Toward a typology of sustainability for cities

Sustainability responses must accelerate to avoid major risks to cities.Climate change impact on cities,likely to be significant if global sustainability initiatives are not quickened,is a paramount example of the risk.World wide meetings of city planning practitioners and researchers agree that an urgent agenda is to work together to empower cities and their governments with funds,tools and mentoring to make the responses needed.In the spirit of this urgent agenda,this paper introduces some practical methods for assessing sustainability associated with transport and urban form in our cities.A concept of strategic scans of future scenarios,which underpins the backcasting approach,has been introduced at the 12 th World Conference on Transport Research(WCTR) in 2010 and has broken urban and transport planning trend.These strategic scans are based on a sustainability framework,the elements of which provide evidence based drivers of sustainability.The framework culminates in metric visualisations for each of the three pillars of sustainability.The paper details some of the operational aspects of these metrics in the form of environmental sustainability-accessibility space,putting into practice measures of environmental stewardship,social equity,economic efficiency,and the relationship among them.The paper concludes with a call of developing a typology of sustainability performance using the strategic scan methodology to extend the principles of the methodology into a useful tool for city governments and contribute to assembling a database of city forms,transport structures,and their sustainability performances.