Minimisation of total delay in two-way coordinated arterials

Coordination of the signalised intersections of an arterial is a widely studied problem, with the aim being to find optimal offsets, when the other control parameters (cycle time, effective greens, etc.) are designed. Optimal offsets are generally those that are able to minimise the stops at intersections for vehicles travelling along the coordinated arterial or to maximise bandwidth. While the problem is very simple for one-way arterials, it is more complex for two-way arterials where the problem is usually approached as one of bandwidth maximisation. However, the latter does not ensure minimum total delay (or total travel time) on the network. In this paper we study the problem of coordinating two-way signalised arterials with a view to minimising total delay, using a microsimulation approach to explore the solution set. Initial results show that the objective function of the problem is not convex and that several local optima can be identified.