ISS stands for "Ignition Interlock System" and it means your license has a restriction requiring you to use a breath-testing device before your car will start
An ISS restriction on your driver's license indicates that you are required by law to install and use an ignition interlock device on any vehicle you drive. The device measures your blood alcohol content through a breath sample before the engine will turn over. If the device detects alcohol above a set threshold — typically 0.02% — the car will not start.
This restriction appears on your license as a condition or endorsement code, depending on your state. It is not optional: driving without the device installed, or tampering with it, is a separate criminal offense that can result in additional fines, license suspension, or jail time.
ISS restrictions are imposed by courts as part of a sentence for driving under the influence (DUI) or driving while intoxicated (DWI). The length of time you must maintain the device varies by state and by the specifics of your case — typically ranging from several months to several years.
Key Takeaways
- An ISS restriction requires you to install a breath-testing device on your vehicle before you can legally drive.
- The device will not allow your car to start if it detects alcohol in your breath above the legal threshold set by your state.
- ISS is imposed by a court as part of a DUI or DWI sentence and is mandatory, not voluntary.
- Removing, tampering with, or failing to maintain the device while under an ISS restriction is a separate criminal offense.
- The duration of the ISS requirement depends on your state's laws and the details of your conviction.
How the ignition interlock device actually works
When you sit in the driver's seat, you blow into the device's mouthpiece. The device analyzes your breath for alcohol content and displays a result within seconds. If your blood alcohol is below the threshold your state has set — usually 0.02% — the device sends a signal allowing the engine to start normally.
If your breath registers above the threshold, the device locks the ignition and the car will not start. Most devices also log the failed attempt and alert your monitoring agency. Some devices require you to wait a set period — often 15 to 30 minutes — before you can attempt another breath test.
The device also requires rolling retests while you are driving. At random intervals, the device will alert you to provide another breath sample. You have a limited time — usually five to ten minutes — to pull over safely and provide the sample. Failing to do so, or providing a sample that shows alcohol, is recorded as a violation and reported to the court or monitoring authority.
You are responsible for maintaining the device: scheduling monthly calibration appointments, paying the associated fees (typically $60 to $100 per month), and ensuring the device is always in working order. If the device malfunctions or is not calibrated on schedule, that is also reported as a violation.
Which states require ISS and for how long
All 50 states have ignition interlock laws, but the circumstances that trigger a requirement and the length of the requirement vary significantly. Some states make ISS mandatory for a first DUI offense; others only require it for repeat offenses or for higher blood alcohol levels.
The duration typically ranges from six months to three years, depending on:
- Whether this is your first, second, or subsequent DUI or DWI conviction
- Your blood alcohol content at the time of arrest
- Whether you refused a breath or blood test
- Whether anyone was injured or property was damaged
- The specific statute in your state
Some states allow you to remove the device early if you have completed a certain portion of the requirement without violations. Others require you to serve the full term. A few states offer hardship waivers that may reduce or eliminate the ISS requirement in specific circumstances — such as if you have no other way to reach your job — but these are rare and require a court petition.
Because the rules differ by state and by the details of your case, you should contact your state's Department of Motor Vehicles or the court that imposed the restriction to learn the exact duration and any options for early removal.
What happens if you drive without the device or tamper with it
Driving a vehicle without an ignition interlock device while under an ISS restriction is a criminal offense separate from your original DUI or DWI conviction. Penalties typically include additional fines, extended license suspension, and possible jail time.
Tampering with the device — disconnecting it, attempting to bypass it, or having someone else provide a breath sample for you — carries even steeper penalties. Courts treat tampering as evidence of intent to violate the court order, and sentences often include jail time in addition to fines and extended license suspension.
If you are caught driving without the device or with a tampered device, the violation is reported to the court or monitoring agency. The judge may extend your ISS requirement, impose additional criminal charges, or revoke your license entirely.
How to have the ISS restriction removed from your license
Once you have completed the full term of your ISS requirement without violations, you must petition the court or your state's DMV to have the restriction removed from your license. The process and timeline vary by state.
In most states, you will need to:
- Complete the full ISS term as ordered by the court
- Obtain a letter or certificate from the ignition interlock service provider confirming that you have completed the requirement and had no violations
- File a petition with the court that imposed the restriction, or submit the completion certificate to your state's DMV
- Wait for the court or DMV to process the request and issue a new license without the ISS restriction
Some states allow you to request early removal if you have completed a portion of the requirement — typically 50% to 75% — without any violations. You will need to file a petition with the court explaining why early removal is warranted. The judge has discretion to grant or deny the request.
Do not assume the restriction will automatically disappear from your license when the term ends. You must take action to have it removed. Until you do, you are still legally required to maintain the device.
The cost of maintaining an ignition interlock device
The total cost of an ignition interlock device includes the initial installation fee, monthly monitoring and calibration fees, and removal fees when your requirement ends. These costs are your responsibility, not the court's or the state's.
Installation typically costs $100 to $300. Monthly fees range from $60 to $100, depending on the service provider and your state. If you need the device removed before the end of your term — because you sold the vehicle or moved out of state — removal fees are usually $50 to $150.
Over a one-year ISS requirement, the total cost can range from $1,000 to $1,500 or more. Over a three-year requirement, costs can exceed $3,000. Some states offer fee waivers or reductions for low-income individuals, but you must request them through the court or your state's DMV.
Frequently Asked Questions
Can I drive someone else's car if I have an ISS restriction?
No. The ISS restriction applies to you as a driver, not to a specific vehicle. You cannot legally drive any vehicle that does not have an approved ignition interlock device installed, regardless of who owns it. Doing so is a criminal offense.
What if I move to a different state while under an ISS requirement?
You must notify the court or monitoring agency in your original state and contact the DMV in your new state. Some states have reciprocal agreements that allow you to transfer your ISS requirement; others require you to restart the process under the new state's laws. Do not assume your requirement carries over automatically.
Can I get the ISS restriction removed early?
Some states allow early removal after you have completed 50% to 75% of the requirement without violations. You must file a petition with the court that imposed the restriction. The judge has discretion to grant or deny the request, and approval is not may provide.
What happens if the device registers a violation?
Violations — such as a failed breath test, a missed rolling retest, or a failed calibration — are logged and reported to the court or monitoring agency. Depending on the number and severity of violations, the judge may extend your ISS requirement, impose additional fines, or revoke your license.
Do I have to pay for the device if I cannot afford it?
Some states offer fee reductions or waivers for low-income individuals. You must request this through the court that imposed the restriction or your state's DMV. Contact your local court or DMV to learn whether your state has a hardship program and how the process works.