The three required elements of effective AVL include the ability to determine the location of the vehicle; the ability to communicate the vehicle location to those who need to know; and the ability to translate the vehicle's location, generally computed in latitude and longitude, into a format meaningful to the dispatcher. Methods available to locate the vehicle accurately include dead reckoning, Long Range Navigation (LORAN), and the Global Positioning Satellite (GPS) system. The police department in Schaumberg, Ill., has been operating the first law enforcement GPS AVL since January 1992. Although no quantitative study has been performed to determine how much this system has reduced response times in Schaumburg, AVL is considered an integral part of the operation and has definitely had an influence on police officer safety. Potential benefits include support of hazardous situation management, a dramatic reduction in the use of voice radio in the dispatch process, and documentation of the sequence of events in an incident to augment the testimony of law enforcement personnel. AVL can also help larger police fleets increase the efficiency of their vehicle use, thereby helping police agencies avoid the need to purchase additional vehicles. Illustration and addresses and telephone numbers of five vendors