man blowing into ignition interlock device to start car DUIIgnition interlock devices (IIDs) are mechanisms installed in vehicles to prevent individuals from operating a vehicle under the influence of alcohol. If the court has ordered you to install one in your car in order to get your Florida driver's license reinstated, you need to understand how they work. If you only have one DUI conviction, it's important that you understand what awaits you if you are convicted again.

At Flaherty & Merrifield, we do everything we can to secure the best outcomes for our DUI defense clients, but if an IID is in your future, we can help you navigate the process.

How Does an Ignition Interlock Device Work?

These devices are required in Florida after a second DUI conviction or after a first conviction if the driver had a BAC of .15 or above. Depending on how many convictions you have and how high your BAC was at the time of your arrest, you could be ordered to use an IID for anywhere from six months to five years.

In some ways, an IID is a good thing in that it allows you to continue to drive so that you can get to work and take care of your family. However, you are responsible for the cost of the device, which can cost up to $125 a month or more. This is prohibitively expensive for some people.

Here's an overview of how ignition interlock devices work:

  • Installation. You must work with a provider contracted by the state of Florida to install and monitor your IID. You can sometimes save money by shopping around to find a provider that offers free installation or a special rate. A certified technician installs the IID in your vehicle, connecting it to the ignition system.
  • Breath sample collection. Before starting the vehicle, you will be required to blow into a breathalyzer unit attached to the IID. This breath sample is analyzed for alcohol content.
  • Alcohol content measurement. The breathalyzer measures the alcohol content in the exhaled breath. If the detected alcohol level is below a preset threshold (usually a low, legal limit), the vehicle is allowed to start.
  • Engine locking. If the alcohol content in the breath sample exceeds the preset limit, the IID prevents the vehicle from starting. Some IIDs also require random retests while the vehicle is in operation to ensure that the driver remains alcohol-free.
  • Tamper detection. Ignition interlock devices often have tamper detection features to prevent circumvention. Any attempt to remove, bypass, or tamper with the device may trigger an alert or result in penalties.
  • Data logging. Most IIDs are equipped with data-logging capabilities. They record information such as breath test results, engine starts and stops, and any detected tampering. This data can be retrieved and reviewed by authorities during scheduled maintenance or monitoring sessions.
  • Scheduled maintenance. Regular maintenance appointments are required for calibration and data retrieval. During these appointments, the data recorded by the IID is analyzed, and the device is checked to ensure proper functioning.
  • Notification system. In case of violations, such as failed breath tests or tampering, the IID may have a notification system that alerts authorities, probation officers, or other designated individuals. This can lead to legal consequences for the individual using the device.

Ignition interlock devices serve as a preventive measure, allowing individuals with DUI convictions to maintain some level of mobility while ensuring they do not operate a vehicle under the influence of alcohol. If you are unable to pay the IID provider's fees, you might be eligible for a discount or financial aid offered by the Florida Highway Safety and Motor Vehicles (FLHSMV) department.

How Our Florida DUI Defense Lawyer Can Help

If you are facing your first DUI defense, there is a possibility that a judge will order you to install an ignition interlock device. As your lawyers, we will argue against the restriction. However, the best way to avoid an IID is to avoid a DUI conviction altogether, and that is the goal of our defense team when we represent drivers charged with DUI.

Brandy Merrifield
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Florida Criminal Defense Attorney