban development. Effective implementation requires careful planning, community engagement, and robust regulatory frameworks. Technology should be viewed as a tool to support broader sustainable urban development goals, not as a panacea.

Economic factors have significantly driven changes in the location of activities within urban areas between 1950 and 2020. The post-war period saw a decline in traditional manufacturing within city centres, leading to industrial decline and a shift towards suburban and exurban locations. Deindustrialisation, coupled with the rise of service industries, has further accelerated this trend. Service sector jobs, often requiring less space and proximity to traditional industrial infrastructure, have concentrated in central business districts (CBDs) and newer urban extensions. Globalisation has also played a crucial role, with businesses relocating to areas offering lower labour costs or better access to international markets. The growth of finance and technology sectors has further fuelled CBD expansion, often at the expense of traditional retail and office spaces. However, rising property prices in prime locations are pushing some businesses and activities to peripheral areas, creating a more dispersed urban landscape. Transport infrastructure improvements, such as high-speed rail and road networks, have facilitated this dispersal. While some CBD functions remain vital, the overall trend demonstrates a clear shift away from traditional industrial heartlands towards a more complex and dispersed pattern of economic activity.

In conclusion, economic factors have been the dominant force shaping the changing location of activities in urban areas, leading to a significant restructuring of urban space and a shift in the economic hierarchy of cities.