3.27 Circular city, revisited Suppose that two points (R1, 2) and (R2, 2) are independently, uniformly distributed over a circular city of radius ro and area A= Suppose further that this city has a large number of radial routes and circular ring routes so that the travel distance between (R1, 1) and (R2, 2) can be accurately approximated as
D = |R1 - R2| + Min [ R1, R2] |1 - 2|
where 0 |1 - 2| signifies the magnitude of the angular difference between 1 and 2. In words, travel from an outer point, say, (R1,1) if R, > R2, to an inner point (R2,1) first occurs along a radial route to a ring located a distance R2 from the city center, and then along that ring (in the direction of minimum travel distance) to (R2,1); the same path is traveled in reverse if travel is from (R2,1) to (R1,1). A sample path is shown in Figure P3.27.