THE LATENT DEMAND METHOD

Travel patterns in a metropolitan area are well described by Newton’s law of universal gravitation as applied to trip interchanges, which is shown in Figure 1. This relationship essentially reflects that the number of trips, regardless of travel mode, between two areas is directly related to the number of trip productions (e.g. population residences) in one area and the number of trip attractions (eg., workplaces, shopping opportunities, schools, etc.) in the other (destination) area. The relationship also shows that impedances (e.g., travel distance and/or time between the areas, conditions of the travel environment, etc.) play a significant role in reducing the amount of trips made between those areas.