The ferry traffic to Gotland is essential for the island?s ability to live and develop. Yearly, it transports 1,6 million passengers, 500 000 personal vehicles and 750 000 lane meters of freight with four Ro-Pax ferries. The traffic is controlled and subsidized by the Swedish government since 1971 in order to guarantee the inhabitants and industry of Gotland a satisfactory transportation service. As a consequence of the past decades increased traffic quality, mainly due to a decrease in crossing times, the traffic?s environmental impact and costs has also increased.The Master Thesis proposes a new energy efficient traffic arrangement that satisfies the users? preferences in the same extent as today.