Leadership in Energy and Environmental Design (LEED) is the most popular and standard metric for quantifying sustainability in the built environment. There are different classes of LEED for many different types of structures, but none of these are broad enough to be applicable to transit projects. Transit agencies striving for sustainability are considering how to attach their sustainability to metric systems like LEED, and many agencies like Denver RTD, New York City’s MTA and Metro King County have tried to scale LEED to fit their projects. By comparing the different methods these organizations have used for evaluating sustainability and the challenges in implementing a system at Seattle’s Sound Transit, it can be concluded that a LEED-style, point-based system or checklist cannot be effective at determining the sustainability of new transit corridors. Instead, a more flexible system that engages greater creativity and acknowledges the real costs of building sustainably is more appropriate.