The Economics of Radiator Springs: Dynamics, Sunk Costs, and Spatial Demand Shifts
研究了州际公路开通如何影响当地汽油零售市场的调整，发现新公路靠近旧路线时厂商平均规模提前一年扩大，而大幅改变交通流时厂商数量在开通后才增加，揭示了竞争过程中进入的作用取决于产品空间是否更拥挤。
Harold Demsetz famously emphasized that the relationship between industry structure and competition runs in both directions. Competition thus can lead industries to adjust to demand increases through larger firms rather than more firms. We investigate this insight empirically by examining how local gasoline retail markets adjusted to interstate highway openings. We find that when a new highway was close to a previous route, average producer size increased beginning 1 year before it opened. If instead the interstate substantially displaced traffic, the number of producers increased beginning only after it opened. These results empirically illustrate how the role of entry in the competitive process depends on whether entry makes product space more crowded.