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This paper gives a model in which two urban emergency service units (such as fire engines or ambulances) cooperate in responding to alarms or calls from the public in a specified region of a city. Given the home locations of the units and the spatial distribution of alarm rates, it is possible to specify which unit should respond to each alarm by defining a response area for each unit. The average response time to alarms and the workload of each unit are calculated as functions of the boundary that separates their response areas. The boundaries that minimize average response time and the ones that equalize workload are determined. Some boundaries can be dominated, in the sense that another boundary improves both workload balance and response time. The set of undominated boundaries is found.

Analysis of self-report and official record data obtained from nearly 2200 male prison and jail inmates in California, Michigan, and Texas shows that offenders can be usefully classified according to the combinations of crimes they commit. The most serious inmates, those who concurrently commit robbery, assault, and drug dealing, disproportiontely commit these defining crimes at high rates. They often commit burglaries, thefts, and other crimes at high rates too—frequently at higher rates than other types of criminals, including those who specialize in those crimes. Unfortunately, information currently available from such sources as official arrest and conviction records do not permit criminal justice officials to distinguish meaningfully between these high-rate, serious offenders and other types. Low-rate offenders can be more accurately identified using potentially available information on key characteristics: multiple drug use, unstable employment, juvenile use of hard drugs, and violence before the age of 16.

An urban emergency service system provides mobile units (vehicles) to respond to requests for service which can occur at any time and any place throughout a city. This paper describes the common characteristics and operational problems of these systems and surveys the various methods, both traditional and recently developed, which may be used for allocating their units. Aspects of allocation policy discussed include (1) determining the number of units to have on duty, (2) locating the units, (3) designing their response areas or patrol areas, (4) relocating units, and (5) planning preventive-patrol patterns for police cars. Typical policy changes which may be suggested by the use of quantitative allocation models include selective queuing of low priority calls, varying the number of units on duty (and their locations) by time of day, dispatching units other than the closest ones to certain incidents, relocating units as unavailabilities begin to develop, and assigning police cars to overlapping patrol sectors. As a result of making such changes, it is often possible to reduce queuing and travel time delays, improve the balance of workload among units, and enhance the amount of preventive patrol where needed.