In SuperFreakonomics, we catalogued some of the collateral costs of the 9/11 terrorist attacks, including roughly 1,000 extra traffic deaths in the U.S. in the three months after 9/11, the result of so many people driving instead of flying:
Such trickle-down effects are nearly endless. Thousands of foreign-born university students and professors were kept out of the United States because of new visa restrictions after the September 11 attacks. At least 140 U.S. corporations exploited the ensuing stock market decline by illegally backdating stock options. In New York City, so many police resources were shifted to terrorism that other areas — the Cold Case Squad, for one, as well as anti-Mafia units — were neglected. A similar pattern was repeated on the national level. Money and manpower that otherwise would have been spent chasing financial scoundrels were instead diverted to chasing terrorists— perhaps contributing to, or at least exacerbating, the recent financial meltdown.
The Wall Street Journal now reports on a most unlikely unintended consequence of the attacks and the ensuing hunt for Osama bin Laden: