Model for Determining Optimum Bus-Stop Spacingin Urban Areas

Abstract

This paper proposes a model that can be used to determine effectively a sub-optimal policy for bus-stop spacing in urban areas. Transit users are usually interested in minimizing their out-of-vehicle travel time. Conversely, transit operators are interested in minimizing their fixed operating cost. Often, transit operators are required to make transit highly accessible to their patrons, because they operate under stringent budgets. This paper demonstrates, from a sensitivity analysis, that proper spacing of stops can significantly improve the quality of transit service, and decrease travel time, headway, and fleet size (i.e., number of buses). The Highway Capacity Manual, which contains a library of formulas for analyzing various transit performance measures, does not adequately address transit-stop spacing as a primary operational parameter. It is postulated in this report that optimal spacing of bus stops can reduce operating costs by minimizing the required number of buses in service. The proposed model is derived from the fundamental relationships that exist among velocity, uniform acceleration/deceleration, and displacement, and among the average bus operating speed, headway, required fleet size, and potential system capacity. The model can serve as a valuable decision support tool for transit planners in determining suitable spacing of bus stops for prevailing network and traffic conditions.