One reason might be that if you can reduce the effects of traffic you can make our economy more efficient and improve civic life. Also, the theory that is used

One reason might be that if you can reduce the effects of traffic you can make our economy more efficient and improve civic life. Also, the theory that is used to model the behavioral aspects of traffic flow could very well apply to other areas of the social sciences. So a researcher trying to solve a different problems might read this problem and be able to apply the model to his own area of research.