“Bypasses are devices that allow some people to dash from point A to point B very fast while other people dash from point B to point A very fast. People living at point C, being a point directly in between, are often given to wonder what’s so great about point A that so many people from point B are so keen to get there, and what’s so great about point B that so many people from point A are so keen to get there. They often wish that people would just once and for all work out where they wanted to be.”
Douglas Adams, The Hitchhiker’s Guide to the Galaxy
Indeed, as Douglas Adams pointed out, most people do not feel it is particularly useful to just drive around. When they need to be in several different places during the day, they try to plan their route in the most efficient manner, so that their travel time between these places becomes as short as possible. To do so, they look for bypasses, bridges, and any other means of shortening their travel – because unlike birds or airplanes, cars often can’t take the straight-line route between two points.
The previous point is so self-evident that you might wonder why a whole white paper is dedicated to explaining the benefits of knowing the true drive time between two points, given the roads connecting these points, rather than assuming that this drive time is directly related to the straight-line distance. Well, as you read this paper you may find some surprises and not-so-obvious implications of the right and wrong ways of planning your organization’s routes. Also, not everybody uses street-level routing (SLR) in planning schedules and routes for mobile work forces. In fact, some would go out of their way to explain why the intuitively correct way – using SLR – is not the right thing to do. It is interesting to examine the arguments made in defense of such claims.