ABSTRACT
In urban environments, transport is vital for social and economic life and may be provided by several means. The specific modes used in a city are highly correlated to its size, to the quality and cost of available modes and to the economic and social characteristics of its inhabitants. As a general rule, in smaller cities walking and cycling are the dominant modes, while in larger cities, motorized means become essential, be they public (bus, train, metro) or private (automobiles and motorcycles). As transport implies the consumption of natural resources and the generation of some negative impacts such as accidents, pollution and congestion, the use of any particular mode and the overall balance of modes in a particular city have to be analyzed carefully.
