The image of a backed-up highway leading away from the scene of a natural disaster may soon be history, if researcher Yi-Chang Chiu and his colleagues at the University of Arizona have their way. They've developed a traffic simulator that uses real-time traffic data along with detailed state and federal traffic statistics and behavior modeling to allow officials to simulate disaster evacuations in real time -- or even predict the course of events as a disaster is happening. The software adjusts for such varied data as driver reactions to radio reports and wind dispersal of smoke and other pollutants; it even calculates the number of casualties and their effect. Chiu has been building the simulator since 1995, and he's ready to start selling to state transportation and medical emergency agencies. Interestingly, Chiu says his real research focus is on calculating optimum "value-priced" toll rates -- something we're certain most state transportation departments regard as the real disaster.