The DOC operates 10 jails on Rikers Island, a 415-acre island north of La Guardia Airport in the borough of Queens, with a combined capacity that exceeds 16,000 inmates, along with six other houses of detention. As of June 30, 1996, the DOC's daily population averaged 11,979 detainees, 3,184 city-sentenced inmates, and 3,147 State inmates. The average length of stay in fiscal year 1996 was 44 days for detainees and 44 days for city- sentenced inmates. The Violence Reduction Initiative begun in 1994 has resulted in a 64-percent decrease in inmate stabbings and slashings. Methods used have included an increased number of weapons searches, special red identification cards for inmates who need to be searched more often, separate housing areas for inmates prone to violence, a computerized database to monitor and track violent incidents, and a 24-hour emergency team. A Gang Tracking Program is breaking new ground by computerizing intake information, inmate photos, physical descriptions of tattoos and other characteristics, aliases and facts concerning affiliates and enemies of gang members, along with identifying symbols, street graffiti, and known intelligence regarding gang activities and structure. Another initiative being addressed by the DOC is the reduction of officers' sick and overtime costs. By tracking and noting the reason for officer overtime, whether for nondiscretionary hospital runs, tactical operations, or the tripling of searches, managers are able to determine when, where, and why overtime costs accrue. Contemporary high-rise jails in downtown areas maintain sensitivity to urban design and local community issues by using quality exterior materials and public artwork. In an effort to address crowding, the DOC now has the ability to contract or expand its bed capacity and operate between 90 and 99 percent of available capacity. On an average day, the DOC logs more than 3,500 miles transporting inmates to courts in the five boroughs and to medical facilities as well as other jail or prison facilities throughout the city and State.