Specific in-depth studies have been carried out into the regulatory development of national and international maritime traffic and the development of the trans-European transport networks and motorways of the sea. The research carried out focused in particular on the legal framework for maritime cabotage services, which have been affected by a major liberalisation process. The research also examined Community legislation on the emergence and development of trans-European transport networks in the context of liberalised maritime traffic. Particular attention has been paid to the study of the Motorways of the Sea and incentive programmes recently adopted in the European and national context.