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.