Ignition Interlock Requirements for DWI in New Jersey

What Is an Ignition Interlock Device?

An ignition interlock device is a breath-testing unit installed in a vehicle that prevents the engine from starting unless the driver provides a clean breath sample — below a set BAC threshold. It also requires periodic "rolling retests" while the vehicle is in motion. The device records all test results, and violations are reported to the state.

Who Is Required to Install an IID in NJ?

Under New Jersey's DWI law, ignition interlock requirements now apply to a broad range of DWI convictions:

• First offense, BAC 0.08–0.09%: IID required during the suspension period and for a period after license restoration.
• First offense, BAC 0.10%+: IID required during and after suspension for a longer period.
• Second and third offenses: IID required for extended periods, often years, with additional requirements.
• Breath test refusal: Refusal convictions also carry IID requirements in many cases.

The specific duration and conditions vary by BAC level, prior history, and other factors in your case.

The Practical Burden of Ignition Interlock

For most people, the IID is one of the most disruptive day-to-day consequences of a DWI conviction. It must be installed in every vehicle you own or regularly operate. Installation typically costs $70–$150. Monthly monitoring fees run $60–$100 or more. And the device introduces daily inconvenience — required breath tests before starting, rolling retests, and the need to avoid certain foods or mouthwashes that can trigger false readings.

If you share vehicles with family members, they will also be subject to the device. If you drive for work, an IID may affect your employment. Understanding exactly what you're facing — and for how long — is important.