This article describes a model (known as COPS, COuntywide Police Simulation System) which simulates the receipt of police, fire, and emergency medical calls at a public safety communications center, with subse quent dispatch of law enforcement officers to police events. The delivery of police services involves the processing of an event, or call-for-service, from the moment that the call is received at an emergency communications center through disposition of the call by police officers. This process involves telecom municators, dispatchers, and police officers. From the telecommunicator perspective, it includes the receipt of a request for police service at a public safety communications center, the assignment of the call to an available telecommunicator, the interview of the calling party by the telecommunicator, and the transfer of the event in formation to a police dispatcher. The dispatcher is then responsible for selecting the most appropriate police unit(s) for dispatch. The police officer must travel to the scene, service the complainant, clear from the call, and return to preventive patrol. The model examines the interaction of external variables, including the type of call, the frequency of calls, the number of telecommunicators on duty, the number of police cars in service, the deployment pattern of the officers, the number of cars to be dispatched, and the dispatch plan. By modifying the values that these variables can hold, the distribution of workload among police officers can be observed, response times and service times can be examined, and dispatching policies can be evaluated. Sensitivity analysis can be performed without disrupting the life-critical nature of the live operation.