In the developed countries, cars have come into wide use. In the developing countries, with fast growth of economy, cars become popular and the number of them has fast increased because of the population explosion. Therefore especially, it is necessary to examine environmental measures according to a regional characteristic. In order to carry out urban and transportation policies on environment effectively, it is necessary to classify the world countries according to the change of car popularization and to develop the structural model on car-ownership and car-use for each group. Then, in this paper, in order to clarify influence of traffic conditions on the reduction of the CO₂ emissions, which is considered to be the cause of global warming, a structure model is proposed. Although there are some which were analyzed according to the city about each possession factor and the rates of possession, such as an economic standard and a rate of possession, there is no efficient model for such purpose. Moreover, in order to implement urban and traffic policies effectively to global environmental problems, it is necessary for car-ownership and car-use to create the model according to group, after performing the classification corresponding to the situation of the spread of cars, such as a country of saturation, a country where possession is advancing rapidly, and a country where car hasn't spread yet. Then, after classifying according to cluster analysis for the world countries by making into each factor first considered to influence automobile possession, such as economic conditions, urban structure, and traffic environment, about automobile possession of the world countries, the model was built about car-ownership and car-use and its influence factor for every group using the simultaneous equation.