In almost every Latin-American mega-city the environmental situation worsened dramatically and congestion level rose by reason of the increasing use of private cars due to the positive economic development and rising incomes. This development causes in Santiago de Chile on one hand a negative impact on the public transport rate which decreased hardly in the last decade and on the other hand negative effects for the air quality and the urban climate in general. The public transport was in general in a very poor condition and negatively evaluated by the users. Against this background it appears as a big challenge to preserve the current rate of public transport which is in comparison to Europe still high though. To reach this aim the national government of Chile, a highly centralized state, implemented an ambitious reform project called “Transantiago” to modernize the public transport supply in the whole mega-city. The project is based on a city-wide Bus-Rapid- Transit System (BRT) and reorganizes the entrepreneurial structure and the operational as well as the financial system extremely, what means to abandon the old deregulated system and start to integrate public transport modes for improving the quality of urban life. For the first time ever the public transport system of a whole mega-city was changed completely in a very short period at least on the American continents. Therefore the experiences made in Santiago can not only be useful for the improvement of the Chilean case but also for the successful implementation of innovative transport projects in other cities. However, in the implementation process of “Transantiago” difficulties appeared which pointed out to problematic coordination and inappropriate power constellations instead of technical problems. Nowadays after some years of operation it is acknowledged that a too centralized planning and implementation process – i.e. the lack of responsibilities of local actors as well as the neglect of local demand and mobility patterns – was and still is a major source of huge problems “Transantiago” is dealing with. Hence, “Transantiago” opens up a perspective onto specific problems of urban transport policy that can arise due to a lack of decentralization. But to understand what really went wrong in this case study and how to improve the implementation of such policies it is key to study the political context, the interests of the actors, the process of decision-making and implementation – in short: to study governance issues. This study is based on three sources: first several guided expert interviews to get insights into the planning process, second a review of academic articles in order to interpret the current discussion and thinking about (public) transport, and third a review of newspaper articles for understanding the public discussion. The first results show that the still centralistic political system of Chile is one of the mayor obstacle that “Transantiago” is facing: The interests of the main actors, the president of Chile and the national transport ministry, have to be interpreted on the background of the strong neo-liberal focus of the Chilean politics in general and also of the objective be a developed, not anymore developing, country with the positioning of Santiago in a worldwide competition. The research has shown that these findings together with the lack of an authority in charge for metropolitan issues influence the whole planning and implementation process, so that local demand and opinions from citizen were marginal in the end. It is a moot question whether this can lead to a reduced car use and to improve the urban life in Santiago.