When criminal defendants are released from jail (on bond or probation), the court often wants to put measures in place to make sure they stay out of trouble. Electronic ankle bracelets can be used to monitor the location and even alcohol consumption of the wearer. When these devices monitor alcohol consumption, they are often called “continuous remote alcohol monitoring” (SCRAM) bracelets. This article covers how SCRAM bracelets work and when a court might require them.
Transdermal sampling. When consumed, alcohol is metabolized. Most is processed and expelled by the kidneys but a small amount (about 1%) is secreted from skin pores. Once the alcohol evaporates through the skin, a fuel cell within the SCRAM device measures the amount of ethanol gas within the insensible perspiration (vapor). Testing via the skin is called transdermal testing.
Monitoring agency and reporting positive samples. The SCRAM device usually obtains a transdermal sample every 30 minutes or so and sends the results to the monitoring agency. If alcohol is detected, the agency will notify the appropriate court, police department, or agency responsible for supervision. Transdermal testing does not record an immediate and exact blood alcohol concentration (BAC), but instead provides a report of drinking “incidents.”
Tampering with the device. The SCRAM device is effective at reporting alcohol usage, but other interferants can trigger an alert. Since mouthwash and cologne often have alcohol, their use can create a false-positive alert. The bracelet will also send an alert if the owner attempts to tamper with or remove the bracelet. These devices have a number of sensors that will send alerts if disrupted. The devices are waterproof to allow for bathing but extended submersion might be reported as an attempt to avoid perspiration detection.
Alcohol monitoring is most common in DUI/DWI cases and for other crimes involving alcohol. However, SCRAM devices can also be used for GPS and house-arrest monitoring.
In many cases, a judge will order a SCRAM bracelet in lieu of jail time. With the SCRAM bracelet, the judge can ensure the defendant isn’t drinking alcohol, and if the defendant does drink, the device will report a violation. A violation could result in revocation of probation or release on bail.
When a SCRAM is required, the defendant is usually responsible for picking up the cost. Installation might run anywhere from $50 to $100, and monthly monitoring fees can be up to $300 or more