Transit textbooks and engineering manuals indicate that the capacity of Bus Rapid Transit –BRT – systems does not exceed 20,000 passengers per hour per direction. The implementation of the TransMilenio BRT System, in Bogotá, Colombia, showed that the systematic combination of multiple platforms at stations, overtaking lanes, level boarding, prepayment, large buses with multiple doors, express and local services, and traffic engineering measures at intersections, allow for very large passenger throughput. Measurements indicate actual throughput of 43,000 passengers per hour per direction with an average bus occupancy of 150 passengers per articulated bus, and a commercial speed of 22-24 km/hour. According to special formulae developed for the analysis of high capacity BRT corridors, the critical section of TransMilenio has a practical capacity of 48,000 passengers per hour per direction with its existing infrastructure and 150 passengers per bus – 35,000 passengers per hour per direction with 110 passengers per bus. Changes in existing infrastructure, such as additional platforms, higher capacity vehicles, non-grade facilities at critical intersections, among other improvements, may increase the capacity, speed, reliability and quality of service of the system.