Car-based transportation networks (as in Phoenix) necessitate parking at origin and destination in order to establish a link—but the space devoted to parking lowers its ability to provide housing and consumer amenities. Walking and transit networks (as in Manhattan) have no such tradeoff, and a city reliant on them will be able to make fuller use of its land for productive purposes like amenities and housing. However, they hinder mobility in other ways: walking does not get you far, and using transit requires adhering to the routes and stops the city's transit agency provides. In this paper, we develop and calibrate a spatial consumer city model to study what would happen if Phoenix banned cars, delineating the roles of parking conversion, of the light rail network, and of a last mile option. Together with a last mile option, Phoenix's current light rail line would be able to sustain a meaningful (if smaller) population—but only if Phoenix converts its current parking to other uses. We then ask the reverse: what would happen if Manhattan required parking? The model indicates the island would essentially empty, as the declining capacity of each block lowers the vibrancy of the city, inducing still more residents to leave. Altogether, these model outcomes tell a story of agglomeration through complementarities. The transportation network and incumbent land use must ensure a high degree of access to jobs and amenities in order for enough people to choose to live in the city and thereby support those amenities.

基于汽车的交通网络（例如在凤凰城）需要在始发地和目的地停车以建立联系，但是，专用于停车的空间降低了其提供住房和消费者便利设施的能力。步行和公交网络（例如在曼哈顿）没有这种折衷，依靠它们的城市将能够更充分地利用其土地用于生产性目的（如便利设施和住房）。但是，它们以其他方式阻碍了人们的出行：步行不会使您走得太远，使用公交需要遵守路线，并停止城市公交代理机构提供的服务。在本文中，我们开发并校准了空间消费城市模型，以研究如果凤凰城禁止使用汽车会发生什么情况，描述了停车转换，轻轨网络和最后一英里选项的作用。加上最后一英里的选择权，凤凰城当前的轻轨线将能够维持有意义的人口（如果人数较少），但前提是凤凰城将其当前的停车位转换为其他用途。然后我们提出相反的要求：如果曼哈顿需要停车，将会发生什么？该模型表明，由于每个街区的容量下降，城市的活力降低，导致更多居民离开，该岛实际上将是空的。总之，这些模型结果通过互补性讲述了一个集聚的故事。交通网络和现有的土地使用必须确保高度获得工作和设施，以便有足够的人选择住在城市，从而支持这些设施。