Years of experience have provided substantial evidence of persistent planning problems that are common to many proposals for major transit investments. These problems frequently are rooted in the system-level planning performed at the scale of the metropolitan area or region. This area is the scale at which different transportation services and modes form an interrelated system for moving people and goods between origins and destinations where the household, employment, and commerce activities occur. System planning provides the big-picture context for foundational planning elements, such as developing a coherent vision for the region's future and translating that vision into concrete goals and objectives, which provide the basis for identifying transportation needs and problems. The usage of potential new transportation infrastructure and major services should be forecasted at the regional level to capture essential travel behavior characteristics. Five system planning activities are particularly necessary to provide the necessary groundwork underpinning successful projects: regional needs identification and prioritization, land use planning coordinated at the level of the metropolitan area, technical analysis and forecasting, early consideration of environmental issues, and financial planning and fiscal constraint. The components of these activities that are most critical to developing successful large-scale transportation projects are discussed, along with associated strategies for improving the linkage between system-level planning and the development of individual projects.