How Far Is the Optimal Intercity Distance? Evidence from China

Based on the “centripetal force” and “centrifugal force” of the intermolecular distance model in physics, this article establishes a worthwhile and original mathematical model to analyze the influence of the distribution of cities on urban labor productivity. We incorporate the crowding parameter into the local spillover model and demonstrate the existence of the optimal intercity distance. In addition, we estimate the optimal intercity distance for urban economic efficiency by using data from Chinese prefecture-level cities. Judging from the deviation between the actual average distance and the optimal average distance in each region, the cities in the eastern region are overcrowding, and the cities in the central and western regions are too sparse. Findings in this study carry several important policy implications. For areas in the central and western regions with large administrative areas and large populations, it would be appropriate to increase the number of prefecture-level cities and industrial density through industrial transfer and development. This approach is conducive not only to improving the economic efficiency of the central and western cities and reducing the congestion of eastern cities but also to accommodating the radiation effect of the city on rural areas and achieving the goal of common prosperity.