When is an ignition interlock required after a Florida DUI, and for how long?

An ignition interlock device is a breath tester wired to the vehicle. Under section 316.1937(1), Florida Statutes, it is installed so that the vehicle will not start if the driver's blood alcohol level is in excess of 0.025 percent, or another level the court specifies. The interlock rules sit in three places: the DUI sentencing statute (s. 316.193), the court's interlock statute (s. 316.1937), and the licensing statute that FLHSMV applies before it issues a license (s. 322.2715). This page brings them together. For the fines, jail and revocation that come with each conviction, see our table of Florida DUI penalties; for Mr. Mead's approach to the charge itself, the main DUI defense page.

How does an interlock order work, step by step?

1. Sentencing. At a DUI conviction the judge orders the interlock and its period where the statute requires it, or where the court chooses to for an ordinary first conviction.
2. The court reports it. FLHSMV says most courts report DUI convictions to it electronically, and that the order should reflect both the suspension period and the interlock requirement.
3. Installation. When the driver becomes eligible for a permanent or restricted license, the device is installed by one of the FLHSMV-approved providers on every vehicle the driver owns or leases and routinely drives.
4. The "P" restriction. FLHSMV issues the license with a "P" restriction, and the interlock period starts that day.
5. Living with the device. The vehicle will not start if the driver's level is above 0.025 percent, or the level the court specifies (s. 316.1937(1)).
6. The full period. The device stays on for the whole required period; tampering or getting around it can bring a new revocation, as described below.

Which DUI convictions require an interlock, and for how long?

FLHSMV's Ignition Interlock Program page summarizes the same rules in a chart and lists the first conviction at an ordinary level as "If court ordered." For a fourth or later conviction it describes the 5 years as a condition of a hardship license. Out-of-state DUI convictions count as convictions for these periods (s. 322.2715(2)).

A 0.15 reading matters twice over: it is what moves a first conviction from an optional interlock to a mandatory one. That is one reason the breath or blood result, and how it was obtained, gets close attention in a DUI defense.

Which vehicles need the device, and when does the clock start?

The interlock goes on "all vehicles that are individually or jointly leased or owned and routinely operated by the convicted person," and it applies when the person qualifies for a permanent or restricted license (s. 316.193(2)(a)3.; s. 322.2715(1)). FLHSMV says that if the person is otherwise eligible, the license is issued with a "P" restriction showing that an interlock is required, and the required period begins on the day the "P" restriction is issued. Devices must be approved under section 316.1938, and FLHSMV publishes the list of approved service providers and device models on its Ignition Interlock Program page.

If the court does not order a mandatory interlock, or orders it for less than the required period, at sentencing or within 30 days, the statute tells FLHSMV to require the device anyway before reinstating the license (s. 322.2715(4)). A documented medical condition that would keep the device from working can be considered, but a driver granted a medical waiver must wait out the interlock period before getting a restricted license, or must hold an employment-purposes-only license under DUI program supervision until it ends (s. 322.2715(1)).

Who pays for the interlock?

The driver. Section 316.193 places the device "at the convicted person's sole expense." On top of the provider's installation and maintenance charges, the installer collects and sends $12 to FLHSMV for each installation (s. 322.2715(5)). If the court finds the person unable to pay for installation, it may order that part of the DUI fine be used to cover that cost (s. 316.1937(2)(d)). FLHSMV's page also notes that the approved vendors began offering discounts in 2020, with criteria set by each vendor. The wider costs of a DUI are listed in how much a DUI costs in Florida beyond the fine.

Does a hardship license come with an interlock?

Often. FLHSMV says the interlock is also required when a driver convicted of DUI applies for a restricted license for work or business purposes, and section 322.271(2)(e) lets the department require one as a condition of reinstatement. Waiting periods and the application itself are covered on our page about a hardship license after a Florida DUI.

Can I drive a company vehicle without an interlock?

In some cases. If a person must drive in the course of employment and the vehicle is owned or leased by the employer, the person may drive that vehicle without an interlock once the employer has been notified of the restriction, and proof of that notice must be kept in the vehicle. The exemption does not apply when the business that owns the vehicle is owned or controlled by the restricted driver (s. 316.1937(7)).

What happens if someone tampers with the device?

Section 316.1937(6) makes it unlawful to tamper with or get around a court-ordered interlock, to ask someone else to blow into it or start the car for the restricted driver, to do that for the restricted driver, or to knowingly lend or lease the driver a vehicle without a working, certified device. A conviction for one of these violations leads FLHSMV to revoke the driving privilege for 1 year, and a separate violation during the same interlock period leads to a 5-year revocation (s. 316.1937(5)(a)). The violation is also a noncriminal traffic infraction (s. 316.1937(8)).

Can an interlock come up before any conviction?

