The first, conducted in Kansas City, Mo., in the early 1970's, tested the view that routine patrols in marked police cars prevents crime. Results indicated, however, that this strategy had little crime deterrent value. The second study of domestic violence, undertaken in Minneapolis in the early 1980's, compared the deterrence effectiveness of mediation, referral, and arrest. In cases of minor domestic violence, fewer subsequent incidents of violence were found to occur if the offender was arrested. The final study examined the effectiveness of oneand two-officer patrols in San Diego, Calif., in the 1970's. One-officer patrols were found to have equal performance, increased safety, and greater savings in costs.