Using panel data from 50 countries and 35 urban areas (covering a wide range of country incomes), the authors summarize trends in motorization and the provision of roads, and they examine the ratio of motor vehicles to roads in a production function framework at both national andurban levels....

The authors extend their earlier empirical work by exploring alternative specifications for the relationship between vehicle ownership, road length, and the ratio of vehicles to road length, on the one hand, and income, population, pollution density, and other variables on the other. For the...

The authors survey past trends in vehicle ownership and road network expansion to analyze determinants of their growth at the national and urban level. Surprisingly, they find that: Nationally, income is a major determinant of both vehicle ownership and road length. Nationally, paved road length...