EACH CASE HISTORY PRESENTS AN OVERVIEW OF SYSTEM OPERATION, COSTS TO SET UP THE SYSTEM, COSTS TO MAINTAIN IT, AND A DISCUSSION OF ITS USEFULNESS. THE FIRST EXAMPLE IS A TRAFFIC CITATION SYSTEM IN TULSA, OKLAHOMA. THE SECOND AND THIRD ARE POLICE PATROL AND INQUIRY SYSTEMS IN KANSAS CITY, MISSOURI, AND LOS ANGELES. THE FOURTH IS THE SANTA CLARA, CALIFORNIA CRIMINAL JUSTICE INFORMATION SYSTEM. THE TRAFFIC CITATION SYSTEM SO IMPROVED THE COLLECTION OF FINES THAT ITS $64,000 INITIAL COST WAS OFFSET BY AN INCREASE OF $260,000 IN REVENUES THE FIRST YEAR. THE POLICE PATROL AND INQUIRY SYSTEMS DO NOT SHOW SUCH DRAMATIC COST SAVINGS, BUT HAVE SIGNIFICANTLY IMPROVED POLICE EFFECTIVENESS. IN KANSAS CITY, POLICE CAN INQUIRE ABOUT THREE CATEGORIES OF INFORMATION: WARRANT, STOLEN VEHICLE, AND STOLEN PROPERTY INFORMATION; CRIMINAL HISTORY INFORMATION; AND FOREWARNINGS OF PROBABLE DANGER FROM INDIVIDUALS (SUICIDAL, ARMED, MENTALLY DERANGED) OR ADDRESSES (HISTORY OF PREVIOUS DISTURBANCE). THIS HAS BEEN EXTREMELY VALUABLE TO PATROL OFFICERS. THE LOS ANGELES SYSTEM IS LIMITED TO WARRANT INFORMATION. BOTH SYSTEMS HAVE EXCEEDED EXPECTATIONS. THE CRIMINAL JUSTICE SYSTEM IS USED AS AN EXAMPLE OF THE PITFALLS OF FEDERALLY-FUNDED PROJECTS. ALTHOUGH THE SYSTEM WORKS WELL, IT IS SO EXPENSIVE THAT THE COUNTY FINDS IT DIFFICULT TO CONTINUE ITS USE WITH ITS OWN FUNDS. POLICE ARE WARNED TO CONSIDER NOT ONLY START-UP COSTS BUT ALSO LONG-TERM COSTS OF A COMPUTER OPERATION. THE ISSUES OF PRIVACY AND DECISIONMAKING ARE DISCUSSED. PRIVACY CONTROLS ARE EXPLAINED. IT IS ALSO FOUND THAT COMPUTERIZED PATROL INFORMATION ENABLES WORKING OFFICERS TO MAKE MORE DECISIONS WHILE ON PATROL AND DECENTRALIZES THE DECISION FUNCTION. CHARTS AND TABLES SUMMARIZE DATA. NOTES CONTANING REFERENCES ARE APPENDED. (GLR)