On optimizing bus dwell times to reduce the probability of stopping for a red light at intersections

This paper provides an analytical approach for the problem of reducing the time spent by buses at signalized intersections, waiting for green phase, by suitably increasing the dwell time at bus stops. It is well known that the main motivation to tackle with this problem lies on the expected advantages in terms of reduction in the number of stops, in the fuel consumption, in an increase of the comfort and in the number of passengers able to board the bus. In this framework, the availability of an analytical model makes the search of a solution and the analysis of the relevant properties direct and faster with respect to simulation approaches. The problem is modeled as a non-linear stochastic optimization problem aimed at determining the best departure time from the bus stop in order to make the bus arrive at the signalized intersection during the green phase. The uncertainties related to travel time and passengers' boarding are specifically modeled and their influence on the solutions is discussed. A detailed discussion of the resulting performances is provided via a simulated case study.