In an earlier paper, a theoretical model of commuter traffic in the central areas of towns was developed by the author and used to calculate the area required for roads in idealized towns. This paper extends the model and avoids an earlier approximation. As before, data on the capacity of roads, the density of workplaces, and the fraction of the ground area devoted to roads in actual towns are used. It is assumed that the central area of the town is circular, that people live outside this area, but work inside it, and that workplaces are distributed uniformly in those parts of the central area not devoted to roads. Three different routing systems for the journey to work within the central area are considered and described. Two alternative assumptions are made about radial roads. Calculations are made of the distance traveled/unit area at different distances from the center, of the average distance traveled, and of the radius of the central area when provision is made for all traffic demands. The maximum number of people who can travel to work within the central area when a fixed proportion of it is devoted to roads is calculated. It is shown that in most practical cases the prior approximation produced a relatively small error. The relation between average journey time within the central area and the number of commuters in a given town is calculated for the case of radial-arc routing.
Abstract