Regarding supply-side enforcement, a major task of law enforcement resources is to increase drug unavailability. At the very least, the police should act immediately to suppress the open-air drug markets that spring up whenever the police are distracted by other duties. In most urban areas, greater efforts in this direction could drive much of the dealing indoors, where a large percentage of potential customers are afraid to go. The incarceration of drug dealers and the forfeiture of their assets are other means of reducing the availability of drugs. Regarding demand-side enforcement, routine urinalysis for those arrested for any of the typical drug-related crimes must be institutionalized. Maintenance of a urine clean of cocaine, heroin, and PCP must be a requirement for all those released on bail or, after conviction, are placed on probation or released on parole. A positive urine sample must reliably and immediately mean being jailed. Another aspect of demand-side enforcement is requiring treatment as part of a sentencing disposition. Although many believe that compulsory treatment is ineffective, research shows that this is not the case. By focusing on the heavy drug users that contact the criminal justice system, those who do the most to support the illegal drug market can be removed from the market through incarceration or treatment that leads to abstinence.