ISS stands for "Ignition Interlock System" — a device that prevents your car from starting if it detects alcohol on your breath
When you see "ISS" printed on your driver's license, it means you are required by law to have an ignition interlock device installed in any vehicle you drive. This is a court-ordered restriction, not a suggestion. The device measures your breath alcohol level before the engine will turn over, and it keeps a record of every test you take.
ISS appears on your license after a DUI or DWI conviction in most states. It is one of several restrictions a judge can impose, and it stays on your license for a set period — usually between six months and three years, depending on your state's laws and the details of your case. During that time, you cannot legally drive any car without the device installed, even if you own multiple vehicles.
Key Takeaways
- ISS means you must have an ignition interlock device installed in your vehicle before you can drive legally.
- The device requires you to blow into a tube to prove your breath alcohol level is below the legal limit before the engine starts.
- ISS is ordered by a judge after a DUI or DWI conviction and appears on your license as a mandatory restriction.
- You pay for the device installation and monthly monitoring fees yourself, which typically range from $60 to $150 per month depending on your state.
- Once your court-ordered period ends, you must request the restriction be removed from your license at your state's DMV.
How an ignition interlock device actually works
The device is a small breathalyzer unit wired into your car's ignition system. When you get in the vehicle, you blow into the mouthpiece. If your breath alcohol content is below your state's threshold (usually 0.02% or lower), the engine starts normally. If the reading is above that limit, the car will not start, and the device records the failed attempt.
Beyond the initial startup test, most devices also require rolling retests — random breath tests while you are driving. These happen at unpredictable intervals to prevent someone else from blowing into the device at startup and then the restricted driver taking over. If you fail a rolling retest or refuse to take one, the device logs the violation and may trigger your car's horn and lights as a warning.
Every test result — passed and failed — is stored in the device's memory. Typically, a monitoring company downloads this data monthly, and a report goes to the court or your probation officer. Repeated failures or tampering attempts can result in license suspension or other penalties.
Why ISS appears on your license after a DUI or DWI
A DUI (driving under the influence) or DWI (driving while intoxicated) conviction is a serious offense. Courts use ISS as a middle ground between a full license suspension and unrestricted driving. It allows you to drive to work, school, or medical appointments while ensuring you cannot operate a vehicle if you have been drinking.
Some states make ISS mandatory for all DUI convictions. Others give judges discretion — they may order it for first offenses, or only for repeat offenders or cases involving high blood alcohol levels. A few states offer an alternative: a hardship license without ISS, but with restrictions on when and where you can drive.
The length of the ISS requirement varies. A first DUI conviction might carry six months to one year of ISS. A second or third conviction typically extends it to two or three years. Some states add extra time if your blood alcohol level was particularly high at the time of arrest.
The cost of having an ignition interlock device
You pay for the device yourself — the court does not cover it. Installation typically costs $100 to $300 upfront, depending on your vehicle and the device manufacturer. Monthly monitoring and lease fees range from $60 to $150, again varying by state and provider.
Over a full year of ISS, you could spend $800 to $2,100 in device costs alone. This is separate from fines, court costs, increased insurance premiums, and attorney fees related to your DUI conviction. Some states allow you to remove the device yourself once your court order expires, saving a removal fee. Others require a technician to uninstall it, which may cost another $50 to $100.
A few states have programs that reduce or waive device costs for people with very low income, but these are rare. Contact your state's DMV or the court that ordered your ISS to ask whether financial hardship information exists in your area.
How to get ISS removed from your license
Once your court-ordered period ends, the restriction does not automatically disappear from your license. You must request removal yourself. The process varies by state, but generally you will need to:
- Contact the monitoring company to confirm you have completed the full term without major violations.
- Request a letter or certificate of compliance from the monitoring company.
- Visit your state's DMV in person with that certificate and your current license.
- Pay a small fee (usually $10 to $50) to have the restriction removed.
Some states allow you to mail in the certificate and fee. Others require an in-person visit. A few states automatically remove ISS from your record once the court order expires, but you should still verify this by checking your license online or calling the DMV.
If you have multiple violations during your ISS period — failed breath tests, missed rolling retests, or tampering — the court may extend your requirement. In rare cases, a judge can order permanent ISS or a longer suspension instead.
What happens if you drive without the device or tamper with it
Driving a vehicle without an ignition interlock device while ISS is on your license is a criminal offense in every state. You can face additional fines, jail time, license suspension, and an extended ISS requirement. Even a single violation can result in six months to one year added to your original term.
Tampering with the device — disconnecting it, trying to bypass it, or having someone else blow into it — is also illegal. Modern devices are designed to detect these attempts and record them. If the monitoring company reports tampering to the court, you will face serious consequences, including possible arrest.
If you are struggling with the device or believe it is malfunctioning, contact the monitoring company or your attorney. Do not attempt to remove or disable it yourself.
ISS compared to other license restrictions
ISS is one of several restrictions that can appear on your license after a DUI. Understanding the difference helps you know what you are legally allowed to do:
| Restriction | What it means | How long it typically lasts |
|---|---|---|
| ISS | You must have an ignition interlock device in any vehicle you drive. | 6 months to 3 years, depending on state and conviction details. |
| License suspension | You cannot drive at all, even with restrictions. Your license is invalid. | 3 months to 1 year for a first offense; longer for repeat offenses. |
| Hardship license | You can drive only to work, school, medical appointments, or court. No recreational driving. | Duration of suspension, or until full license is restored. |
| License revocation | Your license is permanently cancelled. You must reapply from scratch after a waiting period. | Permanent until you reapply; reapplication may take 1 to 5 years. |
Some states stack these restrictions — for example, you might serve a suspension first, then have ISS for the next year. Others use them as alternatives. Your specific situation depends on your state's laws, your criminal history, and the judge's decision.
Frequently Asked Questions
Can I drive someone else's car if it doesn't have an ignition interlock device?
No. ISS on your license means you cannot legally drive any vehicle without the device installed, regardless of who owns it. Driving someone else's car without the device is a criminal violation and can result in arrest, additional fines, and an extended ISS requirement.
What if I fail a breath test while driving?
A failed rolling retest is recorded by the device and reported to the monitoring company. One failure usually triggers a warning but not when ready legal consequences. However, repeated failures or a pattern of violations can result in the court extending your ISS requirement or suspending your license entirely. Your probation officer or the court may also be notified.
Do I have to pay for the device if I don't drive?
If you do not drive during your ISS period, you technically do not need the device installed. However, you still cannot legally operate any vehicle. Some people choose not to drive rather than pay for the device, but this is a personal choice — the state does not refund or waive the cost. If you later decide to drive, you must have the device installed before starting the engine.
Can ISS be removed early?
In some states, you can petition the court for early removal if you have a clean record during your ISS period — no failed tests, no violations, no missed monitoring appointments. The judge has discretion to grant or deny the request. Early removal is not may provide and typically requires an attorney and court filing fees.
What if the device malfunctions and won't let me start my car?
Contact the monitoring company when ready. They can troubleshoot the device remotely or schedule a technician visit. If the device is genuinely defective, the company will repair or replace it at no extra cost. Keep documentation of the malfunction in case you need to explain a missed appointment or work absence to your employer or the court.