A finalist in the WPA 2.0 competition sponsored by UCLA Citylab, Nicholas de Monchaux and collaborators have provided a case study showing the impacts of the "spaces between places," spaces owned by the city but unused and still maintained. Monchaux's group, using geospatial analysis identify thousands of these publicly owned, abandoned spaces and quantify their transition into a network of urban greens.
Using San Francisco as a case study, the abandon spaces found happen to exist in areas heavenly burdened with energy efficiency and drainage issues, combining to make up an area that rivals Golden Gate Park. Local Codes/Real Estates, as the project is called, clearly displays the cost savings associated with eliminating needless infrastructural remediation while providing a healthy network of urban ecology.
Given the savings involved, this would seem quite actionable and applicable to any major city. With the intention of the individual spaces being designed by "hyperlocality," communities will be able to develop and fund their spaces to address specific needs.