Portland, the largest city in Oregon with over 600,000 inhabitants has become a global model of transit-oriented development (TOD). Peter Calthorpe, a founding member of the Congress for New Urbanism was one of the original pioneers of TOD. Calthorpe explains that the model follows a simple formula: diversity: diversity of population and diversity in land use. Therefore the occupants of loft apartments and townhouses are not confined to one exclusive population group. The model strives for a 'complete neighbourhood' with a broad range of ages and incomes. This neighbourhood is complimented by the provision of local stores, parks, schools and civic spaces.

Calthorpe is also keen to stress that diversity in land use does actually exist in many areas. However it's potential is often hampered by arterial roads, making these spaces both impractical and dangerous for pedestrians. A key element of TOD is the human scale – creating streets that are not only auto-friendly but also amenable to cycling and walking. Portland's citizens have adapted to the changes with most favouring open-air pedestrian shopping streets over the shopping mall experience. Calthorpe also predicts increased density as a practical benefit for an ageing population that benefit from having more resources nearby. As public spaces improve and follow the TOD model we are likely to see a shift from secluded suburbia towards urban living.