This report identifies the characteristics of the metropolitan transport authorities (MTAs) in the Barcelona, London and Paris areas that make them effective, and makes recommendations for the establishment of a new MTA in Korea’s capital region. It reviews governance arrangements and responsibilities for strategic planning, investment, data management, public transport services and the management of multi-modal transfer centres. Successfully managing mobility services in metropolitan areas is central to improving accessibility and to the well-being of their populations. The challenges faced include coordinating multiple government and non-government stakeholders, finding an institutional structure that meets the needs of both the urban-core and the larger commuting area, and striking a good balance between the powers of central government and local authorities. These challenges are particularly present in countries in the process of decentralisation. Successful MTAs give local authorities a prominent role in decision-making while maintaining a coherent larger scale vision in planning, policy-making and investment. Strong financial and technical capacity have proved critical.