Traffic regulation in large conventional urban centres is a trouble for most policy makers, due to the huge conflicting needs and the relevant economical interest related to any alternative. Around Venice lagoon and Venice town centre the totality of goods and most of passenger traffic is conveyed by water, the only crowded urban area in the world relying thoroughly on this way of transportation. Walking is more and more disregarded as an alternative, and innovative, ground oriented public transportation technologies cannot be easily adopted in this singular scenario. The frail architecture of the urban town and the lagoon morphology suffer chiefly because of wave-making and energetic dispersion due to water transportation, which increased dramatically since last forty years. Total amount of lagoon operating boats is more than 35.000 by now, to be compared with 70-000 residents and more than 50.000 tourists per average day. Air and acoustical pollution, together with mooring spaces scarcity assessment, specifically considering naval architecture aspects of powering and environmental impact of urban navigation. This paper deals with main findings and methods adopted for problem definition, eventually detailed into the new 2003 navigation rules within Venice lagoon issued by VPA.
