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Will You Have to Install an Ignition Interlock Device if You Are Convicted of a New Jersey DWI?

Posted on November 13, 2025

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Being convicted of driving while intoxicated (DWI) in New Jersey can have serious consequences beyond just fines and license suspensions. Under the new DWI law that took effect in December 2019, most offenders are now required to install an ignition interlock device (IID) as part of their sentence. This means that even first-time offenders could face restrictions on their ability to drive unless they comply with the device installation requirement. Consulting with a skilled New Jersey DWI lawyer is essential to understand how these new laws apply to your case and to ensure your rights are protected throughout the process.

While the law offers some leniency compared to past penalties, the penalties for DWI in New Jersey remain strict, and the details of each case, such as prior offenses, blood alcohol content, or refusal to submit to testing, can significantly affect the outcome. The Kugel Law Firm can help you handle these issues and fight for the best possible result if you have been charged with DWI. Our experienced attorneys can explain your legal options, challenge questionable evidence, and work toward minimizing the impact of a conviction. Contact us today at (973) 854-0098 to schedule a consultation and get the knowledgeable defense you deserve.

Ignition Interlock Devices in New Jersey

An ignition interlock device (IID) is mounted on the dashboard in front of the passenger seat. It is connected to the car’s ignition system and designed to prevent the vehicle from starting if alcohol is detected on the driver’s breath. Before starting the engine, the driver must blow into the device and provide a breath sample. While the engine is running, the device will intermittently prompt the driver to submit additional breath samples to verify that there is no alcohol in the driver’s system.

Understanding the Voluntary Ignition Interlock Device Law and Credit System

New Jersey’s new Ignition Interlock Device (IID) law, signed by Governor Phil Murphy and effective February 19, 2024, introduces a new way for drivers to reduce penalties after being charged with certain DWI offenses. The law allows individuals to voluntarily install an IID in their vehicle before a conviction and earn credit toward their license suspension or mandatory interlock period.

The purpose of this new system is to encourage safer driving behavior and promote accountability. Voluntarily installing an IID early demonstrates a driver’s willingness to take responsibility and avoid future alcohol-related offenses. The device prevents the vehicle from starting if it detects alcohol on the driver’s breath, effectively reducing the risk of impaired driving.

Under the credit system, first-time offenders who install the device before conviction may receive day-for-day credit toward their eventual license suspension. For second or subsequent offenders, the credit is applied at a reduced rate, with one day of credit for every two days the device is installed.

It’s important to note that the voluntary IID program applies only to alcohol-related DWI charges, not to drug-related DUIs. This law reflects a shift toward prevention and rehabilitation rather than purely punitive measures, giving drivers an incentive to take proactive steps to improve safety on New Jersey’s roads.

New Jersey DWI Lawyer

Rachel Kugel

As the founder of The Kugel Law Firm, Rachel Kugel is dedicated to defending individuals charged with DWI/DUI in New Jersey and New York. Passionate about protecting her clients’ rights and reputations, Rachel offers skilled, compassionate, and results-driven representation.

  • Member of the National College of DWI Defense and DUI Defense Lawyers Association
  • Frequent speaker for AVVO Lawyernomics, NJ Bar Association, and Garden State CLE
  • Rising Star SuperLawyer honoree for three years in a row
  • Regular legal commentator on CNN, FOX News, CourtTV, MSNBC, HLN, and others
  • Brings “Mock Trial” programs to middle schools as part of her community outreach

Can An Ignition Interlock Device Be Avoided for a First Conviction of DUI?

In New Jersey, even a first conviction of DUI can lead to the mandatory installation of an ignition interlock device (IID). Since 2019, the state has implemented a DWI law requiring the installation and use of IIDs for all individuals charged with drunk driving, even on their first offense. This means that a person convicted of DUI in New Jersey may be mandated to use an IID if their blood alcohol concentration (BAC) is 0.10 percent or higher or if they refuse a breathalyzer test during a traffic stop.

The duration of the IID requirement varies depending on the BAC level for first-time offenders. Those with a BAC between 0.10-0.15 percent must use the IID for seven months to a year. For offenders with a BAC of 0.15 percent or higher, they can be required to install an IID in their primary vehicle during the license suspension period, which can last from 4 to 6 months. Additionally, they must continue using the IID for 9 to 15 months even after their license is restored.

The mandatory installation of the IID helps to reduce license suspensions for individuals charged with drunk driving while ensuring they do not drive under the influence. The New Jersey government and legislature view ignition interlock devices as a more effective alternative to combat drunk driving fatalities compared to extended license suspensions. By requiring IIDs, individuals convicted of a DUI can still use their vehicles for essential purposes, such as work, while being closely monitored to prevent intoxicated driving.

How Long Would You Have to Keep an Ignition Interlock Device Installed?

In New Jersey, driving regulations following a DWI conviction are strict and can vary based on the severity of the offense and the blood alcohol content (BAC) at the time of arrest. 

As mentioned above, individuals who had a BAC between .08 and .09 can have their driver’s license suspended until an IID is installed in their vehicle. Following the installation of an IID, their driving privileges are then restored provided that the IID remains on their vehicle for at least 90 days.

Installation of an IID in their vehicle is similarly required for those with a BAC between .10 to .14 if they want to retain their driving privileges. However, the device must be maintained for a longer period–for a minimum of seven months and can be required for up to 12 months, depending on the specific details of the case.

