Scale savings is a main polemical matter in the debate on urban transport utilities. The proliferation of small production units, generally dominating in developing countries, induces split up networks and operation modes. So city managers can look for buses concentration and for firms which manage the service operation aspects in a complete and coordinated manner. But difficulties may arise from their size as far as commercial profitability, externaI savings and service productivity are concerned. From a theoretical point of view, one comes up against the question of scale savings in transport: it is supposed to be nega tive. The analysis of the Brazilian experience leads to other conclusions. About 1.500 urban bus transport firms are mostly private owned and overcome the small scale: it is here proposed their grading in 8 scale types. Hence, structural and operating characteristics of each type are studied. The empirical data result from a research held in cooperation with the scientific and public ou priva te operational representatives of urban transport in Brazil. But the conclusions are not limited ncither to the national Brazilian experience, nor to the context of developing cities. In theory, they throw a doubt about the current presumition of a lack of economies of scales in bus companies.
scale savings; urban transport; bus companies; operational performance