ISS stands for "Ignition Interlock System" — a device that prevents your car from starting if it detects alcohol on your breath
An ISS notation on your driver's license means you are required by law to have an ignition interlock device installed in your vehicle. The device connects to your car's ignition and requires you to blow into a mouthpiece before the engine will start. If the device detects alcohol above a set threshold — usually 0.02 percent blood alcohol content — the car will not start.
You will see this restriction added to your license after a DUI or DWI conviction, or sometimes after a refusal to take a breath test. The specific rules about how long you must use the device, what it costs, and where you can have it installed depend on your state and the details of your case.
Key Takeaways
- ISS on your license means you must install an ignition interlock device in any vehicle you drive, and the device must be working before your car will start.
- The device typically stays in your vehicle for six months to three years, depending on your state's laws and whether this is a first or repeat offense.
- You pay for the device installation and monthly monitoring fees yourself — these costs are not covered by the state.
- Tampering with the device, having someone else blow into it, or driving a car without one installed while the restriction is active can result in license suspension and criminal charges.
- Once your required period ends, you must have the device removed by a certified technician and submit proof of removal to your state's DMV.
How the ignition interlock device actually works
When you get in your car, you will see a small device mounted on the dashboard or steering column with a tube attached. Before you can start the engine, you blow into the tube for about five to ten seconds. The device measures your breath alcohol content and sends the result to a central monitoring company.
If your breath alcohol is below the threshold set by your state — usually 0.02 percent — the device allows the ignition to engage and your car starts normally. If the reading is above that level, the ignition locks and the car will not start. The device also records every test you take, including the time, date, and result. That record is sent to the monitoring company and can be reviewed by the court or your probation officer.
Most devices also require "rolling retests" while you are driving — meaning the device will prompt you to provide another breath sample at random intervals after you have started the car. If you do not provide a sample or if the sample shows alcohol, the device will log a violation and may trigger your car's horn and lights.
How long you will need to use the device
The length of time you must use an ignition interlock device varies significantly by state and by the circumstances of your case. A first-time DUI conviction typically requires the device for six months to one year. A second offense usually means one to three years. Some states require longer periods if your blood alcohol content was very high at the time of arrest, or if you refused to take a breath test.
Your state's DMV or the court handling your case will send you a letter stating exactly when your restriction period begins and when it is scheduled to end. The period usually starts when the device is first installed, not when you were arrested or convicted. If you have violations during the monitoring period — such as failing a breath test or tampering with the device — your state may extend the requirement.
Finding a certified installer and understanding the costs
You cannot install an ignition interlock device yourself. Your state maintains a list of certified installers, and you must use one of them. You can find this list on your state's DMV website or by calling your local DMV office. Common providers include Smart Start, LifeSafer, and Intoxalock, though the available companies vary by state and region.
Installation typically costs between $100 and $300, depending on your vehicle and your location. After installation, you will pay a monthly monitoring fee — usually between $60 and $100 per month — to cover the cost of the device, the cellular connection that reports your results, and the company's monitoring services. You are responsible for all these costs. Some states allow you to request a fee reduction if you can demonstrate financial hardship, but this is not automatic.
You will also need to visit the installer monthly so they can read the device's data and may support it is working correctly. These service visits are usually quick — ten to fifteen minutes — but you must keep your appointments or you risk being reported to the court.
What happens if you violate the ISS restriction
Tampering with, disabling, or removing the ignition interlock device before your restriction period ends is a crime in every state. This includes having someone else blow into the device for you, disconnecting the device, or driving a vehicle that does not have one installed while your restriction is active.
If you are caught violating the restriction, you face criminal charges, an extended monitoring period, and when ready license suspension. Your state may also require you to install a camera-based device that photographs you during every breath test, adding to your monthly costs. A violation can also result in jail time, depending on your state's laws.
If you fail a breath test recorded by the device — meaning you drove with alcohol in your system — the monitoring company reports this to the court or your probation officer. A single failed test may not end your restriction, but multiple failures can result in an extension of your monitoring period or additional criminal charges.
Removing the device and ending the restriction
When your required monitoring period ends, you cannot straightforward remove the device yourself. You must return to a certified installer and have them remove it professionally. The installer will document the removal and submit proof to your state's DMV. Only after the DMV receives this proof will your ISS restriction be lifted from your license.
If you remove the device before your period ends, or if you fail to have it removed by a certified technician, your state will not lift the restriction and you will remain unable to renew your license. Some states also charge a removal fee, usually $50 to $100.
Once the restriction is removed, you can drive any vehicle without the device. However, the fact that you had an ISS restriction will remain on your driving record and may affect your insurance rates for several years.
Frequently Asked Questions
Can I drive someone else's car if I have an ISS restriction?
No. The restriction applies to you as a driver, not to a specific vehicle. You cannot operate any car without an ignition interlock device installed, even if it belongs to a family member or friend. Doing so is a violation and can result in criminal charges and license suspension.
What if I cannot afford the monthly monitoring fees?
Some states allow you to request a fee reduction or waiver based on financial hardship, but you must ask the court or your probation officer — the monitoring company will not reduce fees on its own. You will need to provide proof of your income and expenses. If your request is denied, you are still legally required to pay the fees or face violation charges.
Do I have to tell my insurance company about the ISS restriction?
Yes. Your insurance company will likely discover the restriction when they check your driving record, and failing to disclose it can give them grounds to deny a claim. Notify them as soon as the restriction is added to your license. Your rates will probably increase, but this is better than having a claim denied later.
Can the ISS restriction be removed early?
In some states, you can petition the court for early removal after you have completed a portion of the required period — often after six months to one year — if you have had no violations. However, this is not automatic and the court may deny your request. You will need to work with an attorney or your probation officer to file the petition.
What if my car breaks down and I need to use a rental or borrowed vehicle?
You cannot drive a rental or borrowed car unless it has an ignition interlock device already installed. If you need to rent a vehicle, contact rental companies in your area to ask if they have cars with devices already installed — some do, but availability is limited. For borrowed vehicles, the owner would need to have a device installed at their own cost, which is why most people will not allow you to borrow their car while you have an ISS restriction.