ISS stands for "Ignition Interlock System" and appears on your license when you have been convicted of driving under the influence
The ISS designation on a Florida driver's license tells law enforcement and others that you are required to use an ignition interlock device in any vehicle you drive. This device prevents a car from starting if it detects alcohol on your breath. The marking is not optional — it is a court-ordered requirement tied to your conviction.
Florida adds this notation to your license so that police officers can see at a glance that you have this restriction, and so that anyone checking your driving record knows about it. If you drive a vehicle without the device installed when your license shows ISS, you are driving with a suspended license, which carries serious penalties.
Key Takeaways
- ISS on your Florida license means you must have an ignition interlock device installed in any vehicle you operate.
- The device is court-ordered as part of a DUI conviction and is not something you can choose to skip.
- Driving without the device when your license shows ISS is treated as driving with a suspended license.
- The ISS notation stays on your license for the entire period the court has ordered the device, which varies based on your conviction.
How the ignition interlock device works
An ignition interlock device is a small breathalyzer connected to your car's ignition system. Before the engine will start, you blow into the device. If it detects no alcohol or alcohol below the legal limit, the car starts normally. If it detects alcohol, the engine will not turn over.
The device also requires you to provide breath samples while driving — typically every 30 to 60 minutes after the engine starts. These rolling retests prevent someone from having another person blow into the device at startup and then drinking while driving. If you miss a retest or fail one, the device logs the violation and may trigger your horn and lights.
You pay for the device installation and monthly monitoring yourself. Costs vary by provider but typically range from around $60 to $150 per month, plus an initial installation fee. The device records all test results and violations, and those records are sent to the court and to the Florida Department of Highway Safety and Motor Vehicles.
How long ISS stays on your license
The length of time you must use an ignition interlock device depends on your specific DUI conviction and what the court ordered. For a first DUI conviction in Florida, the court typically orders the device for a minimum of six months. For a second or subsequent conviction, the period is longer — often one to three years or more.
The ISS notation remains on your license for the entire period the court has set. Once you have completed the required time and the device has been removed by the provider, you can request that the notation be removed from your license. You will need to provide proof from the device provider that you completed the program, and then contact the Florida Department of Highway Safety and Motor Vehicles to have your license updated.
What happens if you drive without the device
If your license shows ISS and you operate a vehicle without an ignition interlock device installed, you are driving with a suspended license. This is a separate criminal offense in Florida, distinct from the original DUI conviction. You can be arrested, fined, and face additional jail time.
The only exception is if the court has explicitly granted you a waiver or exemption from the device requirement — for example, if you have a medical condition that prevents you from using it, or if you are driving a vehicle owned by your employer that is used only for work and has been registered with the court. straightforward choosing not to install the device is not an exception.
Removing ISS from your license after completion
After you have completed the court-ordered period and the device has been removed, the ISS notation does not automatically disappear from your license. You must take steps to have it removed.
First, contact your ignition interlock device provider and request a letter or certificate of completion. This document proves that you finished the required monitoring period without major violations. Then, visit your local Florida Department of Highway Safety and Motor Vehicles office or submit your completion documentation by mail. Bring or send your current license, the completion letter, and any other documents the office requests. There is typically no fee to remove the notation once you have met the requirements.
Frequently Asked Questions
Can I get a hardship license while ISS is on my license?
A hardship license allows you to drive to work, school, or medical appointments when your license is suspended. If your license shows ISS, you can still request a hardship license, but you must still have the ignition interlock device installed in any vehicle you drive, even under the hardship permit. The device requirement does not go away.
What if I fail a breath test while the device is monitoring me?
A failed test is recorded by the device and reported to the court. One or two failures may not result in when ready consequences, but multiple failures can lead the court to extend your device requirement, suspend your license further, or order additional penalties. The exact response depends on the court's rules and your case.
Can someone else drive my car if I have ISS on my license?
Yes, someone else can drive your vehicle as long as the ignition interlock device is installed. However, if they are driving your car and fail a breath test, that failure is recorded and reported to the court under your name and license. You are responsible for the device and its results.
Does ISS affect insurance rates?
Yes. An ignition interlock requirement signals to insurance companies that you have a DUI conviction. Most insurers will increase your rates significantly or may refuse to insure you at all. You may need to contact insurers that specialize in high-risk drivers.