THE HYPERCUBE MODEL WAS ORIGINALLY DEVELOPED TO AID POLICE PATROL DISPATCH. ITS TWO COMPONENTS ARE A DESCRIPTIVE MODEL, WHICH DETAILS THE OPERATING CHARACTERISTICS OF A SYSTEM WITH LIMITED RESOURCES, AND A LOCATION MODEL, WHICH DETERMINES VEHICLE PLACEMENT TO MINIMIZE AVERAGE RESPONSE TIME. THE APPLICATION OF THE DESCRIPTIVE MODEL TO A SAMPLE CITY SHOWS HOW THE MODEL CAN BE USED TO DETERMINE THE NUMBER OF CALLS GENERATED IN EACH AREA OF THE CITY, TRAVEL TIMES, LOCAL TRAFFIC CHARACTERISTICS AFFECTING TRAVEL TIME, AND AVERAGE SERVICE TIMES FOR EACH TYPE OF CALL (EMERGENCY MEASURES AT THE SCENE, TRAVEL TO HOSPITAL, TRANSFER TIME AT HOSPITAL). SAMPLE DATA ARE TABULATED. THE LOCATION MODEL IS THEN USED TO DETERMINE OPTIMUM PLACEMENT OF AMBULANCES. BOTH MODELS ARE THEN USED TO ASSESS THE VALUE OF A MOBILE CORONARY CARE UNIT. CLINICAL DATA IS USED TO CALCULATE THE RISK OF DEATH FROM VENTRICULAR FIBRILLATION BEFORE REACHING A HOSPITAL. IT IS FOUND THAT SUBSTITUTING A MOBILE CORONARY CARE UNIT FOR ONE OF THE SYSTEM AMBULANCES SIGNIFICANTLY INCREASES RESPONSE TIME FOR THE REMAINING AMBULANCES, BUT SIGNIFICANTLY DECREASES TIME AT RISK FOR THE HEART ATTACK VICTIM. THE PLANNING ISSUES TO BE CONSIDERED IN CHOOSING AN EMERGENCY SERVICE SYSTEM ARE DISCUSSED. IT IS NOTED THAT THE DATA PRESENTED WERE COMPUTER-GENERATED AT A COST OF ABOUT $20. THE MAJOR EXPENSE IN USING SUCH MODELS IS THE COST OF OBTAINING LOCAL INFORMATION. NOTES AND REFERENCES ARE APPENDED. (GLR)