Coordination of local adaptive traffic signal controllers

We consider that freeway traffic flows out onto surface streets and surface street traffic flows into freeways and thus the combined performance of both freeway and surface street portions of a network are interrelated. We analyze a control architecture to improve surface street flow using adaptive signal controllers and introduce an important component towards coordinating control of surface street networks with freeway control. The contribution of this paper relates to the use of a particular adaptive signal control scheme at each intersection called ALLONS-D and a description of how to impart directives from a higher level controller to these local controllers such that traffic performance on the whole is maximized. Our result is a multi-layer approach for controlling the infrastructure in an urban street network. Simulations on an arterial network and a grid network are performed to test the coordination procedure that is presented.