Interlock Ignition Device (IID)

Interlock Ignition Device (IID) 2017-04-19T20:43:54+00:00

Ignition Interlock Device (IID)

An Interlock Ignition Device (IID) is an electronic device installed in a vehicle to prevent the driver from driving after consuming alcohol. Unlike Oregon’s Intoxilyzer 8000, IIDs are much smaller and driver’s must pay to lease and install them as part of Oregon’s DUI Diversion Program, or after conviction for DUI. Oregon drivers who enter diversion or who have been convicted of DUI must install an Interlock Ignition Device (IID) in any motor vehicle they drive unless they are approved for one of Oregon’s Interlock Ignition Device (IID) exemptions.

These IID devices are essentially small breath testing devices that are physically installed into any vehicle you drive, and they are connected into the ignition system to prevent you from starting the car if you’ve consumed any alcohol. You have to blow approximately 1.5 liters of air and you cannot have more than .025% BAC or the vehicle will not start. Notice that this is more of a “zero tolerance level” (you can’t have any alcohol on your breath) as opposed to the .08% BAC standard commonly used for DUI cases. You not only have to blow into the device to start the car, but approximately 5-10 minutes into the drive, and then 20-40 minutes following while driving the car. If you don’t, the device is designed to flash your lights or honk your horn until a clean breath test is entered into the device. This measure is designed to ensure that a driver doesn’t have someone else start the car for them.

While the Interlock Ignition Device (IID) is touted as being a very effective solution to drunk driving, there are a few problems with the devices. First, they are expensive. At around $75 per month and with other installation, calibration fees, and then removal, many people have trouble affording them– especially if they have more than one car or truck they occasionally drive. Second, they are distracting because the driver must blow into the device at random times while driving. Third, they can be a significant inconvenience when installed in shared vehicles (cars used by families, car pools, etc). Fourth, they can have technical problems. While they generally work as designed, some drivers have trouble blowing hard-enough to activate the device. The devices can also have false positives and fail to start.

More information on when Oregon Interlock Ignition Devices (IIDs) are required can be found at the Oregon DMV Suspensions & Revocations page. The page also features a list of approved Interlock Ignition Devices in Oregon.

Frequently Asked Questions About the Interlock Ignition Device (IID)

What does an Ignition Interlock Device cost?

The rental of an IID typically runs about $70-75 per month to rent or lease. There are also fees incurred for installing, uninstalling, and calibrating the units.

Can I buy an Ignition Interlock Device?

For drivers that must install an IID for a year or longer, it would seem to be be less expensive to buy a unit outright rather than to rent it each month. Unfortunately, the manufacturers will not sell the devices to consumers and they must instead be rented or leased through IID installers.

How accurate is the Ignition Interlock Device?

Accurate-enough to detect the presence of alcohol. While the devices are not admissible in Oregon courts as to a specific BAC, they are certified to meet NTHSA specifications for accuracy for IID purposes.

Will the Interlock Ignition Device drain my battery to where I cannot start my car?

No. The devices draw minimal power.

Will bad breath cause my Interlock Ignition Device to fail?


Will drinking fruit juice cause my Interlock Ignition Device to fail?

No, unless the fruit juice is quite old and has actually fermented (thus producing some alcohol). It’s unlikely that you’d consume fruit juice this old as the decay would not be palatable.

Will eating spicy foods cause my Interlock Ignition Device to fail?


Will using mouthwash cause my Interlock Ignition Device to fail?

Yes, if the mouthwash you use contains alcohol, and if you do not wait approximately 15 minutes for the residual alcohol on your breath to evaporate prior to blowing into the IID.

Will using hair spray, after-shave, perfume, or cologne cause my Interlock Ignition Device to fail?

Possibly, if the products you’re using contain alcohol and if they have not evaporated prior to you using the IID. Wait several minutes after applying these products before using the IID. Alcohol evaporates long-before the scent of these products so 10-15 minutes should be sufficient.

Will chewing gum my Interlock Ignition Device to fail?

Not unless the chewing gum contains alcohol. Some chewing gums do contain alcohol sugars and essential oils that are very similar to alcohol in molecular structure. Do not blow into the IDD with anything in your mouth, and– ideally– wait 15 minutes after drinking, eating, or chewing before providing an IID sample.

Will using breath mints cause my Interlock Ignition Device to fail?

Not unless the breath mints contains alcohol. Some breath mints do contain alcohol sugars and essential oils that are very similar to alcohol in molecular structure. Do not blow into the IDD with anything in your mouth, and– ideally– wait 15 minutes after drinking, eating, or chewing before providing an IID sample.

Will smoking cigarettes cause my Interlock Ignition Device to fail?

No, but you should not blow smoke into the IID because it could damage the machine.

Will chewing tobacco cause my Interlock Ignition Device to fail?

Not unless the chew contains alcohol. Do not blow into the IDD with anything in your mouth, and– ideally– wait 15 minutes after drinking, eating, or chewing before providing an IID sample.

Can I have someone else blow into the Interlock Ignition Device in order to start my car?

No. Not only would that be unlawful, but the new IIDs take a photograph of the person providing a breath sample.

Will the Interlock Ignition Device kill the engine if I fail a test or don’t provide a sample while driving? Isn’t that dangerous?

The IID will not allow you to start your car if there’s alcohol on your breath. If– while driving– you have alcohol on your breath or fail to provide a sample, the IID will record a violation and may flash your lights or sound your horn. However, it will not turn your car off while driving.

Can I start my car with an Interlock Ignition Device if I only had one drink (a beer, glass of wine, one cocktail, or a shot of hard liquor)?

This question raises many complicated issues. If you are on diversion or probation, consuming any alcohol could result in termination of your diversion, a probation violation, or revocation of your probation– regardless of whether you drive or not. If you are required to have an IID in your car, it means you recently had a DUI. Which raises the question, “Why are you drinking at all?” From a strictly scientific standpoint– setting aside legal issues and moral issues– whether or not a single drink will cause an IID fail has to do with: (1) your size and weight, (2) whether the drink was consumed before, with, or after food, (3) the size of the drink, (4) the alcohol content of the drink, and (5) the amount of time that has elapsed since you finished the drink and are blowing into the IID. For a more in-depth discussion of this topic, please refer to our page on the “legal limit” in Oregon.

Do I have to install an Interlock Ignition Device in all my vehicles?

No, only the vehicles you’ll be driving. If– for example– you have a truck, RV, motorcycle, and a passenger car, it may be smart to only install the IID in the passenger car during the time that an IID is required. This will save you money, rather than installing IIDs in multiple vehicles.

What if I want to rent a car? Will I still need an Interlock Ignition Device?

Most people who are required to have an IID do not rent or borrow any vehicles during the period where the IID is required because it’s not practical or economical to install an IID in a vehicle for a short period of time. However, if a short-term vehicle was absolutely needed, an IID could be installed (provided that the company renting or loaning the vehicle was okay with the IID being installed).

What if my wife, husband, girlfriend, boyfriend, child, or friend drives my car? Is there a bypass for the Interlock Ignition Device?

Unfortunately there isn’t. You will therefore want to be thoughtful as to which vehicle you are going to drive with the IID because anyone who drives that vehicle cannot consume alcohol beforehand, and they must go through the IID testing procedures before starting the vehicle and while driving.

Where can I find a place to have my Interlock Ignition Device installed?

For a list of Oregon IID installers, please see our list of Interlock Ignition Device installers.