ISS stands for "Ignition Interlock System" — a device that prevents your car from starting if it detects alcohol on your breath
If your driver's license has an ISS restriction printed on it, you are required by law to have an ignition interlock device installed in your vehicle before you can drive. This restriction appears on licenses issued after a DUI or DWI conviction, and it is a condition of your driving privileges, not a suggestion. You cannot legally operate a vehicle without the device installed, even if you feel you are safe to drive.
The device works like a breathalyzer built into your car's ignition system. Before the engine will start, you blow into the device. If your blood alcohol content is below the legal threshold (usually 0.02 percent), the car starts normally. If the reading is above that level, the ignition locks and the vehicle will not start. Some devices also require you to provide breath samples while driving, to prevent someone else from blowing into the device before you take the wheel.
The length of time you must use an ignition interlock device varies by state and by the specifics of your conviction. Some states require it for six months; others require it for several years. Your license paperwork will specify how long the restriction applies to you.
Key Takeaways
- An ISS restriction on your license means you must have an ignition interlock device installed in any vehicle you drive.
- The device measures your breath alcohol content before allowing the engine to start, and will not permit ignition if alcohol is detected above the legal threshold.
- ISS restrictions are imposed after DUI or DWI convictions and are a legal requirement, not optional.
- The duration of the restriction depends on your state's laws and the details of your conviction, and your license will show the end date.
- You are responsible for paying the installation and monthly maintenance costs of the device, which typically range from several hundred to over a thousand dollars per year depending on your state and provider.
Why ISS appears on your license after a DUI or DWI
Courts and state licensing agencies impose ISS restrictions as a safety measure and a condition of keeping your driving privileges after an alcohol-related driving offense. Rather than suspend your license entirely, many states allow you to continue driving for work, school, or essential purposes — but only with the interlock device installed. This gives you limited mobility while protecting other drivers from the risk of impaired driving.
The restriction is mandatory in most cases, not something you can negotiate away. If your license shows an ISS code, you do not have the option to drive without the device. Attempting to do so is a separate criminal offense in most states and will result in additional penalties, fines, and license suspension.
How to install an ignition interlock device
Your state's Department of Motor Vehicles or the court that handled your DUI case will provide you with a list of certified ignition interlock service providers in your area. You must use one of these approved vendors — you cannot install an aftermarket or uncertified device and have it count toward your requirement.
Contact a provider on the approved list and schedule an installation appointment. The technician will install the device in your vehicle, usually in under an hour. You will pay an installation fee at that time, typically between $100 and $300. After installation, you will also pay a monthly monitoring fee, usually between $60 and $100 per month, to cover the cost of calibration checks and data reporting to the state.
The device must remain installed and functioning for the entire duration of your restriction period. If the device malfunctions or is tampered with, you must report it to your service provider when ready. Tampering with or removing the device is a criminal offense and will result in serious penalties.
What happens during the restriction period
While your ISS restriction is active, you must blow into the device every time you want to start your car. The device records all test results and sends them to your state's licensing agency or to the court. These records are reviewed to may support you are complying with the restriction.
If you fail a breath test (meaning your blood alcohol content is above the legal threshold), the device will log that failure. Repeated failures or missed tests can result in license suspension, additional fines, or an extension of your restriction period. Some states also require you to attend alcohol education or treatment programs while the device is installed.
You are responsible for keeping the device calibrated and maintained. Your service provider will schedule regular calibration appointments, usually every 30 to 60 days. You must attend these appointments or the device will stop functioning and your vehicle will not start. Missing calibration appointments is treated as non-compliance with your restriction.
When the ISS restriction ends
Your license will show the end date of your ISS restriction. On that date, you can contact your service provider to have the device removed. You will pay a removal fee, typically between $50 and $150. Once the device is removed and your service provider confirms removal to the state, the ISS code will be removed from your license.
Some states allow you to request early removal of the device if you have maintained a clean record during the restriction period — meaning no failed breath tests, no missed calibration appointments, and no new traffic violations. If your state offers this option, you can petition the court or the DMV to shorten your restriction period. However, early removal is not automatic and is granted only at the discretion of the court or licensing agency.
The cost of an ignition interlock device
The total cost of maintaining an ignition interlock device over the course of your restriction period includes installation, monthly monitoring fees, and calibration visits. Installation typically costs $100 to $300. Monthly monitoring fees range from $60 to $100 per month. If your restriction lasts one year, you can expect to spend between $800 and $1,500 total. Longer restrictions will cost proportionally more.
Some states or courts offer payment plans or fee waivers for people with financial hardship, though these are not may provide. Contact your service provider or the court that imposed your restriction to ask whether financial information is available in your situation.
Frequently Asked Questions
Can someone else blow into the device so I can drive?
No. Many modern devices include a camera or require rolling retests while you are driving to prevent this. If the device detects that someone other than you provided the breath sample, it will record a violation. Attempting to circumvent the device is a criminal offense and will result in additional penalties and license suspension.
What if I need to drive a vehicle that does not belong to me?
You can only drive vehicles that have an approved ignition interlock device installed. If you need to borrow someone else's car, that vehicle must have the device installed before you can legally drive it. Some people install devices in multiple vehicles if they regularly drive more than one car.
Does the ISS restriction appear on my record permanently?
The restriction appears on your license only while it is active. Once the device is removed and the restriction ends, the ISS code is removed from your license. However, the DUI conviction itself remains on your driving record and criminal record. The conviction does not disappear, but the active restriction does.
What happens if I move to a different state while my restriction is active?
You must comply with the ignition interlock requirement in your new state as well. Contact the DMV in your new state and the court that imposed the restriction to understand how your restriction transfers. You will need to install a device in your new state and may need to continue reporting to your original state's licensing agency.
Can I get my license back without installing the device?
No. If your license shows an ISS restriction, you cannot legally drive without the device installed. The only way to remove the restriction is to install the device, maintain it for the required period, and comply with all testing and monitoring requirements.