ISS stands for "Ignition Interlock System" and appears on your license when you are required to use a breath-testing device in your vehicle
An ISS restriction on your driver's license means you must install and use an ignition interlock device before you can start your car. This device measures your breath alcohol content and prevents the engine from starting if it detects alcohol above a set threshold — usually 0.02% or lower, depending on your state and the reason for the restriction.
The restriction appears as a code or notation on your license itself, typically printed on the back or in the restrictions section. Law enforcement and licensing officials use it to confirm you are legally required to have the device installed. If you drive without one when ISS is on your license, you can face additional criminal charges, fines, and license suspension.
Key Takeaways
- ISS means you must have an ignition interlock device installed in any vehicle you drive, and the device must be working before your engine will start.
- Most states require ISS after a DUI or DWI conviction, but some also impose it after refusing a breath test or for certain repeat traffic violations.
- The cost of installing and maintaining the device — usually $70 to $150 per month — is your responsibility, and you must keep it serviced on schedule.
- You can request removal of the ISS restriction only after you complete the required monitoring period, which varies by state and offense.
- Tampering with, removing, or bypassing the device is a separate crime and will result in when ready license suspension and criminal charges.
Why ISS appears on your license after a DUI or DWI
Most states impose an ISS restriction as part of a DUI or DWI sentence. The device is meant to prevent you from driving under the influence during the period when your license is suspended or restricted. Even if your license is reinstated, the ISS requirement often remains in place for months or years.
Some states also require ISS if you refused a breath or blood test during a traffic stop, even if you were not convicted of DUI. A few states impose it after multiple traffic violations or reckless driving convictions. The specific trigger depends on your state's laws and the details of your case.
The length of time you must use the device varies widely. Some states require it for 6 months; others for 1 to 3 years. Your sentencing paperwork or the letter from your state's Department of Motor Vehicles will state the exact end date or the conditions under which the restriction can be removed.
How the ignition interlock device works
When you get in your vehicle, you blow into the device's mouthpiece before starting the engine. The device analyzes your breath and either allows the engine to start or locks it. If your breath alcohol is below the threshold, the car starts normally. If it is above the threshold, the engine will not turn over, and the device logs the failed attempt.
The device also requires rolling retests while you are driving. At random intervals — usually every 5 to 15 minutes — the device will alert you to provide another breath sample. You have a set time (usually 3 to 5 minutes) to pull over safely and blow into the device. If you do not comply or fail the test, the device logs the violation and may trigger your horn or lights.
Every 30 days, you must take your vehicle to a service center to have the device downloaded and inspected. The technician checks the device for tampering and reviews your test results. If you have too many failed tests or missed service appointments, the monitoring authority is notified and your license can be suspended again.
Cost and responsibility for the device
You pay for the installation, monthly monitoring, and removal of the ignition interlock device. Installation typically costs $100 to $300, and monthly fees range from $70 to $150 depending on your state and the service provider. Some states have a list of approved vendors; others allow you to choose from any certified provider.
You are responsible for keeping the device serviced on schedule. Missing a service appointment is treated as a violation and can result in license suspension. If the device malfunctions, you must report it to the service provider and have it repaired or replaced when ready — you cannot drive without a working device.
Some states offer reduced fees for low-income drivers, and a few allow you to request a hardship exemption if the cost creates genuine financial hardship. Contact your state's Department of Motor Vehicles or the court that imposed the restriction to ask whether your situation qualifies.
How to remove the ISS restriction from your license
You cannot remove the ISS restriction early. You must complete the full monitoring period set by your state and the court. Once that period ends, you must request removal through your state's DMV or the court that imposed it.
To request removal, you will typically need to provide proof that you have completed the monitoring period, proof that the device has been removed from your vehicle, and a clean record during the monitoring period (no failed tests, missed appointments, or new violations). Some states require you to file a formal petition; others allow you to request removal by mail or online.
Processing the removal request takes 2 to 4 weeks in most states. Once approved, you will receive a new license without the ISS restriction, or a letter confirming the restriction has been lifted. Keep this documentation in case you are stopped by law enforcement.
What happens if you drive without the device or tamper with it
Driving a vehicle without an ignition interlock device when ISS is on your license is a separate criminal offense. Penalties include additional fines (often $500 to $1,000 or more), jail time, and when ready license suspension. Some states treat it as a felony if you have prior violations.
Tampering with, removing, or attempting to bypass the device is also a crime. This includes asking someone else to blow into the device for you, disconnecting the device, or using a vehicle without the device installed. Law enforcement can charge you with tampering even if the engine never starts.
If you are caught driving without the device or tampering with it, your monitoring period will restart from zero, and you may face additional court-ordered penalties. Your license will be suspended again, and you will have to reinstall the device and complete the full monitoring period once more.
State variations in ISS requirements
Every state has different rules about when ISS is required, how long you must use it, and what the monitoring process looks like. Some states require it for a first DUI offense; others only for repeat offenses or high blood alcohol levels. A few states allow judges discretion to impose it or waive it based on the circumstances.
The monitoring period also varies. Some states require 6 months of use; others require 1 to 3 years. A few states tie the length of monitoring to your test results — if you pass all tests for a certain period, you can request early removal.
If you have an ISS restriction from one state and move to another, you will need to understand how your new state treats the restriction. Some states recognize out-of-state restrictions; others require you to comply with their own rules. Contact your new state's DMV to clarify what you must do.
Frequently Asked Questions
Can someone else blow into the device for me?
No. Having someone else provide a breath sample is tampering with the device and is a separate crime. The device is designed to test your breath specifically, and the monitoring authority will know if the samples do not match your pattern. This violation will extend your monitoring period and may result in criminal charges.
What if I cannot afford the monthly fees?
Contact your state's DMV or the court that imposed the restriction and ask about hardship waivers or reduced-fee programs. Some states offer fee reductions for drivers below a certain income level. You may also ask the court to modify the terms of your sentence, though approval is not may provide.
Do I have to use the device in every vehicle I own?
Yes. The ISS restriction applies to any vehicle you drive, not just one car. If you own multiple vehicles, you must have the device installed in each one you operate. Some people choose to sell extra vehicles or designate one car as their only vehicle to reduce the total cost.
Can I get the restriction removed early for good behavior?
It depends on your state. Some states allow early removal after a set period (like 6 months of a 1-year requirement) if you have a clean record with no failed tests or violations. Others require you to complete the full term. Check your sentencing paperwork or contact the court to learn whether early removal is possible in your case.
What happens if the device breaks while I am driving?
You must pull over safely and contact the service provider when ready. Do not continue driving. Report the malfunction to the monitoring authority as soon as possible. Most states allow a grace period (usually 24 to 48 hours) to have the device repaired or replaced, but you should not drive during that time unless you have written permission from the monitoring authority.