Municipal emergency services (fire, ambulance, police and others) are indispensable, and at the same time quite expensive elements of the city infrastructure. That is why issues related to justification of the required headcount, technical equipment, deployment locations, appraisal of these services’ capabilities remain extremely relevant. An administration of any city will constantly face these challenges when generating a municipal development plan or when optimizing a municipal budget. Computer simulation systems remain a reliable tool, and, as a matter of fact, the only tool that can be used to assess consequences of reducing or increasing headcount of these services and of changing their parameters. This article contains a short summary of the simulation system called KOSMAS, which was developed by the authors of the article (an international project team) and derived from work experience gained through designing such systems over the last 25 years. This system provoked a great deal of interest among specialists of various emergency services operating in many countries of the world. This system was used to solve tasks of designing and restructuring fire-fighting, ambulance and gas services in Russia, Germany, Turkey and Croatia.