An account is given of the SCRAM (secure continuous remote alcohol monitor) anklet developed in the United States by AMS (Alcohol Monitoring Systems) to monitor alcohol offenders. Relying on the fact that 1 per cent of alcohol leaves the body through the skin, jets of air fired at intervals vaporise any alcohol present and measure its concentration. The readings are relayed to AMS via a modem installed in the wearer's home. The system is now used in most parts of the US as an alternative to jail to monitor drink-driving or other offenders who have been required to abstain from drinking. AMS report a 70 per cent compliance with the terms of probation and bail and an impressive reduction in accidents and injuries has been achieved in some states. The problems of avoidance strategies and false positives are discussed. The different patterns in readings caused by external contaminants are outlined and the suggestion made that disputed alerts could be subject to breath or urine tests. A number of court cases are noted. Further developments of the concept are considered.
Abstract