What is Interlock?

If you have recently been charged with Driving While Intoxicated-DWI, a Charlotte DWI Lawyer can assist in obtaining a license for the year following your potential conviction. If you have blown a.15 or more on the Intoxilizer, or been convicted in any state, not just a DWI in North Carolina of a DWI within seven years of the current offense, you may be required to install and Interlock device within you automobile.Due to the numerous extent of factors to consider, it is imperative that an individual contacts a Charlotte DWI Lawyer to guarantee proper representation during a sentencing hearing to decide if you must engage in an interlock system.

What an ignition interlock is, and who orders one in North Carolina

An ignition interlock is a breath-testing device wired into a vehicle’s ignition, so that the vehicle will not start until the driver provides a sample below a set alcohol concentration. In North Carolina the device must be of a type approved by the Commissioner of Motor Vehicles, and it is installed by an approved vendor rather than by the driver.

Two different bodies can require one, at two different stages, and the statutes differ in whether they leave the decision-maker any choice. A judge may include an interlock restriction in a limited driving privilege under G.S. 20-179.3(g3), and must include one under G.S. 20-179.3(g5) where the license was revoked for a conviction under G.S. 20-138.1 and “the person had an alcohol concentration of 0.15 or more”. Separately, the Division of Motor Vehicles imposes interlock as a condition of the license itself once the license is restored, under G.S. 20-17.8. The two are separate orders with separate paperwork, and it is common for both to apply to the same person in sequence.

The convictions that trigger interlock on restoration

Interlock is not a consequence of every impaired driving conviction in North Carolina. G.S. 20-17.8 attaches the requirement to defined categories of revocation, and a driver outside those categories is restored without it.

A revocation for a conviction under G.S. 20-138.1 where “the person had an alcohol concentration of 0.15 or more”
A revocation for a conviction under G.S. 20-138.1 where the person has been convicted of another offense involving impaired driving that occurred within seven years
A revocation for a conviction under G.S. 20-138.1 where the person was sentenced under G.S. 20-179(f3), which is Aggravated Level One punishment
A revocation for a conviction of habitual impaired driving under G.S. 20-138.5
For licenses revoked on or after 1 December 2024, a revocation for a conviction of felony death by vehicle or felony serious injury by vehicle under G.S. 20-141.4, including the aggravated and repeat versions of those offenses

How long the requirement lasts

The interlock period under G.S. 20-17.8 is tied to the length of the revocation that preceded it, and it runs from the date the license is restored rather than from the date of conviction. The statute sets one year from the date of restoration where the original revocation period was one year, three years from the date of restoration where the original revocation period was four years, and seven years from the date of restoration where the original revocation was a permanent revocation.

Time already spent driving under a limited driving privilege that carried an interlock restriction is not lost. Where the person “was eligible for and received a limited driving privilege”, G.S. 20-17.8 applies the period for which that privilege was held toward the interlock requirement, so the months spent with the device before restoration shorten the period that follows it.

The restrictions that travel with the device

An interlock requirement in North Carolina is not only an installation requirement; it is a set of driving restrictions attached to the license. G.S. 20-17.8 requires the person to designate, in accordance with the policies of the Division, the registered vehicles they own and operate or intend to operate, to operate “only a vehicle that is equipped with a functioning ignition interlock system”, and to “personally activate the ignition interlock system before driving”.

The device is set low. The statute imposes a restriction that the person not drive “with an alcohol concentration of 0.02 or greater”, a figure a quarter of the 0.08 in G.S. 20-138.1 and low enough that ordinary social drinking will register.

A different statute writes an alcohol concentration restriction onto the restored license itself, and its figure is often not 0.02. Under G.S. 20-19(c3) the first restoration of a license revoked for a conviction of impaired driving under G.S. 20-138.1 carries a restriction against operating a vehicle with an alcohol concentration of 0.04 or more; a second or subsequent restoration carries a 0.00 restriction, as does a restoration after a conviction under G.S. 20-138.3 by a person under 21; and 0.02 is reserved for a listed group of more serious matters, among them impaired driving in a commercial motor vehicle under G.S. 20-138.2, habitual impaired driving, and felony death or serious injury by vehicle involving impaired driving. That restriction is recorded on the license and governs driving generally rather than only the equipped vehicle. It runs for three years in the ordinary case, for seven years from restoration where the revocation had been permanent, and until the twenty-first birthday for the under-21 group.

On a limited driving privilege, interlock removes the hours and purposes limits

A limited driving privilege under G.S. 20-179.3 is ordinarily a narrow thing. The statute confines driving to essential purposes — employment, the maintenance of the household, education, court-ordered treatment or assessment, community service ordered as a condition of probation, emergency medical care and religious worship — and it confines most of that driving to “standard working hours”, defined as “6:00 A.M. to 8:00 P.M. on Monday through Friday”, unless the applicant produces the documentation the statute requires before non-standard hours can be authorized.

Since changes that took effect on 1 June 2022, those limits fall away where interlock is part of the privilege. Both the permissive provision in G.S. 20-179.3(g3) and the mandatory one in G.S. 20-179.3(g5) provide that the limitations in subsections (a), (f), (g), (g1) and (g2) do not apply when the person is operating the designated motor vehicle with a functioning ignition interlock system. A person holding such a privilege may drive the designated equipped vehicle at any hour of the day and for any purpose. The trade is a real one: the device and its running costs, in exchange for driving that is not confined to a timetable.

