A note on traffic assignment and signal timings in a signal-controlled road network

This paper discusses the problems of using signal timings in a signal-controlled road network to influence equilibrium flows in such a way that some network performance index, e.g. total travel time, is optimised, given that at equilibrium each driver is using a minimum-time route. By means of a simple example, we show that an intuitively acceptable approach explored in other articles does not work and may, in fact, lead to a decline in network performance rather than an improvement.