Frightened by the threat of more terrorist attacks and inconvenienced by the heightened security measures put in place to thwart them (see Airport Security), Americans who would have flown to their destinations chose to drive there instead in the wake of 9/11. But in fact they were choosing the more dangerous mode of transit. From October 2001 to May 2003, according to a Cornell study, the uptick in highway travel resulted in close to 2,170 traffic fatalities that wouldn’t have otherwise occurred.