The author provides new insights into the relationship between transport and the environment, the role of technology and the meaning of the concept of sustainable development for the transport sector. Special attention is given to¤ the relationship between technological progress and policy. The different theoretical approaches are combined to create a strategy for R&D and the implementation of mega- technological innovations. The empirical part deals with tw¤o specific cases: Maglev technology and fuel-cell technology for transport purposes. Taking into account the new theoretical insights and the empirical findings, the author presents a synthesis and draws conclusions which are impo¤ rtant for researchers and professionals in transportation, environmental sciences and related fields. Keywords: sustainability, environmental sciences, traffic, Maglev - technology, fuel cell technology Contents: Objectives and methodological approach of the study.- Theoretical Part.- Transport, technology and sustainable development.- The evolutionary theory of technology dynamics.- Policy making in networks and alliances: impli¤cations for a sustainable technology policy.- Directing innovations in the transport sector: a synthesis.- Empirical Part.- Exploring trends and ' weak signals'.- The Maglev-technology.- The fuel-cell technology.- Some conclusions and reflections.