Equity in traffic light control

Abstract

A new generation of intelligent Traffic Light Controllers uses Model Predictive Control to minimise delay at signalised intersections. The conventional cycle of set sequences of green phases is dropped for optimisation purposes. This research uses the ethical theories utilitarianism, egalitarianism, sufficientarianism & deontology to define equity. An explicit connection of these ethical theories and technical principles of conventional traffic light controller CCOL & new generation traffic light controller Flowtack, has been provided to identify the change in ethical landscape, from predominantly egalitarian towards relatively utilitarian. Performance indicators for equity in traffic control are defined based on earlier research. Multiple setting changes in Flowtack are proposed and tested in simulation experiments with Aimsun. These experiments show that adjusting Flowtack's objective function can improve the equity scores according to egalitarianism & sufficientarianism, at the cost of the equity score of utilitarianism. The best results are validated using various flow compositions on an alternative intersection. As a result, the gain in equity by the proposed settings becomes greater, as the flow composition becomes more uneven.