The future sustainability of the urban transport system is largely determined by the technological composition of and measures introduced in the system. This composition is dependent on many background factors. This paper investigates this relationship by means of a panel analysis of experts' opinions on developments of background factors and scores attached to the importance of transport modes in the year 2030; in addition, the model also includes personal features of the respondents. The main findings are that: a reversal of the individualization has a negative impact on several types of modes, which may be explained by a lower mobility level; the main decision level influences the importance of new and collective transport modes and the urban spatial organization has also a clear impact on the importance of collective modes. It is concluded that when governments wish to reduce the external costs of urban transport, developments in society, the spatial organization and the institutional environment - as well as general policies, other than transport oriented but influencing these developments - have to be taken into account by composing urban transport policy packages.