ISS stands for "Ignition Interlock System" and appears on your license when you are required to use one
ISS is a court-ordered notation that tells police, employers, and licensing officials that you must install and use an ignition interlock device in any vehicle you drive. The device prevents a car from starting if it detects alcohol on your breath. Most states add this notation after a DUI or DWI conviction, and it stays on your license for the duration of the court's requirement — typically one to three years, depending on the offense and your state's laws.
The ISS marking itself is not a punishment; it is a record that you are under a specific driving restriction. The actual restriction is the device requirement, not the license notation. However, the marking on your license makes the restriction enforceable and visible to law enforcement if you are stopped.
Key Takeaways
- ISS on your license means a court has ordered you to install an ignition interlock device in any vehicle you operate.
- The device measures your breath alcohol level before the engine will start, and you must blow into it periodically while driving.
- ISS requirements are set by the court and vary by state, but typically last one to three years from the conviction date.
- Driving a vehicle without an interlock device installed when ISS is on your license is a separate criminal offense in most states.
- Once your court-ordered period ends, you must request removal of the ISS notation from your license at your state's DMV.
How an ignition interlock device actually works
An ignition interlock is a small breathalyzer unit wired into your vehicle's ignition system. Before you can start the engine, you blow into the device's mouthpiece. If your blood alcohol content (BAC) is below the legal threshold — usually 0.02 percent, which is lower than the 0.08 percent DUI limit — the device allows the engine to start. If your BAC is above that level, the engine will not turn over.
The device does not stop there. While you are driving, it will prompt you to provide breath samples at random intervals — typically every 5 to 15 minutes. These rolling retests may support you are not drinking while behind the wheel. If you miss a retest or fail one, the device logs the violation, and your license can be suspended further.
You pay for the device installation and monthly monitoring yourself. Costs vary by state and provider, but installation typically runs $100 to $300, and monthly monitoring fees range from $50 to $150. These are in addition to any fines or court costs from your conviction.
When ISS appears on your license and how long it stays
ISS is added to your license after a DUI or DWI conviction when the court orders an ignition interlock requirement as part of your sentence. Some states impose it automatically for all DUI convictions; others leave it to the judge's discretion. A few states use it as an alternative to license suspension — you can keep driving if you install the device, rather than losing your license entirely.
The length of the ISS requirement depends on your state's law and the specifics of your case. A first offense typically requires the device for one year; a second offense within a certain period (often five to ten years) may require two to three years. Some states extend the requirement if you fail a retest or miss a monitoring appointment.
The ISS notation remains on your license for as long as the court's requirement is in effect. Once that period ends — for example, after one year of successful compliance — you must contact your state's DMV to request removal. The notation does not disappear automatically. You will need to provide proof that your court-ordered period has ended, which usually means a letter from the interlock provider or a court document.
What happens if you drive without the device when ISS is on your license
Driving any vehicle without an ignition interlock installed when ISS is on your license is a separate criminal offense. Penalties vary by state but typically include fines of $500 to $1,500, additional jail time, an extended ISS requirement, or permanent license revocation. Law enforcement can discover the violation if they pull you over and run your license, or if you are in an accident and the police investigate.
Some states use monitoring technology that alerts authorities if a vehicle registered to you is driven without the interlock active. Others rely on police enforcement during traffic stops. Either way, the risk is substantial — you are facing new criminal charges on top of your original conviction.
The only legal exception is if you are driving a vehicle that belongs to someone else and that person does not know about your ISS requirement. However, this is a narrow defense and difficult to prove. The safest approach is to drive only vehicles with an installed and functioning interlock device.
Removing ISS from your license after the requirement ends
When your court-ordered interlock period is complete, the ISS notation does not automatically disappear from your license. You must request removal yourself. Contact your state's DMV or driver licensing agency and provide documentation that your requirement has ended. This usually means a letter from the interlock service provider confirming that you have completed the required period, or a court order stating that the requirement is satisfied.
Some states allow you to request removal online through their DMV portal; others require you to visit in person or mail in your request. Processing times vary from a few days to several weeks. Once approved, you will receive a new license without the ISS notation, or your current license will be updated in the system.
If you fail to request removal and continue to have ISS on your license after your requirement ends, it can affect employment, insurance rates, and your ability to rent vehicles. It is worth following up to may support the notation is cleared once you are no longer legally required to use the device.
ISS versus other license restrictions and notations
ISS is one of several notations that can appear on your license. Other common ones include SR-22 (proof of financial responsibility after an accident or violation), CDL (commercial driver's license), medical restrictions (corrective lenses, hearing aids), and organ donor status. Unlike ISS, most of these are not criminal restrictions — they are either administrative requirements or voluntary designations.
ISS is unique because it is a court-ordered restriction tied to a criminal conviction. It is more serious than a straightforward notation and carries legal consequences if violated. If you see other codes or restrictions on your license that you do not understand, your state's DMV website or a local driver licensing office can explain what each one means.
Frequently Asked Questions
Can I get my license back without installing an interlock device?
That depends on your state and the judge's order. Some states allow you to choose between license suspension and an interlock requirement; others make the interlock mandatory. If the court has ordered ISS on your license, you cannot legally drive without the device installed. Your only option is to follow the court's requirement or appeal the decision through the legal system.
What if the interlock device malfunctions or gives a false reading?
Interlock providers are required to maintain and calibrate devices regularly. If you believe your device is faulty, contact the service provider when ready and request a calibration check or replacement. Document the malfunction in writing. If the device fails and you cannot drive, contact your attorney or the court — some judges will grant temporary relief if the malfunction is documented and not your fault.
Does ISS on my license affect my car insurance rates?
Yes, ISS typically results in higher insurance premiums because it signals a DUI conviction to insurers. You may also be required to carry an SR-22 form, which is proof of financial responsibility. Shop around with multiple insurers, as rates vary. Some companies specialize in coverage for drivers with DUI convictions and may offer better rates than others.
Can I drive someone else's car if they do not have an interlock device?
No. If ISS is on your license, you are legally prohibited from driving any vehicle without an interlock device installed, regardless of who owns it. This applies even if the owner gives you permission. The only exception is if you are a passenger and not operating the vehicle.
How do I know when my ISS requirement ends?
Your court documents or sentencing order will specify the end date of your interlock requirement. Your interlock service provider will also track this and notify you when the period is complete. Mark the date on your calendar and contact your state's DMV about 30 days before it ends to begin the removal process, so the notation is cleared promptly.