ACES is used to suppplement traditional computer printouts on criminals, cases under investigation, licensed drivers, and motor vehicles registered in the State. The system holds the contents of field interview cards, all felony booking sheets, parolees and juveniles on probation in the county, and all sex and narcotic registrants from the San Francisco Bay area counties. Twenty-five percent of the time ACES searches provide needed information to help crack cases. In addition, the Mobile Data Terminal System (MDT) is used to enhance street patrols and includes visual presentation of officer location, an emergency button for officer aid, and an all points bulletin display.