New Transportation Planning Paradigm: Constraints-Based Planning in Response to Declining Transportation Funds and Growing Interest in Sustainable Communities and Climate Change

Traditionally, cities and counties plan transportation facilities to provide uncongested traffic operations for decades into the future. Under the traditional planning paradigm, transportation projects are selected based on criteria like functional classification, design standards, and ability to provide acceptable operating conditions, as defined by measures such as level of service (LOS)1, through a determined horizon year. Once a design is developed to meet these objectives, funding is obtained and the project is constructed. However, as funding for transportation projects becomes scarcer, more often than not, this traditional planning paradigm is unrealistic. Funding availability to construct a project can no longer be assumed. This has already been well established in regional transportation planning process, but has yet to take hold at the individual city and county level. Moreover, with increasing congestion in urban areas, designing facilities that would meet target LOS thresholds in the long-term is becoming cost prohibitive. Beyond funding shortfalls, the traditional planning paradigm is becoming outmoded for cities and counties as transportation professionals begin to recognize factors aside from automobile operations—including the experience of nonmotorists, preservation of open space, and mos