How long does it take to evacuate the building? Are the stairs wide enough to deal with the number of passengers? Where must we situate the ticket machines?
This kind of questions can be answered by modeling and analyzing pedestrian flows with simulation.

Simulation of pedestrian flows in large buildings such as airport terminals, train stations, sports arenas and exhibition halls are not new, but has gained more interest in recent years. The most important reason for this increase is the enormous attention for safety and security in these environments. Another ground why simulation of pedestrian flows rises is the comfort for the pedestrian and the awareness that the shape and layout of large buildings have a big impact on the efficiency of the flow. A third reason is that computers are getting more powerful. This computation power enables modeling of complex environment with many thousands of people on a sufficient detailed level.

PLATO
INCONTROL Simulation Solutions developed the Pedestrian Logistics Analysis Tool (PLATO) to simulate and analyze pedestrian flows, crowding and congestion. PLATO is an entity based pedestrian simulation tool, based on the software Enterprise Dynamics. Each individual pedestrian is modeled as a single entity that flows through a queuing system and has its own characteristics such as origin, destination, preferred walking speed and routing.

The goal of PLATO is to provide information about densities in areas (persons per square meter), flow volumes (persons per width per minute) and transfer times, both in normal operation and during evacuation scenarios. These performance indicators are influenced by the flow of the pedestrians: where do they go, which route do they take and how fast do they walk. Destinations, routing and speeds are influenced by the densities in the building. Pedestrians make routing decisions to avoid crowded areas - if possible - and individual walking speeds are reduced in crowded spaces according to speed-density relations.

PLATO has a two-layer concept for the routing:

• The facilities in the layout (such as desks, ticket machines, shops and exits) are in the Functions layer. In this layer, high level routing, pedestrians decide what will be the next destination.
• The Transfer layer consists of the transfer network, containing elements such as walking areas, stairs, elevators and passages. At this level pedestrians take low level routing decisions: how to go to the next destination.

The resulting densities in the building are directly visible in the model animation: color indicators show the degree of occupation in each area of the building. For analysis PLATO collects data about areas, screenlines and queues during simulation runs. This data is used for
graphical representation and comparison with standards and service levels.

Results of PLATO are used to evaluate existing infrastructures and new designs and to analyze whether investing in new equipment, redesign or rerouting (for example by signposting) is necessary to meet the requirements. PLATO has been applied already with success in:

• Railway Stations
• Airport Terminals
• Exhibition buildings