Modeling the Joint Distribution of Home and Workplace Locations in a City

Abstract

A number of analyses have been made in recent years to fit models to the separate spatial distributions of homes and workplaces over a city. This paper investigates the fit of a spatial model to the joint distribution of homes and workplaces, taking into account that home and workplace locations are interrelated. The model is expressed as a single continuous function of the home and workplace coordinates, and in its simpler form has three parameters, each with a clear physical interpretation. The model is compared with data on desire-line lengths of work-trips in London and Bristol for different modes of transport, and the results show close agreement in most of the cases that are examined. The analyses suggest that for work trips the model can be used as a suitable, approximation to the trip distribution. The model describes the spatial pattern of travel, and provides a direct estimate of the travel demand, without the need for an iterative procedure. Some implications of the model are discussed and it is shown that the model can be expressed as a continuous variable form of the standard gravity model.