The problem facing rental companies like Avis, Hertz, and National is cross-country travel. Lots of it. Cars rented in
New York end up in Chicago, cars from L.A. come to Philadelphia, and cars from Boston come to Miami. The scene
is repeated in over 100 cities around the U.S. As a result, there are too many cars in some cities and too few in
others. Operations managers have to decide how many of these rentals should be trucked (by costly auto carriers)
from each city with excess capacity to each city that needs more rentals. The process requires quick action for the
most economical routing; so rental car companies turn to transportation modeling