If you know anything at all about United Parcel Service you know that they put a lot of effort into optimizing their operations. For example, the white roofs on their trucks are actually a translucent material that lets light into the back of the truck so drivers can see the packages and read their labels.
In view of this, I had always assumed that UPS was using some sort of traveling salesman algorithm to plan out their routes. After all, a savings of even 5 miles per route would mean millions of dollars saved over all the routes. It turns out that UPS does exactly that but they didn’t start testing the system until 2008 and have rolled it out to only 50 depots so far. UPS estimates that it will take another half decade before the system is installed throughout the company.
The linked article is pretty interesting if you have even a passing interest in Operations Research or practical applications of the traveling salesman problem. It’s also worth noting the difference between the mathematical solution and the real-world solution as pointed out to one of the UPS staffers working on the problem by a 5 year old.