For a lot of people, the ignition interlock device is the part of a DUI that lingers the longest. The court date passes, the fines get paid, the classes end, and you are still blowing into a little machine bolted under your dashboard every time you want to drive to work. It is inconvenient, it is a daily reminder, and it costs money month after month.

I want to give you a straight explanation of how ignition interlock devices work in California. When you have to install one, what it costs, how long it stays, and how you finally get it removed. Understanding the rules up front takes some of the mystery out of it and helps you plan.

What an Ignition Interlock Device Actually Is

An ignition interlock device, or IID, is a breath-testing unit wired into your vehicle's ignition. Before the car will start, you have to blow into it. If it detects alcohol above a low preset level, the car will not start. While you are driving, it will also prompt you for "rolling retests" at random intervals, and you blow into it again to confirm you are still sober. The device logs every test.

A state-certified installer puts the device in, and you have to bring the car back periodically, usually about every 60 days, so the installer can calibrate the unit and download the data log. That data goes to the DMV and, where relevant, the court. Missed tests, failed tests, and tampering all show up in the log, and any of those can create problems for you.

The IID is not meant to be a punishment so much as a control. It exists to let you keep driving while giving the state confidence that you are not driving after drinking. For most people it is the price of staying on the road during and after a DUI case.

When California Requires an IID

California's rules on ignition interlock devices changed meaningfully a few years back, and the current framework gives many DUI drivers a choice they did not used to have. Here is the general picture, though the specifics always depend on your history and the facts of your case.

First-offense DUI with no injury

For a first DUI that did not involve injury, you generally have two options. You can serve a period of hard license suspension where you cannot drive at all, or you can install an IID and get a driving privilege that lets you drive without the usual restrictions during that time. Many people choose the IID route because it lets them keep driving to work, to school, and to their DUI classes. When an IID is installed voluntarily on a first offense, the required term is often around six months, though the exact length depends on your case.

Repeat offenses and DUIs involving injury

For second and subsequent DUI convictions, and for DUIs involving injury under Vehicle Code 23153, an IID is typically mandatory, and the required term gets longer as the offenses stack up. A second offense commonly requires the device for a year, a third for two years, and a fourth or an injury case for longer still. The idea is that the more serious or repeated the conduct, the longer the state wants the control in place. Our pages on the second DUI and third DUI go into how penalties escalate across offenses.

Refusals and other situations

If you refused a chemical test, or if the DMV suspends your license through the Administrative Per Se process, an IID can come into play as a condition of getting a restricted or reinstated license. The interplay between the court order and the DMV requirement is one of the more confusing parts of this, which is exactly the kind of thing an attorney can map out for your specific situation.

What an IID Costs

There is no single price, because the device is provided by private state-certified companies and the cost varies by provider and by your vehicle. As a general range, you should expect an installation fee, often somewhere in the range of about 70 to 150 dollars, plus a monthly leasing and calibration fee that commonly runs somewhere around 60 to 100 dollars per month for the length of your term.

Add it up over six months to a year or more and the IID becomes one of the more expensive ongoing pieces of a DUI. On top of the device itself, a DUI usually brings an SR-22 insurance filing and higher premiums, so the real cost of driving after a DUI goes well beyond the fine on the court paperwork.

California does have an income-based fee reduction program for the ignition interlock device. If your income is low enough, certified providers are required to reduce the installation and monthly costs on a sliding scale. If money is tight, ask your provider about the reduced-cost program, because a lot of people who qualify never find out it exists.

Living With the Device

A few practical things people wish they had known:

  • Only you should blow into it. Do not have someone else provide a sample to start your car. That is a form of tampering and it can violate the terms of your restricted license.
  • Certain foods, mouthwash, and other products contain alcohol that can register on the device. Rinse your mouth with water and give it a few minutes before you blow if you are worried about a false reading.
  • Keep every calibration appointment. A missed calibration can lock the device and can be reported as a violation.
  • The device logs everything. If the log shows failed tests or tampering, it can extend your IID term or create fresh problems with the court and the DMV.

None of this is meant to scare you. Millions of people have driven with an IID and gotten through it. But treating the device casually is where people get into trouble, and a violation can reset the clock you are trying to run out.

How to Get the IID Removed

The device does not come off just because the calendar says your term is up. Removal is a process, and you have to get it right or you can end up paying for extra months.

In general, the steps look like this. You complete your required IID term. You make sure the DMV shows you as eligible, which usually means the device has been in place for the full required period with a clean recent log and no unresolved violations. The DMV then authorizes removal. Only after you have that authorization do you take the vehicle to a certified installer to have the device removed. Pulling the device early or without authorization can be treated as noncompliance and can extend your requirement.

A clean record on the device near the end of your term matters. If your recent data log shows failed tests or lockouts, the DMV can require more time before it will let you remove the unit. So the last stretch before removal is not the time to get careless.

Because the IID sits at the intersection of the court order and the DMV, it is easy to lose track of exactly when and how you are eligible to remove it. If you are unsure where you stand, that is worth a phone call. You can also read our Ignition Interlock Devices practice area and our page on License Suspension for more on how the driving-privilege side fits together.

The Bigger Picture: Avoiding or Reducing the Requirement

The surest way to shorten your time with an ignition interlock device is to fight the underlying case. A reduction to a wet reckless, a dismissal, or a favorable resolution can change or eliminate the IID requirement entirely. The device is a consequence of the conviction, so the conviction is where the real leverage is.

That is why I tell people not to think about the IID in isolation. It is one piece of a case that includes the criminal charges, the DMV action, your license, and your insurance. Handle the case well and the IID often takes care of itself. Every situation is different, and this article is general information, not legal advice about your case.

If you are staring down an ignition interlock requirement, or you are earlier in the process and want to keep it from happening at all, the time to act is now. The choices you make in the first days after an arrest ripple through everything that follows, including how long you might live with a device in your car.

At Crudo Law, you deal directly with Joe Crudo, and consultations are free and confidential. Call (858) 622-7280 or visit our contact page to talk through your DUI, your license, and what an ignition interlock device would mean for you.