An exploration of options for strengthening the physical infrastructure for a new Palestinian state, this study builds on analyses that RAND conducted between 2002 and 2004 to identify the requirements for a successful Palestinian state. That work, Building a Successful Palestinian State, surveyed a broad array of political, economic, social, resource, and environmental challenges that a new Palestinian state would face. This study, The Arc: A Formal Structure for a Palestinian State, examined a range of approaches to siting and constructing the backbone of infrastructure that all states need, in the context of a large and rapidly growing Palestinian population. The research team develop a detailed vision for a modern, high-speed transportation infrastructure, referred to as the Arc. This transportation backbone accommodates substantial population growth in Palestine by linking current urban centers to new neighborhoods via new linear transportation arteries that support both commercial and residential development. The Arc avoids the environmental costs and economic inefficiencies of unplanned, unregulated urban development that might otherwise accompany Palestine's rapid population growth. Constructing the key elements of the Arc will require very substantial investment of economic resources. It will also employ substantial numbers of Palestinian construction workers. It seems plausible that key aspects of the Arc design can be pursued, with great benefit, even before an independent Palestinian state is established.