The paper intends to identify the requirements of technological progress in public transportation and resultant impacts on people’s daily life and social inequalities, with a specific regard to the case of Santiago de Chile. There public transport policy has developed from a de-regulation period in the 1980s to a re-regulation since the 1990s, which seems to have had an important impact on users’ travel habits and competences. During the deregulation period the service was characterized by an uncoordinated, private bus-oversupply, complementary to the efficient public metro. In order to suspend the stigmatization of public transportation as ‘mode of the poor’, the re-regulation period culminated finally in the establishment of the sophisticated ‘Transantiago’ system in February 2007. The Transantiago project envisaged the total modernization of the transport industry by re-organizing the bus network under private operation, renewing the fleet and bus infrastructure, establishing advanced public regulation and monitoring tools, introducing a tariff union with the metro and new electronic tickets. But the design and implementation process of this ambitious project failed, and in its first two years of existence the Transantiago has been rejected by wider parts of the population. The subsequent paper consists in four basic parts. First of all, the theoretical concept of motility is introduced which is assumed to provide an adequate approach for explaining important parts of the Transantiago rejection. Second, the main research interests and the methodological approach are exposed. Subsequently, the case study area of Santiago is presented, giving a short overview on the technical and planning failures of the Transantiago, but concentrating then on the own empiric results (about 40 in-depth interviews with inhabitants and additional expert interviews). Finally, some specific and some general conclusions are drawn, summarizing the social impacts identified and the lessons learned concerning transport modernization in the context of technical progress and related social drawbacks.