ISS stands for "Ignition Interlock System" and it appears on your license when you are required to use a breath-testing device in your vehicle
An Ignition Interlock System is a device wired to your car's ignition that measures your breath alcohol content before the engine will start. If the device detects alcohol above a set limit — usually 0.02% blood alcohol content — the engine will not turn on. The ISS notation on your driver license tells law enforcement, rental car companies, and anyone else checking your license that you have this legal requirement.
The ISS requirement is almost always the result of a DUI or DWI conviction. Some states also impose it after a refusal to take a breath test during a traffic stop. The length of time you must use the device varies by state and by the specifics of your case, but typically ranges from six months to three years.
You will see "ISS" printed directly on your physical license card, usually in the restrictions section. Some states use different abbreviations — "IID" for Ignition Interlock Device is common — but the meaning is the same.
Key Takeaways
- ISS on your license means you are legally required to have a breath-testing device installed in any vehicle you drive.
- The device prevents your car from starting if it detects alcohol on your breath above the legal threshold.
- This requirement comes from a DUI or DWI conviction, or in some states from refusing a breath test.
- The duration of the ISS requirement is set by the court and varies by state, typically lasting six months to three years.
- Driving a vehicle without the device installed while ISS is on your license is a separate criminal offense in most states.
How the ignition interlock device actually works
When you get into your vehicle, you blow into the handheld device mounted on your dashboard. The device measures your breath alcohol level and sends that reading to a monitoring company. If your reading is below the legal limit, the device allows the engine to start normally.
The device also requires rolling retests — additional breath samples — while you are driving. These happen at random intervals, usually every 5 to 15 minutes after the initial start. If you fail a rolling retest, the device will log the violation and may trigger your horn or lights, but it will not shut off the engine while you are moving (for safety reasons). However, that failed test will be recorded and reported to the court or monitoring authority.
Every 30 days, you must bring your vehicle to a service center so a technician can read the device data and check that it is working correctly. This appointment is your responsibility to schedule and pay for — costs typically range from $60 to $100 per month, though this varies by state and service provider.
Who installs the device and what it costs
You cannot choose any installer. Your state's Department of Motor Vehicles or court will provide you with a list of approved vendors in your area. You must use one of those vendors. Common national providers include SCRAM, Draeger, and Intoxalock, but your state may have different approved companies.
Installation costs between $100 and $300, depending on your vehicle and the provider. Monthly monitoring and calibration fees range from $60 to $100. You pay all of these costs yourself — there is no government subsidy or reimbursement program. If you cannot afford the device, you should tell the court that imposed the requirement; some judges will reduce the duration or allow alternatives in cases of genuine financial hardship, though this is not may provide.
If you remove, tamper with, or bypass the device, you face additional criminal charges. If you drive a vehicle without the device installed while ISS is on your license, that is also a separate offense. Both violations can result in license suspension, fines, and jail time.
How long you will have ISS on your license
The duration is set by the court that convicted you or ordered the requirement. It is not automatic or based on a formula — the judge decides. Typical periods are six months to three years, but some states allow longer periods for repeat offenders or serious cases.
You cannot remove the device early just because you want to. You must complete the full court-ordered period. Some states allow you to petition the court for early removal if you have a clean monitoring record, but this requires filing a motion and attending a hearing — it is not automatic.
Once the required period ends, you must have the device removed by an approved technician. The removal itself is usually free or costs $50 to $100. After removal, the ISS notation will be removed from your license at your next renewal, or you can request an updated license when ready from your state's DMV.
What happens if you fail a breath test or miss a service appointment
A failed breath test — whether at startup or during a rolling retest — is recorded by the device and reported to the monitoring company. The company sends that report to the court or probation department overseeing your case. One failed test usually does not result in when ready consequences, but it becomes part of your record.
Multiple failures or a pattern of failures can trigger a violation report to the court. The court may then order you to appear and explain the failures. Depending on the reason and your history, the judge may extend your ISS requirement, increase monitoring, or in serious cases, revoke your license or impose jail time.
Missing a scheduled service appointment is also reported. If you miss an appointment, contact your service provider when ready to reschedule. A single missed appointment may result in a warning, but repeated missed appointments will be reported as a violation.
Driving with ISS: what you need to know
You can drive normally while ISS is on your license, as long as the device is installed and functioning. There are no restrictions on where you can drive or what time of day — the device does not limit your driving privileges beyond the requirement to have it in the vehicle.
However, you cannot drive someone else's vehicle unless that vehicle also has an approved device installed. If you need to drive a rental car, you must rent from a company that can install a device, and you must arrange that installation before you pick up the car. Many rental companies will not work with ISS requirements, so call ahead.
If your vehicle breaks down or is in the shop, you cannot drive another car without a device. You will need to arrange a ride, use public transportation, or have a device installed in a loaner vehicle. This is one of the practical hardships people face during an ISS requirement.
Frequently Asked Questions
Can I get my license back without the ISS requirement?
No. If a court ordered ISS as part of your DUI sentence, you cannot remove it before the court-ordered period ends. Your only option is to petition the court for early removal, which requires showing a clean monitoring record and convincing a judge. This is not may provide and requires filing a motion.
What if I blow into the device and it says I have alcohol when I don't?
False positives can happen, especially if you have just used mouthwash, eaten certain foods, or have a medical condition like GERD. If you believe a reading is wrong, tell your service provider when ready. They can recalibrate the device or note the dispute in your record. Document what you ate or used before the test so you have evidence if the issue goes to court.
Do I have to tell my insurance company about ISS?
Yes. You must disclose the ISS requirement to your auto insurance company. Your rates will increase significantly — often by 50% to 100% or more. Some companies will not insure you at all, so you may need to switch to a high-risk insurer. Failing to disclose it could void your coverage if you are in an accident.
What if I move to a different state while ISS is on my license?
Your ISS requirement follows you. You must transfer your license to your new state and inform them of the requirement. Your new state will recognize the court order from your original state and enforce it. You will need to find an approved service provider in your new state and continue monthly appointments there.
Can I have the device removed early if I have a job that requires driving?
Hardship is not an automatic reason for early removal, but you can petition the court. Bring documentation of your job requirements and your clean monitoring record. Some judges will grant early removal or reduce the duration for employment hardship, but this is at the judge's discretion and not may provide.