The Interligado System is a large-scale transit modernization plan for the Municipality of São Paulo, Brazil, which optimizes bus routes and services through the use of advanced technologies for fare integration, bus fleet renovations, new requirements for the companies delivering transit services, and support infrastructure for buses (e.g., priority and exclusive lanes, bus stops, integration terminals, and user information and control systems). The implementation of the Interligado System represents a significant planning and implementation effort involving 39 private bus providers, cooperatives of 6,000 self-employed van operators, and 13,700 vehicles. Electronic farecards allow passengers to ride a combination of lines within a 2-h period. Integration of municipal bus services was completed in May 2004, and integration with Metro and state buses was completed in 2006. The name "Interligado" is no longer used to brand the transit reform, but the project components not only remain in place but have been upgraded over time. The main outcome of the reform has been an increase in public transportation usage within the city of São Paulo. Transit trips grew 15% and boardings grew 49% between 2002 and 2006. The temporal integration scheme has changed the way passengers select a combination of services and has resulted in travel-time and cost savings. Users have responded well to the operational improvements in the priority corridor Passa-Rápido. Nevertheless, the overall rating of municipal buses has declined. The main complaints were high levels of pollution, long waiting and travel times, and congestion. This paper presents a description of the city context and project implementation; an assessment of planning, implementation, and operational issues; and recommendations and lessons learned.