Backcasting for Sustainable Transportation Planning

Transportation problems are often sustainability problems and as such are complex, long-reaching, and difficult to address through incremental policies. Planning for these problems requires analyzing future conditions of the transportation system and the systems with which it interacts. Traditional futures studies using the forecasting method do not deal adequately with the uncertainty inherent in long-term studies of transportation problems. This paper reviews recent innovations in futures studies and their applications to planning studies for transportation system sustainability. The new methods, including scenario planning, backcasting (determining policy to meet future end point), and strategic sustainability assessment, involve both qualitative assessment and scientific models to create and analyze future states. In particular, the paper focuses on backcasting as an alternative to forecasting for scenario building and provides examples of how the method has been applied in the transportation sector. The review suggests that backcasting is a better option for analyzing transportation sustainability problems because it is an action-oriented approach focused on creating desirable future images and developing effective policies for achieving them.