AN AVM SYSTEM PROVIDES REAL-TIME LOCATION AND STATUS INFORMATION FOR EACH POLICE VEHICLE IN THE SYSTEM AND TYPICALLY INCLUDES A DISPLAY SHOWING A MAP OF THE CITY WITH CARS POSITIONED AND IDENTIFIED BY THEIR IDENTIFICATION NUMBERS. THE PRINCIPAL GOAL OF THE ST. LOUIS PROJECT WAS REDUCTION IN RESPONSE TIME, WHICH, IT WAS BELIEVED, WOULD INCREASE THE RATE OF CRIMINAL APPREHENSION AND POSSIBLY DETER CRIME. OTHER OBJECTIVES INCLUDED IMPROVED OFFICER SAFETY, MORE EFFECTIVE COMMAND AND CONTROL, LESS VOICE BAND CONGESTION, AND BETTER SUPERVISION OF THE POLICE FIELD FORCES. THE EVALUATION INVOLVED THREE SEPARATE ANALYSES--TECHNOLOGICAL, OPERATIONAL, AND ATTITUDINAL--AS WELL AS A COST-EFFECTIVENESS STUDY. THE EVALUATION RESULTS WERE UNFAVORABLE FOR RESPONSE TIME REDUCTION, FAVORABLE FOR IMPROVED OPERATIONS DUE TO DIGITAL COMMUNICATIONS, AND MIXED IN THE REALIZATION OF OTHER OBJECTIVES. POOR SYSTEM PERFORMANCE HAD SOME INFLUENCE ON THE EVALUATION RESULTS. DURING THE EVALUATION PROCESS IT BECAME CLEAR THAT FULL SYSTEM POTENTIAL COULD NOT BE ASSESSED WITHOUT SOME CHANGE IN POLICE PROCEDURES AND OPERATING METHODS. SUCH POTENTIAL RELATES TO THE USE OF DIRECTED DISPATCH RATHER THAN ALL POINTS BROADCAST FOR EXTRAORDINARY EVENTS SUCH AS PURSUITS, BURGLARIES, AND DISTURBANCES; THE DYNAMIC REALLOCATION OF THE FORCE TO MAINTAIN A PATROL PRESENCE OR TO REDUCE QUEUING LEVELS IN AREAS WHERE EXCESSIVE CALLS FOR SERVICE HAVE DEPLETED FORCE AVAILABILITY; AND BETTER SUPERVISION FOR THE FORCE MADE POSSIBLE BY THE NEW INFORMATION THAT THE AVM SYSTEM SUPPLIES. AVM ALSO SERVES AS A HIDDEN SUPERVISOR PRODUCING BETTER OFFICER BEHAVIOR. IMPROVED EFFECTIVENESS OF THE FORCE, GREATER PRODUCTIVITY, AND A COST-EFFECTIVE SYSTEM CAN ALSO RESULT. MATERIAL ON ALTERNATIVE TECHNOLOGIES IS APPENDED. GRAPHIC AND TABULAR DATA ARE PROVIDED. SEE ALSO NCJ-51077. (AUTHOR ABSTRACT MODIFIED)