Yes, in two ways. First, a court that orders a vehicle impounded or immobilized after a DUI conviction may dismiss that order if the defendant proves a functioning, certified interlock is installed on all vehicles he or she routinely drives (s. 316.193(6)(i)). Second, the Palm Beach County State Attorney's first-time DUI program lists, among four pre-conditions to be completed within two months, "Proof of successful installation of the Ignition Interlock alcohol monitoring device." Its probation terms then call for "Ignition Interlock Alcohol Monitoring for a period of three (3) months" for readings below 0.150, and "for a period of six (6) months" for readings between 0.150 and 0.200. The program sheet also says eligibility "is determined at the sole discretion of the D.U.I. filing unit," so admission is never automatic. Our page on the Palm Beach County first-time DUI program covers the rest of its terms.

What changes the answer?

• The alcohol reading. A first conviction at 0.08 to 0.149 leaves the interlock to the court; at 0.15 or higher it is mandatory (s. 316.193(2)(c), (4)(c)). How the reading was produced is covered on our page about Florida's breath test rules.
• A passenger under 18. It has the same effect as a 0.15 reading on the interlock (s. 316.193(4)).
• The number of prior DUI convictions. Each prior conviction, including one from another state, lengthens the minimum (s. 322.2715(2), (3)). Repeat cases are discussed on our repeat DUI offenses page.
• How the case ends. The statutory periods follow a DUI conviction. A program or a plea to another charge may carry its own monitoring terms, such as the Palm Beach program's 3 or 6 months described below.
• A medical condition. A documented condition that would prevent the device from working can be considered, with the limits in section 322.2715(1).
• Employment driving. An employer-owned vehicle can be exempt under section 316.1937(7), unless the driver owns or controls the business.

A worked example

For example, take a hypothetical first DUI conviction in Broward County where the breath reading was 0.16 and no minor was in the car. Because the reading was 0.15 or higher, the interlock is mandatory for at least 6 continuous months. If the driver later qualifies for a business-purposes license during the revocation, the device goes on every vehicle the driver owns or leases and routinely drives, at the driver's expense plus the $12 installation charge collected for FLHSMV, and the 6 months start on the day the "P" restriction is issued. If the same driver had blown 0.12 instead, the court could still order an interlock, but would not have to. And if the driver had a DUI conviction in another state 3 years earlier, the Florida conviction would count as a second, with at least 2 continuous years at 0.15 or higher. This is a hypothetical example, not a prediction.

Common mistakes people make

• Assuming the period starts at sentencing; FLHSMV says it starts when the "P" restriction is issued.
• Installing the device on one car while routinely driving another owned or leased vehicle.
• Letting a friend or relative blow into the device, which is unlawful for both people under section 316.1937(6).
• Not checking that the court's electronic report to FLHSMV includes the interlock requirement, as FLHSMV advises.
• Not telling the court about inability to pay, when the statute lets part of the fine go toward installation.
• Driving an employer's vehicle without first notifying the employer and keeping proof in the vehicle.

What to do this week

1. Find the breath or blood result and note whether anyone under 18 was in the car.
2. List every vehicle you own or lease and routinely drive.
3. Gather the dates of any earlier DUI convictions, in Florida or elsewhere.
4. If you drive an employer's vehicle for work, find out who owns or leases it.
5. Handle the 10-day license deadline first; see how to keep your license within 10 days of a Florida DUI arrest.
6. Speak with a lawyer about the test result before any plea is discussed.

Frequently asked questions

Is an interlock required for a first DUI in Florida?

Only if the court orders it, unless the level was 0.15 or higher or a passenger under 18 was in the car; then at least 6 continuous months are mandatory (s. 316.193(2)(c), (4)(c)).

Who installs the device?

One of the providers FLHSMV approves. Its Ignition Interlock Program page lists seven contracted providers and their approved device models.

Can the interlock replace the impound of my car?

The court may dismiss an impound or immobilization order if a working, certified interlock is installed on all vehicles the defendant routinely drives (s. 316.193(6)(i)). The impound rules are on our page about what happens to your car after a Florida DUI.

Does a hardship license require an interlock?

FLHSMV says the interlock is required when a driver convicted of DUI applies for a restricted license for work or business purposes, and section 322.271(2)(e) allows the department to make it a condition.

What happens if the device records a violation?

Tampering, getting someone else to blow, or driving a vehicle without a working device can lead to a 1-year revocation, and 5 years for a separate violation in the same period (s. 316.1937(5)(a), (6)).

Do I still need the higher insurance limits?

Yes. The interlock and the insurance requirement are separate; the insurance rule is explained on our page about FR-44 insurance after a Florida DUI.

How can Mr. Mead help?

Whether an interlock is optional or mandatory, and for how long, depends on the conviction, if there is one, and on the alcohol reading behind it. Mr. Mead looks at the testing and the record from the start, and explains what an interlock order would mean for your work and your family's vehicles. Every case is different, and no outcome can be promised. For a confidential conversation, call (561) 362-6677, 24 hours a day.

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