The relationship between population density,automobile ownership and automobile use: Its role in transportation planning

This study investigates the effect of population concentration, a regional issue, on automobile ownership and use. The approach is simple, straightforward and based on two empirical relationships: The first is an empirically determined function based on the hypothesis that lower population densities and higher incomes cause higher levels of automobile ownership. The second relationship expresses gasoline used per auto per year as a function of the density of population.Two important conclusions result. First, the long range policy goal of reducing automobile congestion in a region might be met by proper land use planning to change population distribution which in turn effects the total number of automobiles and automobile congestion in the region. Second, a policy option that tends to reduce the number of automobiles in a region may not reduce air pollution and gasoline consumption. The methodology developed in this paper also permits the measurement of the tradeoff between automobile congestion and gasoline consumption.The author is indebted to Professor Edward Ames for his encouragement and helpful comments. Thanks are also due to Dr. Robert Klepper for many useful comments on an earlier draft.