California ignition interlock device (IID): how long, cost, and the rules

An ignition interlock device (IID) is the piece of a California DUI that most directly decides whether you keep driving. This page is the dedicated IID guide under the suspensions cluster — what the device is, how long you’re required to have one, what it costs, and the exemptions — while the DUI court-track page covers the conviction suspensions and DUI program around it.

One thing up front: this is a plain-English description of the general rules, not legal advice, and it never tells you what to do about your own case. A DUI is active legal jeopardy with fast deadlines. Your DMV order sets your exact terms, and the single most useful steps are to request a DMV hearing within 10 days of your arrest and talk to a DUI attorney.

What an ignition interlock device is

An IID is a small breath-alcohol analyzer wired to your vehicle’s ignition. You blow into it before the engine will start; if it detects alcohol above a set limit, the car won’t start. As you drive, it asks for random “rolling” retests so the driver can’t have someone else start the car. The device logs every result and has to be recalibrated and inspected at least every 60 days by your provider, who reports to the DMV. Only state-approved manufacturers may install one.

Why installing early keeps you driving

The reason to act early is simple: under SB 1046 — the statewide law in effect since January 1, 2019 — installing an IID lets you drive on a restricted license instead of sitting out a hard suspension. Rather than waiting out a “no driving” period, you install the device, put an SR-22 on file, enroll in your DUI program, and drive under the IID restriction. For many people that is the difference between keeping a job and not, which is why the device is usually installed as soon as the order allows.

How long you need one

The mandatory period scales with your priors (Vehicle Code §23575.3):

• First DUI with injury (§23153): 6 months
• Second DUI: 12 months
• Third DUI: 24 months
• Fourth or more: 36 months

That top figure is a hard ceiling — three years. Vehicle Code §23575 states the restriction runs “not to exceed three years from the date of conviction.” You may see a “one to four years” phrasing on the DMV’s own summary page and “48 months” or “4 years” figures elsewhere — treat those as loose or incorrect for a DUI conviction. Use the per-offense schedule above, and remember your DMV order is the final word on the exact term for your case. If it’s unclear, confirm with the DMV Mandatory Actions Unit (below).

A first DUI: your two options

A first DUI without injury is not required to install an IID. Instead you choose:

• Install an IID — full driving privileges (drive anywhere), for about 6 months, or
• A 1-year restricted license — no IID, but you may only drive to and from work and your DUI program.

Most people who need to drive normally choose the IID. A first DUI with injury doesn’t get this choice — the 6-month IID is mandatory.

The DMV track and the court track

A DUI runs on two separate tracks, and the IID sits across both:

• The DMV / administrative track — the Administrative Per Se (APS) suspension the DMV starts from the arrest itself.
• The court / conviction track — the suspension a court imposes if you’re convicted, covered on the DUI court-track page.

They run in parallel. Two consequences matter here: a chemical-test refusal and under-21 drivers are not eligible for the optional IID-restricted license, and beating or reducing the criminal case does not by itself clear the APS action. Deal with each track on its own.

What it costs

The cost is set by private, state-approved providers, so it comes as a range — shop them and confirm current pricing. Income-based assistance is required for lower-income drivers.

(See the cost table above.) If your household income is at or below 100% of the federal poverty level, providers must reduce the total to as little as 10% of cost. The DMV’s own restriction and administrative fees are billed separately on your order.

When you cannot install one: exemptions

You can request an exemption from installing — but read the catch first: an exemption does not shorten your suspension or lift the restriction. You still serve the full suspension, and the IID requirement attaches to any vehicle you drive once you’re eligible again. File form DL 4062 within 30 days of your Order of Suspension/Revocation if you:

• Do not own or have access to a vehicle — declared under penalty of perjury (you’re not eligible if you own a vehicle that simply doesn’t run or is on planned non-operation),
• Have a qualifying medical condition that prevents you from providing a breath sample, or
• Live out of state.

A few more limits: to drive an employer’s vehicle for work you file the employer-notification form (DL 923) — but not if you took a non-ownership exemption. Commercial drivers cannot substitute an IID for the suspension, and you cannot operate a motorcycle during the IID restriction.

Wet reckless and special cases

A “wet reckless” (a plea to reckless driving involving alcohol, Vehicle Code §23103.5) is not subject to the mandatory statewide IID — but a court may still order an interlock as a condition. Felony DUIs, out-of-state priors, and cases with injury or death carry their own rules that turn on specifics only an attorney should weigh. If that’s your situation, don’t rely on a general guide — get counsel and confirm your terms with the DMV.

Forms and who to contact

• DL 920 — Verification of Installation. Your state-approved IID provider completes and submits this to the DMV once the device is installed; keep your copy.
• DL 4062 — IID Exemption Request (linked above). File within 30 days of your order if you qualify for a non-ownership, medical, or out-of-state exemption.
• DL 923 — Employer Notice, if you’ll drive an employer’s vehicle for work.

For your specific order, term, and reinstatement requirements, the authority is the DMV Mandatory Actions Unit at (916) 657-6525, and the DMV’s IID program page and its exemption-requests page. Once your case resolves, the suspensions guide has the reinstatement steps.