Cities and Warfare: The Impact of Terrorism on Urban Form

What impact will terrorism have on America’s cities? Historically, large-scale violence has impacted cities in three ways. First, concentrations of people have an advantage in defending themselves from attackers, making cities more appealing in times of violence. Second, cities often make attractive targets for violence, which creates an incentive for people to disperse. Finally, since warfare and terrorism often specifically target means of transportation, violence can increase the effective cost of transportation, which will usually increase the demand for density. Evidence on war and cities in the 20 th century suggests that the effect of wars on urban form can be large (for example, Berlin in World War II), but more commonly neither terrorism nor wars have significantly altered urban form. As such, across America the effect of terrorism on cities is likely to be small. The only exception to this is downtown New York which, absent large-scale subsidies, will probably not be fully rebuilt. Furthermore, such subsidies make little sense to us.