Electronic Monitoring Devices
Oakland County, MichiganCommunity CorrectionsElectronic Monitoring Devices

Electronic Monitoring Devices

Pretrial - Felony - Misdemeanor

Program Information

For more intensive monitoring, in conjunction with Pretrial Supervision, a defendant may be court ordered to an electronic monitoring (EM) device. EM may be used to restrict or supervise a defendant's movements or to monitor a defendant's alcohol consumption. 

The following are types of EM devices utilized by Oakland County Community Corrections Division when ordered by the court:

  • Global Positioning System (GPS)
  • Transdermal Alcohol Monitoring
  • Portable Alcohol

rules and regulations  of the Pretrial Supervision Tether Unit

Transdermal Alcohol Tether

These devices use transdermal (through the skin) analysis to determine the defendant's Blood Alcohol Content (BAC).  They also monitor body temperature and proximity between the leg and device which are features designed to detect attempts to tamper with or obstruct the unit.  

Requirements for transdermal include:

  • that all rules and regulations of the Pretrial Supervision Tether Unit are followed

Global Positioning System (GPS)


The defendant's movements are tracked via satellites and reported at regular intervals, in the event of a violation, the defendant's movement is reported in as close to real time as possible. Exclusion zones for areas such as a victim's home, work, school or church, are programmed into a map with a predetermined radius. If the defendant enters one of these exclusion zones, the victim and GPS staff are notified, allowing the victim to enact a safety plan.  GPS may be used in, but not limited to, cases involving a victim such as Domestic Violence or Criminal Sexual Conduct.

Requirements for GPS include:

  • a stable address
  • a standard power source
  • a curfew to allow adequate time for the GPS device to fully charge
  • that all rules and regulations of the Pretrial Supervision Tether Unit ae followed

EM devices are provided through third party vendors.  Devices may be installed at the vendors location or prior to the defendant's release from custody.

Portable Alcohol

This device is a portable breathalyzer which tests the defendant for alcohol. The device is portable and does not require the installation of any additional hardware or software on the defendant. The device may be programmed to require tests at scheduled times or randomly throughout the day.  The equipment employs facial recognition technology to ensure the intended person in testing and GPS technology which provides a location point for each test submitted. 

Requirements for Breathalyzer include:

  • that all rules and regulations of the Pretrial Supervision Tether Unit are followed

All EM options are provided by third party vendors.  The costs of these systems are the responsibility of the defendant per MCR 6.106.  Costs will vary based on the type of EM required.

**Further information can be provided by calling 248-451-2310 option 5 / email: commcorr@oakgov.com**