Will I be Required to Install an Ignition Interlock Device After a DWI Conviction in North Carolina?

Charlotte DWI Lawyer Brad Smith answers the question: “Are breath test results always accurate?”


A driving while impaired (DWI) conviction carries harsh penalties and lasting consequences. One of the penalties is the suspension of a driver’s license.

When your driver’s license is suspended, you need to have an ignition interlock device installed in your vehicle before your license can be reinstated.

However, not all types of DWI convictions require an ignition interlock device in the vehicle. Speak with our DWI/DUI defense attorneys at Arnold & Smith, PLLC, if you have been charged with an impaired driving offense in North Carolina.


cocktail-Charlotte-Monroe-Lake-Norman-DWI-Lawyer-225x300What is an Ignition Interlock Device (IID)?

An ignition interlock device (IID) is a device designed to measure alcohol concentration in a driver’s blood. The device records the results every time a driver blows into it.

When an ignition interlock is installed after a DWI conviction, the driver must blow into the device to start their car. If the driver blows a BAC over the allowable limit, the device will stop any attempt to start the vehicle.

The IID also requires the driver to provide breath samples while the vehicle is running. If a driver fails to provide a required sample or the device registers a positive result, the vehicle will shut down. All interlock violations are electronically recorded and sent to the North Carolina Department of Motor Vehicles.

There are many potential problems with ignition interlock devices that may result in a false positive reading.


When is an Ignition Interlock Device Required After a DWI Conviction?

The DMV requires drivers to install an ignition interlock after the required suspension period is completed. A driver may be eligible to restore their driver’s license after a DWI conviction by installing an ignition interlock device if:

  • Their BAC exceeded .15%;
  • They were convicted of another drunk driving offense within seven years of the offense for which their driver’s license was suspended; or
  • They were punished for DWI at aggravated level one.


How to Avoid Interlock Violations?

Interlock violations could cause your driving privileges to be revoked. However, before the DMV revokes your driving privileges after violations of an ignition interlock, you still have a chance to defend yourself at a violation hearing.

Keep a diary to record when the ignition interlock showed a false positive result. Write down the date and time of the false positives and what might have caused a false positive result (chewing gum, consuming food, using mouthwash or breath freshener, etc.).

Drivers who are required to install an ignition interlock device must have monthly maintenance appointments. Missing a maintenance appointment will result in an interlock violation, which may lead to the revocation of your driver’s license.


How Long am I Required to Drive with an Ignition Interlock Device After a DWI?

The length of time you must drive with an ignition interlock device installed in your vehicle depends on the suspension period:

  • If your driver’s license was suspended for a year, you would have the device installed for a year;
  • If the length of your license suspension is four years, you will have to drive with the IID for three years; or
  • If your driver’s license was suspended permanently, the ignition interlock device would be installed for seven years.

If you have been charged with driving while impaired, do not hesitate to contact a Charlotte criminal defense attorney to avoid a DWI conviction and the penalties that come with it. Get a phone or video consultation by calling at (704) 370-2828 to speak with our detail-oriented and well-versed lawyers with offices in Charlotte, Lake Norman, and Monroe, please contact Arnold & Smith, PLLC today or find additional resources here.







The criminal defense attorneys at Arnold & Smith, PLLC make it their mission to zealously defend their clients on a wide range of criminal matters at both the state and federal levels. These matters may include any charge from traffic offenses; DWI/DUI; drug charges (from simple possession to possession with intent to distribute and trafficking); gun permit denials; weapons offenses; and property crimes (larceny, breaking and entering, robbery, fraud, embezzlement, white collar offenses); to sexually related offenses (indecent exposure; sexual assault, crimes against nature, removal from sex offender registry); and violent crimes (domestic violence; assault; manslaughter; homicide, murder). Other legal issues that Arnold & Smith, PLLC criminal clients may be facing include restraining orders, restraining order and probation violations, expungements; appeals; and immigration issues related to criminal charges. Our criminal defense attorneys are passionate about ensuring that individuals empower themselves by being informed about their constitutional rights, and stand at the ready to fight in the defense of those facing criminal charges.






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