If we compared the economic system with a human being we could say transports are its throbbing blood. Without these services the economic development of the century that just ended would not have been possible. Transport plays an important social role also in meeting the travel and communication needs for most people. The transportation represents also a basic tourism service, without which the journey cannot be made.The services we look at have also a negative side, as they are activities causing significant harm to the environment. One example is tourist transportation, mostly road and air transportation, with a negative impact due both to emissions and to the high level of sound pollution. Thus, in 2005, of the 5839.4 thousand arrivals (foreign travelers coming to Romania), 75.9% have used road transportation and 15.7% air transportation (5.2% – rail transport and 3.2 % – water transport) As for the Romanian citizens’ travels abroad, of the 7139.8 departures in 2005, 84.1% used road transportation, 12.3% air transportation, and only 3.1% rail and 0.5% water. In 2006 the number of foreign travelers coming to Romania was 6037 thousand arrivals, and the departures for the Romanian citizens were 8906. Sustainable development is a concept that can be implemented only by striking a balance between economic and social development and environment protection. Therefore, transportation – of both goods and people – should reach this balance, which can be achieved only through a thorough knowledge of the system, paving the way to identifying viable solutions for mitigating the pollution caused by transport without hurting economic development.