Defending DWI Charges Across New Jersey
New Jersey Ignition Interlock Device Lawyers
Contact Us Now
Ignition Interlock Devices in NJ: Requirements & Costs
Understanding Ignition Interlock Devices in New Jersey
Updated on 12/10/2025
If you’ve been arrested or convicted of DWI in New Jersey, you will likely be required to install an ignition interlock device (IID) in your vehicle. These devices can be expensive, inconvenient, and confusing — and the rules around them have changed in recent years.
This guide will explain:
- What an ignition interlock device is and how it works
- When New Jersey law requires an IID, depending on BAC and prior offenses
- Costs and NJ IID fee relief options
- Voluntary installation and the IID credit system
- Violations and penalties for tampering or failing tests
- Practical questions drivers ask about the use of an IID.
- How IID compliance affects license restoration
- How our lawyers can help reduce or challenge the IID requirements
By the end, you’ll know exactly what New Jersey law requires, how much it costs, and what steps you need to take to stay compliant and protect your driving privileges.
What Is an Ignition Interlock Device?
An ignition interlock device (IID) is a small, court-approved breath-testing unit installed in your vehicle. It requires a driver to blow into the device before starting the car and at random intervals while driving. If alcohol is detected, the vehicle will not begin to move or require you to pull over safely.
IIDs are installed only by MVC-certified vendors and must meet NHTSA standards. Devices must be serviced and recalibrated every 60 days.
The definition of ignition interlock appears in N.J.S.A. 39:4-50.17.
NJ IID Requirements: When Does the Law Require an Interlock Device?
Under N.J.S.A. 39:4-50.17, interlocks are required based on your BAC and prior offenses:
First Offense
- BAC 0.08% to under 0.10%: 3 months IID.
- BAC 0.10% to under 0.15%: 7–12 months IID.
- BAC 0.15% or higher: License suspension + 6–12 months IID after reinstatement.
Second Offense
- IID required for 2–4 years.
See our guide on Second Offense DUI Charges in New Jersey.
Third Offense
- IID required for 2–4 years.
See our guide on Third Offense DWI Charges in New Jersey.
IID duration is not tied to BAC for repeat offenders — it is mandatory.
Voluntary Interlock Installation (N.J.S.A. 39:4-50.18)
Under N.J.S.A. 39:4-50.18, New Jersey law allows some drivers to install an IID before conviction voluntarily.
Benefits include:
- Day-for-day credit against suspension or fines.
- Demonstrates good faith to the court.
- Helps drivers maintain work and family obligations.
- May allow limited conditional driving privileges during suspension.
Eligibility notes:
- Applies only to alcohol-related DWIs (not drug DUIs).
- The driver must hold a valid license at the time of installation.
- Does not apply if the offense involved injury or death.
This law expires on January 1, 2029, unless renewed.
Interlock Costs and NJ IID Fee Relief
(N.J.S.A. 39:4-50.17a)
Standard Costs
- Installation: $100–$200.
- Monthly rental: $70–$100.
- Removal fee: Charged at the end of the sentence.
Fee Relief Options
- 50% reduction if income ≤100% of the Federal Poverty Level (FPL).
- 75% reduction if income ≤149% of the FPL.
- Waivers are available for installation, maintenance, and removal costs.
Violations and Consequences (N.J.S.A. 39:4-50.19)
Under N.J.S.A. 39:4-50.19, IID violations can lead to severe penalties. Common violations include:
- Tampering with the device or asking someone else to blow.
- Missing recalibration or service appointments (required every 60 days).
- Rolling retest failures.
Penalties include:
- License suspension extensions.
- Additional fines.
- Possible jail time.
Review our DWI Penalties in New Jersey guide.
Practical Questions Drivers Ask
- What if I don’t own a car? You may still be required to install an IID in any vehicle you drive. Failure to comply can result in a 1-year extension of the suspension.
- Can I drive work or family vehicles? Only if those vehicles also have an IID installed.
- What if I move out of state? IID restrictions follow you via your driving abstract.
- What if my car is in the shop? Service intervals may not exceed 60 days; failure to comply may be treated as a violation.
What happens at removal? After your IID term, the installer must certify compliance (i.e., no tampering, missed tests, or rolling failures) before the MVC allows removal.
2024–2025 Updates: IID Credit System in NJ
- IID Credit System: Some drivers who voluntarily install IIDs early can earn “2-for-1” credit toward suspension. For example, 30 days with a voluntary IID may count as 60 days of suspension.
- Voluntary Installation Encouraged: Courts may view voluntary IID use as a demonstration of good faith and reduce disruptions.
School Zone DWI Law Repealed: No automatic enhancements for school zones since 2019, but location and child passengers may still be considered.
