Writing in Nautilus, Tom Vanderbilt discusses how the human element complicates the already complex traveling salesman problem.
Vanderbilt tells how a UPS project manager, explaining his job to his daughter's class, had to be reminded by a fifth grader of constraints posed by real-world realities like melting ice cream. He recaps the P versus NP problem perplexing computer scientists and describes how modern routing models try to take into account changes in a truck driver's home life.
Figuring out the human side of transport optimization, Vanderbilt concludes, is an on-going process, one that requires quantitatively-minded operations researchers to wrap their minds around people. He quotes UPS project manager Bob Santilli:
One of the hardest things to teach a math analytics group is the difference between a feasible solution and an implementable solution. Feasible just means it meets all the math constraints. But implementable is something the human can carry out.
Read the essay.