For drivers with a BAC of .15 or higher, the individual faces a mandatory license revocation for four to six months. During the revocation period, and for an additional nine to fifteen months thereafter, an IID must be installed and operational in the individual’s vehicle.

For individuals with a second or third offense, the consequences are more severe. They face a mandatory license revocation ranging from one to eight years. During this time, and for an additional two to four years afterward, an IID must be present in any vehicle they operate. It is crucial that the individual not drive any vehicle without an IID during the mandated period.

It’s essential to understand that there is no automatic six-month suspension for DWI offenses, and any delay in installing an ignition interlock device (IID) does not shorten the required maintenance period. For example, if a driver is mandated to maintain an IID for seven months but chooses to install the device a year after the requirement is set, they must still complete the full seven-month period. The maintenance duration is fixed and does not decrease because of installation delays. Therefore, promptly installing the IID is crucial to completing the requirement as soon as possible and regaining full driving privileges.

How Many Interlock Violations Can You Have?

An ignition interlock device (IID) is an essential tool in enhancing road safety. Installed in vehicles, it functions much like a breathalyzer, allowing only sober drivers to operate the vehicle. For individuals with DUI histories, this measure is essential in preventing repeat offenses. In New Jersey, the rules surrounding IIDs are strict, reflecting the seriousness of DUI offenses.

  • Failure to Install an IID: This violation occurs when a person mandated by a court or DMV to install an IID disregards this order. In New Jersey, under N.J.S.A. 39:4-50, individuals convicted of DUI must install an IID in their main vehicle. Non-compliance leads to severe penalties, including a year-long license suspension on top of existing penalties.
  • Tampering or Bypassing the IID: NJSA 39:4-50.19 specifically addresses the illegal tampering or circumvention of IIDs. Violations include attempts to bypass the breath test or modifying the device, and carry penalties like imprisonment, fines up to $1,000, or a disorderly persons offense. Moreover, lending a vehicle to someone mandated to use an IID is illegal and punishable.
  • Failing the Rolling Retest: IIDs require periodic rolling retests while driving, after a successful initial test. Failure to comply within the given time (usually around seven minutes) results in a temporary vehicle lockout. The device indicates the need for a retest through beeps or flashing lights. Failing the retest activates lockdown mode, preventing vehicle operation for a set period of time.

Understanding the legal implications and adhering to IID regulations is crucial. These devices play a pivotal role in repeat DUI incidents and enhancing road safety. Therefore, individuals with IIDs need to comply with the law to understand the potential legal consequences of non-compliance.

When facing charges related to ignition interlock device violations in New Jersey, several legal defenses may be available. These defenses are based on the specifics of each case and aim to address potential errors or procedural oversights that could affect the reliability of the device or the fairness of the legal process.

  • Improper Installation: One common defense is arguing that the ignition interlock device was not installed correctly. A poorly installed device can lead to inaccurate results, such as false positives, which could unfairly penalize the driver.
  • Device Malfunction: Like any electronic device, ignition interlock devices are prone to malfunctions. If there is evidence that the device was not working correctly at the time of the alleged violation, this can be a strong defense.
  • Due Process Violations: Defendants may argue that their rights were violated if they were not properly informed about the device requirement or if they were denied a fair hearing. This defense asserts that procedural mistakes compromised the legal process.
  • Procedural Errors: Sometimes, the issue might be related to how the device was used. If the device was not used as instructed or if the individual did not adhere to the operational guidelines, this could serve as a basis for defense.
  • Medical Interference: Certain medical conditions or the use of specific medications and products can interfere with device readings. If such interference caused a false positive result, presenting medical evidence could successfully contest the violation.

Each of these defenses requires a thorough examination of the facts and a clear presentation of evidence to support your case. Consulting with a legal professional who understands the nuances of New Jersey’s ignition interlock laws is advisable to effectively address these issues.

Defense/Issue Legal Basis Practical Implication
Improper Installation Device must be installed on the vehicle the person primarily operates under New Jersey MVC rules. Incorrect installation may lead to false positives or unreliable readings, which can be used as a defense.
Device Malfunction Devices must meet performance standards and be regularly serviced or calibrated. A malfunctioning device can produce inaccurate results, forming a valid defense.
Due Process Violations Drivers must be properly informed of device requirements and have access to fair hearings. Lack of proper notice or denial of due process can invalidate the violation.
Procedural Errors Misuse or failure to follow operational guidelines for the device can lead to violations. Demonstrating that procedures were not correctly followed can support a defense.
Medical Interference Certain medical conditions or medications can affect device readings. Providing medical evidence can help prove a false positive result.

How an Experienced New Jersey DUI Attorney Can Help

Operating any vehicle that does not have an ignition interlock device before the indicated period is over is prohibited under New Jersey’s DWI law. Failure to comply with the rules may result in the offender’s driver’s license being suspended for one year and other penalties as applicable by law.

At The Kugel Law Firm, our skilled New Jersey DWI lawyers, led by top-rated DWI attorney Rachel Kugel, can assist you if you have been ordered to install an IID device as part of your conviction. Our attorneys have the experience and knowledge needed to guide you through your rights and responsibilities and advocate for your best interests. To learn more about how we can help, contact us today at (973) 854-0098 to schedule a consultation.

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