ISS stands for "Ignition Interlock System" and it means your license comes with a requirement to install a device that prevents your car from starting if alcohol is detected on your breath
An ISS restriction appears on your driver's license after a DUI or DWI conviction in most states. The device itself is a breathalyzer installed in your vehicle that you must blow into before the engine will turn over. If the device detects alcohol above a set threshold — usually 0.02 percent blood alcohol content — the car will not start. You cannot remove the device yourself, and tampering with it is a separate criminal offense.
The ISS requirement is not optional. It is a court-ordered condition of your driving privileges, and you must comply for the entire period the restriction is in place. That period varies by state and by the specifics of your conviction, but typically ranges from six months to three years. During this time, you can drive, but only with the device installed and functioning.
Key Takeaways
- ISS on your license means you must have an ignition interlock device installed in your vehicle before you can legally drive.
- The device measures your breath alcohol content and will not allow the engine to start if alcohol is detected above the legal threshold.
- You are responsible for paying the installation and monthly monitoring fees, which typically range from $60 to $150 per month depending on your state and service provider.
- Removing the device, tampering with it, or attempting to circumvent it is a criminal offense that can result in additional charges and license suspension.
- The restriction period is set by the court and varies by state, but you can petition to have it removed early if your state allows it and you meet the requirements.
How the ignition interlock device actually works
When you get in your car, you blow into the device's mouthpiece. The device analyzes your breath for alcohol and sends the result to a monitoring company. If your blood alcohol content is below the threshold set by your state — usually 0.02 percent — the device allows the engine to start normally. If your reading is at or above that level, the engine will not turn over, and the device records the failed attempt.
The device also requires rolling retests while you are driving. At random intervals after you have started the car, a light or sound will alert you to provide another breath sample. You typically have five to fifteen minutes to pull over safely and provide the sample. If you do not provide a sample or if it shows alcohol, the device logs a violation. Repeated violations can result in license suspension or other penalties.
Every month, you must bring your vehicle to the monitoring company's office so they can read the device's data. This report shows all your breath tests, failed attempts, and whether you have tampered with the device. The monitoring company sends this report to the court or your state's Department of Motor Vehicles. A pattern of violations can trigger additional legal consequences.
Who installs the device and what it costs
Your state's DMV or the court will provide you with a list of approved ignition interlock service providers in your area. You cannot choose any company — it must be one on your state's approved list. Common providers include SmartStart, Intoxalock, and Guardian Interlock, though the available companies vary by location.
Installation typically costs between $100 and $300, depending on your vehicle and the provider. Monthly monitoring fees range from $60 to $150, also depending on your state and provider. Some states cap these fees; others do not. You are responsible for paying all costs out of pocket — there is no government subsidy for this expense. If you cannot afford the installation, some providers offer payment plans, but you must contact them directly to arrange this.
You must have the device installed before you can legally drive. If you are caught driving without it when your license shows the ISS restriction, you can be charged with driving with a suspended license, which carries its own criminal penalties.
How long you will have the restriction
The length of the ISS requirement is determined by the court at the time of your DUI or DWI conviction. Most states require the device for a minimum of six months to one year for a first offense. Repeat offenses carry longer requirements — typically two to three years or more. Some states allow you to petition the court to remove the restriction early if you have maintained a clean record with the device, but this is not automatic and depends on your state's laws.
You cannot straightforward stop using the device when you think the time is up. The monitoring company will notify you and the court when your required period is complete. Only then can you schedule an appointment to have the device removed. If you remove it yourself or stop paying for monitoring before the court-ordered period ends, you will be in violation of your sentence.
What happens if you violate the ISS requirement
Violations fall into two categories: breath test violations and device tampering. A breath test violation means you either failed a test (alcohol was detected) or missed a rolling retest while driving. One or two violations might result in a warning, but a pattern of violations — typically three or more within a monitoring period — can trigger license suspension, extended device requirements, or additional criminal charges.
Tampering with the device is treated much more seriously. This includes attempting to bypass the device, disconnecting it, having someone else blow into it for you, or physically damaging it. Any form of tampering is a separate criminal offense in most states and can result in felony charges, jail time, and permanent license revocation. The device is designed to detect tampering attempts, and the monitoring company reports all suspicious activity to the court.
If you are arrested for driving under the influence while the ISS device is installed, the consequences are severe. You will face new DUI charges in addition to violations of your existing sentence, which can result in longer device requirements, extended license suspension, or incarceration.
Removing the device when your requirement ends
When your court-ordered period is complete, you must contact your service provider to schedule a removal appointment. The provider will remove the device from your vehicle, which takes about an hour. You will receive a receipt confirming removal. Keep this receipt — you may need it to show the DMV that the device has been removed.
After removal, you should verify with your state's DMV that the ISS restriction has been lifted from your license. In some states, the restriction is automatically removed once the monitoring company reports completion to the court. In others, you may need to submit the removal receipt to the DMV yourself. Contact your local DMV to confirm the process in your state.
If you believe you meet the criteria for early removal in your state, you can petition the court that issued your sentence. Early removal is not may provide, and the court will review your monitoring record. If you have had multiple violations or failed breath tests, your petition will likely be denied.
How ISS differs from other license restrictions
An ISS restriction is different from a standard license suspension or revocation. With a suspension, you cannot drive at all during the suspension period. With an ISS restriction, you can drive, but only with the device installed. Some states also issue a "hardship license" or "work permit" that allows limited driving during a suspension period, but this is separate from an ISS requirement.
You may also see other restrictions on your license related to a DUI conviction, such as a requirement to carry proof of insurance or a restriction on driving between certain hours. These restrictions are independent of the ISS requirement and may remain in place even after the device is removed. Check your license carefully to see all restrictions that explore to you.
Frequently Asked Questions
Can I drive someone else's car if I have an ISS restriction?
No. The restriction applies to you as a driver, not to a specific vehicle. You cannot legally drive any car unless it has an approved ignition interlock device installed. If you are caught driving a vehicle without the device, you can be charged with driving with a suspended license.
What if I blow into the device and it shows a false positive?
The device is calibrated regularly to prevent false positives, but they can happen. If you believe a reading is inaccurate, document the time and circumstances and contact your monitoring company when ready. They can review the data and may allow you to provide a second test. Repeated concerns about accuracy should be reported to the court.
Do I have to pay for the device if I cannot afford it?
You are legally required to have the device installed and maintained. If you cannot afford it, contact your service provider about payment plans. Some providers offer reduced rates or financing options. If you truly cannot pay, you may need to speak with the court about your situation, though the court cannot waive the requirement — only potentially adjust the timeline.
Can I get the ISS requirement removed early?
Some states allow early removal if you petition the court and meet certain criteria, such as maintaining a clean monitoring record for a set period. However, this is not automatic and depends on your state's laws and the judge's discretion. Contact the court that issued your sentence to learn whether early removal is an option in your case.
What happens if I move to a different state while I have an ISS requirement?
Your ISS requirement follows you. You must have the device installed in your new state and continue monitoring with an approved provider there. Contact your new state's DMV to learn which providers are approved and what the process is for transferring your requirement. Failure to comply in your new state can result in license suspension and additional criminal charges.