Capacity based evacuation with dynamic exit signs

Static evacuation plans for buildings are generally designed to perform optimally when the building is at full capacity. We present a dynamic evacuation guidance system which does this regardless of the number of evacuees, by tailoring a flow-optimal evacuation plan to the current situation. The system assigns routes using a capacity-constrained routing algorithm which anticipates evolutions in path metrics using the concept of “future capacity reservation”. In order to direct evacuees in an intuitive manner whilst implementing the routing algorithm´s scheme, we use dynamic exit signs, i.e. whose pointing direction can be controlled. Yet our routing algorithm performs source-routing on a “per-evacuee” basis and would normally mandate one display per evacuee. We therefore propose a novel algorithm which schedules the dynamic signs according to the algorithm´s output. We validate this concept using simulations, and show how the underpinning assumptions may limit the system´s performance, especially in low-headcount evacuations.