If you conduct research on networks with a focus on transportation and logistics and teach a variety of related courses on such topics you cannot just sit and stare at a computer terminal (as I am doing now).
You need to be out in the real world to view not only what is happening as a spectator and bystander but also to experience what you research and instruct.
While spending (I just got back the US late on Saturday) another full month in Sweden I never was in a car except for the taxi to and from the airport in Gothenburg (and the rides to and from Amherst to Boston Logan to get to and from Europe).
Imagine -- how many of us in the US can say that we were never in a car for one month!
But the modes of transport that were available to me in Sweden were wonderful:
I could walk and in Gothenburg there are pedestrian walkways, lined with trees and many with bicycle lanes:
I could rent a bike (even the University of Gothenburg makes bikes available, I was told):
I could ride trams and I certainly did and loved the experience and, of course, I flew on planes to get to and from Europe.
I took trains.
in my courses with new students when I return from my sabbatical.