Understanding Ignition Interlock Requirements After a Second DUI in New Jersey

Have you pleaded guilty to or been convicted of a second DUI offense under N.J.S.A. 39:4-50 and been ordered by the court to install an ignition interlock device (IID) on your vehicle?
If so, it’s important to understand your obligations—and the consequences of failing to meet them.

When is an Ignition Interlock Device Required?

If you are convicted of a second DUI, New Jersey law requires that you:

  • Install an IID during your license suspension

  • Keep the IID installed for 1 to 3 years after your driving privileges are restored

The IID must remain on your vehicle for the entire suspension period and the post-suspension period as a condition of having your license reinstated.

How Does an Ignition Interlock Device Work?

An IID is similar to a breathalyzer but is connected directly to your vehicle. It works by:

  • Requiring you to blow into the device before starting the vehicle

  • Preventing the car from starting if your blood alcohol concentration (BAC) is above the programmed limit

  • Requesting additional breath samples while driving—usually:

    • Within 4 to 8 minutes after starting the car

    • Every 5 to 10 minutes during the trip

Whose Vehicle Must Have the IID?

Under N.J.S.A. 39:4-50.17, the IID must be installed in a vehicle you “principally operate.”
This means:

  • If you own a vehicle, you must install the device on that vehicle.

  • If you don’t own a vehicle (for example, you sold your car after your license suspension), you still must install the IID in some vehicle you intend to drive once your license is restored.

    • This could be a vehicle owned by a parent, spouse, or family member.

What Happens if You Don’t Comply?

Failing to follow IID requirements has serious consequences, including:

  • The MVC will not reinstate your license until you provide proof of IID installation.

  • If you move to another state and apply for a license there, your application could be denied if New Jersey still lists your license as suspended.

  • If you operate a vehicle without an IID when ordered to have one, you face an additional one-year license suspension under N.J.S.A. 39:4-50.19(a).

  • Tampering with or bypassing the IID is a disorderly persons offense under N.J.S.A. 39:4-50.19(b), which could result in additional legal trouble.

Final Thoughts

It’s critical to understand the rules around license suspension and IID installation in New Jersey.
Failing to comply with these requirements can delay or block your ability to drive legally.

If you have questions about your IID obligations or how to protect your driving privileges, contact our office for help.