Each of the journeys that takes place in a particular area may be classified as internal, cross-cordon, or through, according to whether its origin and destination are both inside, one inside and one outside, or both outside the area. The average distances travelled within the area on such journeys may be examined theoretically by findings the average length of a route between two random interior points, a random interior point and a random peripheral point, and two random peripheral points. These three quantities have been obtained or a circular area with twelve different routing systems. Two of the routing systems make use of an internal ring-road concentric with the area considered. The effect of varying the radius of this ring-road on the average length of internal, cross-cordon, and through journeys has been examined, and the positions of the ring-road which minimise these lengths have been found. Three of the routing systems provide a choice between two types of route, and the proportions of the journeys made by each type have been obtained. For the six routing systems provide a choice between two types of route, and the proportions of the journeys made by each type have been obtained. For the six routing systems which make use of ring-roads and radial roads the average distances travelled on roads of each type have been obtained. Some possibilities for further work are discussed.
Samenvatting