Transit Vehicle Stopping Regimes and Spacings

Abstract

This study analyzes the optimum number of stops and the optimal vehicle stopping policy for operation of a transit route. Two optimality objectives are considered: minimum user travel time and minimum total cost (user cost plus vehicle operating cost). Three types of vehicle stopping schemes are incorporated in the model: all-stop, on-call stopping and demand stopping. These represent most of the existing fixed route transit stopping schemes. This study further identifies factors which influence the optimum number of stops and the stopping scheme. The sensitivities of the optima to the selected factors (passenger volume, headway, vehicle capacity and access speed) are examined. It is seen that the optimum number of stops is a function of the number of passengers for a one-way vehicle trip; for small passenger volume, the optimum number of stops is large; for large passenger volume, the number of stops decreases and approaches a constant value. Accordingly, the optimal stopping scheme changes from demand, to on-call and finally to all-stop operation. This study provides a theoretical basis for the selection for transit stopping policy and the number of stops under different operating conditions.