Should You Install an Ignition Interlock Before Your New Jersey DWI Case Is Resolved?
After a DWI arrest, many drivers assume they should wait until their case is resolved before installing an ignition interlock device. For some New Jersey drivers, however, acting earlier can provide significant benefits.
Voluntary installation before conviction may help an eligible driver reduce a future license suspension and avoid the statutory DWI fine.
But installation alone is not enough. You must also obtain a restricted driver’s license from the New Jersey Motor Vehicle Commission before you begin earning credit.
The preconviction interlock benefits were introduced by P.L. 2023, c. 191, effective February 19, 2024. P.L. 2025, c. 41 further amended N.J.S.A. 39:4-50 for offenses occurring on or after April 3, 2025. The applicable provisions depend on the offense date. The interlock legislation is currently scheduled to expire on January 1, 2029.
How does the credit work?
For qualifying drivers, New Jersey law provides one day of credit against license forfeiture for every two qualifying days with both the interlock installed and the required restriction on the driver’s license.
For example, 60 qualifying days before conviction would produce 30 days of credit against an applicable suspension. A first offender with a reading of .15% or higher faces a three-month license forfeiture. If that driver has 90 qualifying days before conviction, the resulting 45-day credit would reduce that three-month forfeiture by 45 days.
The credit is not limited to first offenders.
The statute also provides credit against the one-to-two-year forfeiture for a second offense and the eight-year forfeiture for a third or subsequent offense.
However, in our practice, we have not yet seen a judge award this credit to a third offender.
Although the statutory language includes those offenders, anyone facing a third or subsequent DWI should discuss the issue carefully with counsel before relying on an anticipated credit.
First install the device. Then obtain the restricted license.
The process requires two separate steps, in this order:
Have the ignition interlock device installed. The device must be installed in one motor vehicle that you own, lease, or principally operate. Obtain the installer’s certification confirming the installation.
Within seven days after receiving the required documentation, submit the installer’s certification and the required documentation of your pending charges to the New Jersey Motor Vehicle Commission with your request for a restricted driver’s license. You must then have the restricted license issued, bearing the notation that you may operate only vehicles equipped with an ignition interlock.
Do not miss the seven-day submission deadline. The statute requires submission of the request and supporting documentation within that period; it does not expressly require MVC to issue the restricted license within seven days. If you have missed the deadline, consult your attorney promptly about how to proceed.
You receive no credit for days when the device is installed but you have not yet obtained the restricted license.
Even within the seven-day window, credit does not begin until the restricted license is issued. If you install the device on a Monday and do not obtain the restricted license until Friday, those first four days do not count. Merely scheduling an MVC appointment does not satisfy the requirement. Keep copies of the installation certification and documentation establishing when the restricted license was issued.
What if this is your first offense and your reading is below .15%?
For a first alcohol-related DWI with a breath-test reading below .15%, the ordinary penalty requires an ignition interlock rather than a fixed suspension period, although driving privileges are forfeited until installation.
There is therefore no fixed suspension for the two-for-one credit to reduce.
Early installation may still eliminate the statutory DWI fine, which ranges from $250 to $500 for a first offense depending on the reading, if you meet the eligibility requirements and obtain the restricted license before conviction. However, the cost of maintaining the device while your case is pending may outweigh that savings. Discuss the timing with your attorney before arranging installation.
Who may qualify?
The voluntary-installation provisions apply to qualifying alcohol-related DWI cases, including cases based on observations of impairment rather than a numerical breath-test reading. Eligibility requires careful review.
To avoid the statutory fine, the driver must have held a valid New Jersey driver’s license in good standing at the time of the offense and maintained a license in good standing through the date of conviction. Drivers licensed only in another state do not qualify for that relief.
The suspension credit is unavailable for drug-related DWI or when the DWI offense resulted in serious bodily injury to another person. Have your attorney evaluate eligibility before paying for installation.
What if you did not install before conviction?
Installing before conviction is not the only way to earn credit. Under the 2025 amendment, a driver who must forfeit driving privileges after a DWI conviction may install an ignition interlock in lieu of serving the forfeiture and receive one day of credit for every two days the device is installed. This alternative must be addressed through the sentencing and MVC processes. Installation alone does not authorize you to drive while MVC lists your license as suspended; the sentence and your MVC licensing status must permit driving.
The same limits apply. No credit is available if the offense caused serious bodily injury, for drug-related DWI, or for a conviction for operating a commercial motor vehicle under the influence of a controlled substance.
Installing early still offers two advantages. Credit begins accumulating before sentencing, so more of the forfeiture may already be satisfied by the time of conviction. And only installation before conviction can relieve you of the statutory DWI fine.
Does the credit apply to a breath-test refusal?
No. The two-for-one credit does not apply to the separate refusal conviction.
The 2025 law amended the DWI statute, N.J.S.A. 39:4-50, but did not amend the refusal statute, N.J.S.A. 39:4-50.4a. Its credit and fine provisions therefore apply to the DWI, not to the refusal.
If you face both charges, you may qualify for benefits on the DWI charge, but those benefits do not automatically reduce the refusal penalties. Each potential sentence must be evaluated separately.
For a first refusal, the statute provides license forfeiture until an interlock is installed. Satisfying that installation requirement is different from earning the two-for-one credit.
Does early installation eliminate every penalty?
No. Relief from the statutory DWI fine does not eliminate all court assessments, fees, surcharges, or other financial obligations. Credit against license forfeiture also should not be confused with a reduction of a separately required interlock period. Other applicable sentencing requirements remain.
What practical issues should you consider?
A restricted license allows you to drive only vehicles equipped with an ignition interlock. That can affect your ability to use a spouse’s car, a work vehicle, or a rental car.
Before deciding, consider:
The benefit available under your particular circumstances.
Installation, monthly service, and removal charges.
Whether you regularly need to drive other vehicles.
Whether you can submit the required MVC request and documentation within the seven-day deadline and promptly obtain the restricted license.
The evidence, potential defenses, and possible resolutions of your case.
Early installation should be considered as part of an overall defense strategy. The possibility of sentencing benefits does not replace a careful examination of whether the State can prove the charge.
Get advice before your court date
At Wolf Law PC, we evaluate both the defenses to a DWI charge and the steps that may help protect a client’s driving privileges.
If you have been arrested for DWI in New Jersey, seek advice early. When voluntary installation is appropriate, submitting the required MVC paperwork within the seven-day deadline and promptly obtaining the restricted license can make a meaningful difference.
This article provides general information about New Jersey law as of its publication date and is not legal advice. Reading it does not create an attorney-client relationship. The provisions discussed are found in N.J.S.A. 39:4-50, as amended by P.L. 2023, c. 191 and P.L. 2025, c. 41.
For a free consultation, contact Wolf Law today, or call/text us at (732) 741-4448.
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