The New Urban Agenda (NUA) sets a new vision of sustainable urban development to help cities deal with the challenges of changing demography. While numerous articles have addressed how the NUA can be implemented at different levels and in different areas, this article points out the potential limitations in incorporating the NUA into metropolitan transport policies. The relevance of the limitations can be seen in three main fields: incompatibility between legal and financial frameworks and the functional and spatial structures of metropolitan areas, the characteristics of how transport systems are developed as part of metropolitan functional and spatial structures and the inconsistency and inadequacy between political declarations (NUA) which are based on ideas and programmes and the objectives of strategy papers which are based on diagnoses, data analyses and predictive models. The authors put forward the thesis that by concentrating on cities, the NUA leaves out some of the characteristics of metropolitan areas. As a consequence, although the NUA can work successfully for metropolitan cores, outer areas are not covered directly. In order to verify the thesis, a comparison was made between the NUA's transport system approach with experience from running and planning metropolitan transport systems described in the literature. The results of the comparative analysis, confirmed the thesis of the authors and made it possible to formulate general conclusions regarding the specific conditions of metropolitan areas for the running and developing of the transport system. By using explanatory case study of Tri-City Metropolitan Area (TMA) and the Strategy for Transport and Mobility for TMA 2030 general assumptions were confirmed and explain in more details. The NUA and STM were compared for how they address the main areas of intervention related to transport. Differences were identified and recommendations were formulated, should the documents be updated. The STM must be updated in areas such as equity and climate change mitigations while the NUA should be expanded to cover the specific conditions that prevail in functional and metropolitan areas.