Review the NJ Courts IID Credit System Notice (March 2024)
NJ DWI Restoration and Ignition Interlock Compliance
Ignition interlock compliance is not just a penalty — it is often a condition of license restoration. The New Jersey MVC will not reinstate your license until:
- Your IID term is completed,
- The vendor certifies no tampering or failed tests, and
- All fines, fees, and restoration steps are satisfied.
See our guide on License Suspension & Restoration After DWI in NJ.
How a Lawyer Can Help With Interlock Requirements
Our attorneys understand the disruptive impact that IID requirements can have. We help clients by:
- Challenging the DWI or refusal charge to avoid IID.
- Negotiating shorter IID terms in court.
- Advising on a voluntary installation strategy to gain credit.
- Ensuring compliance with MVC and vendor rules to avoid violations.
- Defending against false reports of tampering or missed tests.
How Ignition Interlock Rules Affect Every Vehicle You Own — and Everyone Who Drives It
New Jersey’s ignition interlock laws apply to vehicles, not just drivers.
Under N.J.S.A. 39:4-50.17 through 39:4-50.22, once an IID is ordered, the requirement attaches to every car you own, lease, or primarily operate. This is one of the most disruptive parts of a DUI sentence, especially for families with multiple drivers and shared vehicles.
IID May Be Required on All Vehicles You Own
If you own two or three vehicles — even if you rarely drive some of them — the law may require an IID installation on each one unless the court grants a specific exemption. Programs and courts look at:
- Whose name appears on the registration
- Whether you lease, co-own, or insure the vehicle
- Whether you are a “primary operator”
For many households, this turns one IID sentence into multiple devices, each with:
- A separate installation fee
- Monthly monitoring expenses
- Regular service and calibration appointments
- A removal charge after the IID term
This becomes cost-prohibitive very quickly if you own more than one vehicle.
Everyone in Your Household Must Use the IID on Those Cars
Because the IID attaches to the vehicle:
- Your spouse must blow into the device.
- Your teenage driver must blow into the device.
- Any licensed family member or friend who uses a car that has the IID must follow the breath-test rules and rolling retests.
And here’s the critical part:
If they fail, refuse, or misuse the IID, the violation attaches to your court-ordered compliance — not theirs.
That can lead to:
- Extended IID time
- A new suspension
- Additional fines or penalties
- Delays in license restoration
This Often Disrupts Entire Household Routines
Families frequently run into real-life problems they never anticipated:
- “My child needs the car for school or sports — but now they have to use the IID.”
- “My spouse drives the family SUV more than I do — but my name is on the registration.”
- “We have a second car I barely use, but I still have to pay for another IID.”
- “Someone else failed the test and now I’m at risk of losing my license again.”
Strategic Planning Can Reduce Chaos and Cost
Before the IID order is finalized, it helps to plan:
- Which vehicle should receive the IID
- Whether one or more vehicles should be sold, transferred, or temporarily parked
- Whether the household should designate a specific car as the IID vehicle
- Whether to lease an inexpensive temporary vehicle to limit the cost to one device
- How to manage teen drivers or spouses who will have to use the IID
- How to prevent accidental violations and avoid extending the IID term
These decisions directly affect your finances, your driving privileges, and your family’s daily routine.
Ignition Interlock Device FAQ
Can I remove the interlock device early?
Only a court can authorize early removal.
Do I need the device in all my cars?
Yes. Any vehicle you drive must be equipped with an IID.
What happens if I fail a breath test?
The car will not start, and repeated failures may result in extended suspension.
Does insurance increase with IID?
Insurance rates typically rise after a DWI conviction, not because of the IID.
What if someone else drives my car?
Anyone driving your car must use the IID. Asking another person to blow into the device is a crime.
What if I don’t install the court-ordered IID?
You may face extended suspension, additional fines, and jail.
What if I don’t own a vehicle?
Courts may still impose this requirement; failure to comply can result in a one-year suspension extension.
What if the IID is removed early (accident, theft, impoundment)?
You must notify the vendor and the court immediately.
What if I have a medical condition that prevents me from using an IID?
You may request a waiver with medical documentation.
Contact us today
Call for Legal Help on Ignition Interlock Devices in New Jersey
If you’re facing a DWI in New Jersey, ignition interlock devices can disrupt your daily life. But you may have options — from negotiating shorter terms to using voluntary installation for credit.
Facing an IID requirement in NJ? Don’t face it alone. Contact a New Jersey DUI attorney at Aiello, Harris, Abate Law Group, PC today!
Call us today at (908) 561-5577 or contact us. Your initial consultation will take place over the phone, and you can schedule an appointment at one of our office locations across New Jersey.
Contact our New Jersey Ignition Interlock Device Lawyers
Meet Our Team
The Aiello Harris Abate Law Group is made of a group of professionals that are here to help you through all challenges.
Get to Know UsLegal Practice Areas
Our law firm does not stop at Ignition Interlock Devices in NJ — take a look at how we can help you overcome your legal obstacles.
View all Practice Areas