Ignition Interlock Devices

February 20, 2015

Mothers Against Drunk Driving (MADD) has given the state of Florida four stars out of five for its prevention of drunk driving. The only fact prevented Florida from getting five stars is that the state does not require ignition interlock devices on the cars of every person convicted of driving under the influence. MADD’s other requirements for a five-star score include: conducting sobriety checkpoints, enhanced penalties for child endangerment, low rates of blood alcohol content (BAC) test refusal, and revoking driver’s licenses.

What Is an Ignition Interlock Device?

An ignition interlock device (IID) is a device that prevents a car from starting if the driver’s BAC is greater than 0.025 percent. Basically, an IID is a Breathalyzer for your car. The driver must breathe into it to start the car. Five minutes later, the driver must breathe into it again, and every thirty minutes thereafter. The data collected is sent to the Florida Department of Motor Vehicles.


Florida law provides that, for certain DUI offenses, drivers must install IIDs in their vehicles. The devices must be installed on any vehicles that are individually or jointly leased or owned by the convicted driver, and that are routinely operated by that driver. The interlock will be installed for different lengths of time, depending on the circumstances of the offense:

DUI OffenseIID Requirement
First DUI, BAC of 0.08 to 0.14 percentJudge may order installation for six months instead of a ten-day vehicle impoundment
First DUI if a minor is in the car or BAC is over 0.15 percentUp to six months
Second DUIAt least one year
Second DUI if a minor is in the car or BAC is over 0.15 percentAt least two years
Third DUIAt least two years
Four or more DUIsAt least five years (as a condition of a hardship license)

IIDs are not required to be installed on vehicles that are owned by the convicted driver’s employer and that the driver uses in the scope of his or her employment. The driver must notify his or her employer of the driving restriction. However, IIDs must be installed if the driver owns or controls the business that owns the vehicle.

If a driver is convicted of a DUI offense during the period when he or she is required to use an IID, his or her license will be revoked for five years.


IIDs are paid for by the convicted person. However, if the driver is unable to pay, a portion of the fine paid for violation may be allocated to paying for the interlock. IIDs cost $70 for installation, plus a refundable deposit of $100. Additionally, there is a monthly fee of $67.50 for monitoring and monthly calibration. For calibration, drivers must take their vehicles to a calibration facility for a forty five minute appointment.

If you have been convicted of driving under the influence, the advice of an experienced DUI defense attorney is critical. Penalties for driving under the influence are serious, ranging from suspension of a license to installation of an IID to imprisonment. Please contact West Palm Beach criminal defense attorney William Wallshein for a free initial consultation.