Designing a minimal carbon-footprint city means considering what other improvements outside simply banishing cars to the periphery can be achieved to improve city conditions; implementing passive solar in building design is a major one, as using specific building-design traits can reduce the need for heating and cooling throughout the day, as well as result in a more sustainably-built city. These adaptations include window placement, window sizing on residential buildings, effective placement of air circulation, and specific materials used in construction, while for commercial buildings, the implementation of a green roof can drastically reduce cooling costs (as extremely effective insulation) and also provides more green space for planting gardens (hence increasing the city’s overall albedo, and again reducing the heat island effect.) Green roof design also reduces toxic runoff from storms, and traps water that would otherwise be immediately released back into the atmosphere, keeping the city’s humidity lower.
As an extension of the green roof concept, such design could be applied to car parking; near city-edge transit hubs, large car parks could be installed, designed so that as little exposed surface was bare concrete as possible. The end result would most likely involve partially underground parking, while any aboveground levels would be concealed by the planted outer surface, with the roof being entirely planted-over. All of these design choices are made to increase the city’s overall albedo, allowing it to reflect more heat away from the surface, etc. etc.