Large public events such as sporting events, concerts, fairs and street festivals are quite common in metropolitan areas. Because of the high frequency of such events and the increasing number of involved parties, the stakeholders responsible for the organization and execution have to cope with increasing complexity and shortening time frames for planning and preparation. Especially in public transportation, unplanned incidents that occur during these events can have devastating effects because of the high concentration of passengers. Emergency management systems that utilize mobile communication infrastructures can provide prompt information delivery to save human lives. In this contribution we propose a system design for mobile emergency management. We also present an evaluating approach for this system design using a multi-agent based simulation, based on empirical data for a particular large event as well as for normal rush hour traffic. We also consider characteristics of the mobile communication infrastructure.