Ignition Interlock FAQ – Frequently Asked Questions

We are often asked similar questions about Ignition Interlock Devices or Car Breathalyzers – how they work, how much they cost, how effective they are etc – so we’ve gathered together some of the more typical enquires which you may find useful in deciding what is the best for you!

What is an ignition interlock?
An ignition interlock is a breath analyzer installed into a vehicle to prevent a person from starting the engine after consuming alcohol. If your breath alcohol content (BAC) is over the authorized limit, the vehicle will not start

How does an ignition interlock work?
The driver must exhale into the device before the vehicle is started. If the BAC analyzed result is greater than the programmed BAC, the device will prevent the engine from starting.

Why would I have an ignition interlock installed in my vehicle?
If your license was suspended because of a DUI/DWI offense, the court may require you to get an ignition interlock device to fully restore your driving privileges.

What happens if an offender does not get an ignition interlock installed?
Failure to have an ignition interlock installed when ordered by a judge could result in an additional driving privilege suspension.

How reliable are ignition interlocks?
Alcohol ignition interlocks are required to meet standards established by the National Highway Traffic Safety Administration (NHTSA). The NHTSA standards ensure the device is reliable and are tested by independent laboratories.

Are ignition interlocks effective?
The ignition interlock is the most effective tool for combating alcohol impaired driving. Many DUI/DWI offenders choose to drive illegally with a suspended or revoked license. The ignition interlock provides a control mechanism to keep drivers from driving intoxicated. With the use of interlocks more lives will be saved, serious injuries can be greatly reduced, and roadways will be safer.

According to MADD, studies have shown that the devices are up to 90 percent effective in keeping convicted drunk drivers from recommitting the crime, as long as installed on the vehicle. Decreasing recidivism, the re-arrest of an offender who has completed the interlock program and regained unrestricted driving privileges, is a primary goal of the interlock program.

How much does ignition interlock cost?
The costs of interlocks varies but are about $70-$150 to install and about $60-90 dollars per month for monitoring and calibration.

Will my car be damaged when the ignition interlock is installed?
No, ignition interlocks are connected to the wiring of the vehicle under the dash and hood. At the end of the program, the wiring is returned to its original condition.

Are there ways to bypass the device, like having someone else take the breath test for me (i.e. curb service)?
Yes, however that person or another sober individual must ride in the vehicle because the unit will randomly ask for “running retests.” If the test is not taken or is failed, the unit will log a RETEST VIOLATION and the alarm horn will honk until the vehicle is turned off. Most states have laws that include fines and jail for individuals assisting in the circumvention of an interlock.

What is the penalty for having someone else take the breath test for me?
Starting the car in some way other than blowing into the device, is an additional suspension of driving privileges.

Can someone use a balloon or other air source to mimic human breath?
No, current devices have technology such as voice-tone monitoring or temperature gauges which cause the interlock to abort artificial breath samples.

What happens if participant fails the breath test?
The interlock will enter a temporary lock out period of a few minutes for the first failed BAC test and a longer lock out for any subsequent failed BAC tests. This permits an opportunity for the alcohol to dissipate from the mouth and for the participant to consider the reason for the failed BAC test.

Will using medicine or mouthwash affect the breath test?
Yes, mouthwash or other common substances that contain alcohol will affect the test. Allow sufficient time for the alcohol to dissipate from your mouth to avoid a FAIL test result.

If the device malfunctions, will it shut off the vehicle?
No, the device has no means of interrupting operation of the vehicle once it is started.

Can a participant leave his car running outside a bar, drink inside and then drive away?
No, the device will randomly ask for breath tests while the vehicle is running. If a sample is not given when requested the device logs a RETEST VIOLATION and the alarm horn starts to honk until the vehicle is shut off.

Is it dangerous to provide a “running retest”?
No, the participant has several minutes to provide the sample or pull over to the side of the road and a safe area to provide the breath sample. There are no buttons to push; the only requirement is to breath into the device to complete a breath sample.

How often does the interlock need service?
Typically every 30-60 days, possibly more frequently if there are violations.

Can other people beside the participant drive the interlock equipped vehicle?
Yes, anyone driving the vehicle must use the interlock and is responsible for any violations. All other drivers should be trained on the operation of the device.

What is the offender has more than one vehicle?
The driver under this law can not drive any vehicle that does not have an ignition interlock installed. The DMV imprints a notation on the driver’s license stating that the person shall not operate a motor vehicle unless it is equipped with an interlock device and enters this requirement in the person’s driving record.

Is the device required for DUI/DWI offenders in all states?
Almost all 50 states have laws permitting the imposition of ignition interlock devices as sentencing alternatives for drunk drivers. Most states now permit judges to order the installation of an ignition interlock as a condition of probation for repeat offenders; and some states mandate installation for first time offenders.