a living process, use a collaborative and ethical approach, maintain integrity in leadership and research, and finally foster environmental stewardship. All of these help promote solutions to common environmental issues such as greenhouse gases, urban climate issues, water pollution and waste, energy consumption, and health and wellbeing of site users. The main focus is hydrology, soils, vegetation, materials, and human health and well-being. In SSI, the main goal for hydrology in sites is to protect and restore existing hydrologic functions. To design storm water features to be accessible to site users, and manage and clean water on site. For site design of soil and vegetation many steps can be done during the construction process to help minimize the urban heat island effects, and minimize the building heating requirements by using plants. Regenerative architecture Regenerative architecture includes repurposing abandoned spaces to increase green space by using cost-effective design techniques. An old railway line in Bangkok has been recently converted in the Phra Pok Klao Sky Park, a green park in the congested city of Bangkok. The New York High Line project is one of the oldest examples of regenerative architecture where an abandoned railway line is repurposed into an elevated park and social gathering space for its citizens. Transportation As major focus of the sustainable cities, sustainable transportation attempts to reduce a city's reliance and use of greenhouse emitting gases by utilizing eco-friendly urban planning, low environmental impact vehicles, and residential proximity to create an urban center that has greater environmental responsibility and social equity. Poor transportation systems lead to traffic jams and high levels of pollution. Due to the significant impact that transportation services have on a city's energy consumption, the last decade has seen an increasing emphasis on sustainable transportation by developmental experts. Currently, transportation systems account for nearly a quarter of the world's energy consumption and carbon dioxide emission. In order to reduce the environmental impact caused by transportation in metropolitan areas, sustainable transportation has three widely agreed-upon pillars that it utilizes to create more healthy and productive urban centers. The Carbon Trust states that there are three main ways cities can innovate to make transport more sustainable without increasing journey times – better land use planning, modal shift to encourage people to choose more efficient forms of transport, and making existing transport modes more efficient. Car free city The concept of car free cities or a city