Urban growth is a global phenomenon challenging transportation systems. In developing countries, its effects are amplified by demographic and economic growth pressure. In order to prepare for private car motorization spread and to size transportation projects, it is necessary to re-evaluate the phenomenon in a new worldwide paradigm of digitalization and mobility services. So as to identify emerging motorization patterns and their differences from well-studied metropolitan areas in developed countries, this paper investigates the link between socio-economical characteristics at metropolitan scale and the development of private car motorization. First, the scope of this research is set by a panel of 52 diverse metropolitan areas with a focus on developing countries. Second, a statistical analysis is conducted to investigate the private car motorization phenomenon. Relevant indicators are discussed with concerns about data availability before analyzing those in line with metropolitan level socio-economical characteristics. A focus on car ownership density dynamics with a consumption statistical model on 17 metropolitan areas concludes the analysis. Results confirm that population densities, GMP per capita and income distribution are determinants of metropolitan private car motorization showing faster growth pattern for emerging countries than previously observed in western developed countries.