Driving without the device is charged as driving while license revoked

The enforcement provision in North Carolina is severe by design. Under G.S. 20-17.8 a person who drives a vehicle that is not equipped with a functioning ignition interlock system, or who otherwise violates the restrictions, “commits the offense of driving while license revoked for impaired driving” and is punished under G.S. 20-28(a1).

There is an administrative consequence where no such charge is brought, but it is not the same throughout the interlock period. For a violation earlier in the period, the statute directs that a person who is not charged with driving while license revoked “shall have the person’s license revoked by the Division for a period of one year”. For a violation in the final 90 days of the restriction period, a provision added with effect from 1 December 2024 substitutes an extension for that revocation: the interlock restriction continues for a further 90 days, or until the person has been violation-free for a 90-day period.

Who pays, and the affordability waiver

The cost falls on the driver. G.S. 20-179.5, headed “Affordability of ignition interlock system”, provides that “the costs incurred in order to comply with the ignition interlock requirements … shall be paid by the person ordered to install the system”.

The same section creates relief for those who cannot meet it, but the relief has to be applied for rather than assumed. A person may apply where their “income is at or below one hundred fifty percent (150%) of the federal poverty line”, or where they are enrolled in Temporary Assistance for Needy Families, Supplemental Security Income, the Supplemental Nutrition Assistance Program, the Low Income Home Energy Assistance Program or Medicaid. An approved applicant “shall not be required to pay for installation or removal” and receives “a fifty percent (50%) discount on the monthly service rate”.

The medical exception is narrow

North Carolina recognizes that some people cannot physically use the device, but the exception in G.S. 20-17.8 is confined. It is available only to a person subject to the requirement “solely for the reason set forth in subdivision (a)(1)” — that is, solely because the alcohol concentration was 0.15 or more. It is not available where the trigger was a prior impaired driving conviction, Aggravated Level One sentencing, habitual impaired driving, or a conviction of felony death or serious injury by vehicle.

The procedure is medical and the burden sits with the applicant. The person must submit to examination by “two or more physicians or surgeons duly licensed” and provide their certificates, and the Commissioner considers whether the person is incapable of personally activating an ignition interlock system. The statute states in terms that “the burden of proof of such fact is upon the person seeking the exception”. Inconvenience is not the test.

How interlock fits with restoration in Mecklenburg County

Interlock is the last of several conditions rather than the first. A license revoked for impaired driving in North Carolina is not restored until the Division receives the certificate of completion required by G.S. 20-17.6, which follows a substance abuse assessment and then either an alcohol and drug education traffic school or the substance abuse treatment the assessment recommends.

Only once the revocation period has run and that certificate is in hand does the interlock condition under G.S. 20-17.8 attach to the restored license. Installation is arranged with an approved vendor, and the restriction is recorded on the license alongside any alcohol concentration restriction imposed under G.S. 20-19(c3), so both are visible to any officer who stops the vehicle in Charlotte or anywhere else in the State.

Common questions

Is an ignition interlock required after every DWI conviction in North Carolina?

No. G.S. 20-17.8 attaches the requirement to defined categories of revocation: a conviction under G.S. 20-138.1 where the alcohol concentration was 0.15 or more, where the person has a conviction of another offense involving impaired driving that occurred within seven years, or where the person was sentenced under G.S. 20-179(f3); a conviction of habitual impaired driving under G.S. 20-138.5; and, for licenses revoked on or after 1 December 2024, a conviction of felony death or serious injury by vehicle under G.S. 20-141.4.

What alcohol concentration does a North Carolina interlock allow?

The restriction that comes with the device under G.S. 20-17.8 is that the person not drive “with an alcohol concentration of 0.02 or greater”, which is a quarter of the 0.08 in G.S. 20-138.1 and low enough that a small amount of alcohol, or a mouthwash containing alcohol, can register. The restriction written onto the restored license under G.S. 20-19(c3) is a separate figure and often a different one: 0.04 on a first restoration after a conviction under G.S. 20-138.1, 0.00 on a second or subsequent restoration and for a person under 21 convicted under G.S. 20-138.3, and 0.02 for a listed group of more serious offenses such as habitual impaired driving and impaired driving in a commercial motor vehicle.

What happens if someone drives a car without the interlock installed?

Under G.S. 20-17.8 a person who drives a vehicle not equipped with a functioning ignition interlock system, or who otherwise violates the restrictions, “commits the offense of driving while license revoked for impaired driving” and is punished under G.S. 20-28(a1). Where no such charge is brought, a violation earlier in the interlock period leads the Division to revoke the license for one year; a violation in the final 90 days instead extends the interlock restriction by a further 90 days, or until the person has been violation-free for a 90-day period.

Can the cost of an ignition interlock be reduced in North Carolina?

G.S. 20-179.5 puts the cost on the person ordered to install the device, but allows an application for relief where income is “at or below one hundred fifty percent (150%) of the federal poverty line” or the person is enrolled in Temporary Assistance for Needy Families, Supplemental Security Income, the Supplemental Nutrition Assistance Program, the Low Income Home Energy Assistance Program or Medicaid. Relief is not automatic; it follows an approved application, after which the person pays nothing for installation or removal and receives a fifty percent discount on the monthly service rate.

Written for North Carolina law and reviewed by David P. Sheehan, attorney, Charlotte. General information, not legal advice — see the disclaimer.