"The hope of the large projects of public-transport-reorganization in Santiago de Chile and Bogotá (Colombia) is, to keep the share of public transport in spite of rising motorization. Hence public and private stakeholders are trying to modernize public transport in Bogotá since the year 2000 with the project ""Transmilenio"" and in Santiago de Chile since 2007 with the project ""Transantiago"". However in both mega cities serious difficulties have been the result during and after the phase of implementation. By means of these problems it is obvious in both examples that projects of this dimension should not only be precisely planned on the technical level but that additionally appropriate governance is a requirement for a successful implementation. In this doctoral thesis the governance of the two projects will be determined to specify an according governance structure, by focussing on the process of decentralization and deregulation in public transport as well as on the integration in general urban developing concepts and on the scale of planning. Aim of this research will be precise recommendations for the governance of the projects ""Transantiago"" and ""Transmilenio"" as well as general recommendations for the implementation of large reorganization-measures in mega cities."