In the U.S. ankle monitors are being technically upgraded. Especially popular with judicial authorities are monitors that sound an alarm at the consumption of alcoholic beverages.

The electronic ankle monitor in the U.S., which oversees via a tracking device whether a delinquent is located at a prescribed place at a prescribed time, is almost a discontinued model. New devices are continually being developed to make more comprehensive surveillance possible. For quite some time, electronic devices that establish restricted zones have been in use — for instance, when a domestic violence offender is not permitted to come closer than a specified distance to the victim. The police, along with the victim, are alerted upon violation. The minimum distance from schools, decreed in many states for sexual offenders, can thus be policed.

Electronic ankle monitors that sound an alarm upon consumption of alcoholic beverages are enjoying growing popularity with U.S. judicial authorities. Through a membrane on the skin that regularly analyzes perspiration, the alcohol content in the blood is measured. Thus, persons whose conditions of probation include not drinking alcohol can be kept under surveillance.

In addition, the U.S. firm Home Detention Equipment and Services wants to bring a device on the market this year that can also detect marijuana and the drug speed. Until now drug offenders on parole have often had to report for periodic urine tests. According to the manufacturer, police in the future would be informed immediately about drug consumption by means of the electronic ankle monitor. A GPS tracking device reports the whereabouts at the same time.

In the background of the ankle monitor boom in the U.S. are, if nothing else, savings constraints. Since the ‘80s, increasingly stiff punishments have been imposed. While crime declined, the prisons are considered overfilled. According to the U.S. media, an inmate costs the taxpayers $35 a day — an ankle monitor, $7.