Do ignition locks stop drunk drivers?

Do ignition locks stop drunk drivers?

By Oregon Anti-Crime Alliance

This is the fourth letter in our series of letters providing information and analysis on important public safety topics that will undoubtedly be discussed during the next legislative session. This letter was sent to all members of the 2011 Oregon Legislative Assembly, on December 27, 2010.

The topic for this letter is saving lives and reducing serious injuries through Ignition Interlock technology and laws.


According to the August 2010 National Highway Traffic Safety Administration (NHTSA) Traffic Safety Facts Report, there were 10,839 alcohol-impaired driving fatalities in the United States in 2009. 115 of these fatalities were on Oregon roads. Although precise injury statistics are not kept for Oregon, we know there were thousands of Oregonians seriously injured in alcohol-impaired driving crashes last year. And, “according to a NHTSA study based on 2006 Centers for Disease Control (CDC) data, motor vehicle crashes are the leading cause of death for those between the ages of 3 and 34.”

While the above paragraph uses numbers to explain the magnitude of the tragedy caused by drunken driving, it does not begin to help the reader feel the survivors’ emotional trauma that lasts for years or even a lifetime. Doug Harcleroad, one of the authors of this letter, went to drunken driving crash scenes when he was Lane County’s District Attorney and has the tragedy and heartache etched in his memory forever. Ask any experienced law enforcement officer in your jurisdiction, and they will tell you about one tragedy after another caused by drunken drivers in your own jurisdiction.


Fortunately, Mothers Against Drunk Driving (MADD) has taught us, as a society, that it’s not OK to drink and drive. And yet, about 25,000 drivers in Oregon were arrested for intoxicated driving last year. Once a person has been caught driving intoxicated, we need to do all we can to keep them from driving intoxicated again. The traditional approach is to suspend their license for a few months to a few years, or forever, if they are a habitual offender. Unfortunately, studies show that 50 to 70 percent of suspended drivers drive anyway! The sanction of suspension doesn’t work over half of the time. We need to do more!


(The following information is taken from MADD publications)

The main reason people drive drunk today is because they can. Technology currently exists that has the potential to eliminate repeat drunken driving offenses – the ignition interlock.

Blow Before They Go

An ignition interlock is a device about the size of a cell phone. It is wired into the ignition system of a vehicle. A convicted drunk driver must blow in to the device in order to start their vehicle. If they have a measurable amount of alcohol in their system, the vehicle will not start. It is a simple and economical way to make sure that offenders can drive to and from work, but that they can’t drive drunk.

How reliable are ignition interlocks?

Alcohol ignition interlocks are required to meet standards set by the National Highway Traffic Safety Administration (NHTSA). These standards ensure that the devices are reliable.

Who pays for the device?

Offenders pay for the interlocks, as they are the ones getting the benefit from it (the ability to drive legally).

How much do the devices cost? What if the offender can’t afford it?

On average, interlocks are about $70-150 to install and about $60-80 per month for monitoring and calibration. This is less than three dollars a day. In most states, interlock companies provide interlock devices for offenders who can’t afford the devices or an indigent fund is set up by the state to cover costs for these offenders.

Are there ways to bypass the device, like having someone else blow into it?

This is possible, and there should be strict penalties for blowing into someone else’s ignition interlock or for having someone else blow into the device. However, interlocks are required to have anti-circumvention features that prevent such activity. One of these features is the running retest, which requires offenders to blow into the device at random intervals once the vehicle has been allowed to start. Furthermore, blowing into an interlock is a learned skill that requires specific training that would most likely be difficult for an impaired person to administer. There are also tamper-proof seals on interlocks. You can learn more about how interlocks work here.

What if someone else drives the vehicle with the interlock and fails a retest?

This is possible. However, when someone commits a crime, he/she is responsible for the consequences of his/her actions. If an interlock is one of these consequences, then the offender is responsible for making sure those driving his/her vehicle do not drive intoxicated. State laws should also have provisions for an appeals process in which offenders can appeal failed tests.

Couldn’t someone just use compressed air to blow into the device?

No, the devices have temperature and air gauges to make sure this cannot occur.

Don’t offenders go back to their old behavior after the device is removed?

Studies have shown that interlock devices decrease recidivism by about two-thirds while installed on the vehicle. When removed, these rates tend to go back to normal. This might not be the case if interlock programs were coupled with treatment and offenders were not allowed to have the device removed until they demonstrated a period of compliance. The possibility of reoffending is much greater if tests are failed during the interlock period. Unfortunately in most states, offenders still automatically get the device removed at the end of the specified period, even if they failed a test the day before. To make laws more effective, states should add provisions for treatment and extended periods for non-compliance.

Could an interlock stop a person’s car in traffic, making a more dangerous hazard?

Interlocks are hooked up to a vehicle’s starter system, not to the engine itself. The interlock does not have the ability to stop the vehicle once it is running for safety reasons. When a driver fails a running retest, the vehicle’s horn will honk and/or the lights will flash to alert law enforcement – the vehicle will not stop.

Is it dangerous to provide a running retest?

The tests are not designed to be done while the car is actually rolling. Interlocks give people a few minutes – enough time to pull over – to perform the retest.

Are ignition interlocks constitutional?

Courts throughout the states have analyzed this issue and no state appellate court has overturned an interlock statute.

Aren’t interlocks an inconvenience to family members who share the offender’s vehicle?

No, they can drive the vehicle as well; they simply must blow into the device and prove sobriety before the car will start. Having an interlock installed on an offender’s vehicle actually allows the offender and his or her family to continue to drive legally. Other sanctions like vehicle impoundment or immobilization do not allow for this.

What if someone’s health inhibits them from providing a sufficient breath sample?

Individuals with low lung capacities due to being ill, having asthma or pulmonary disorders are generally able to provide the needed breath sample. If they can demonstrate that they are unable, the device settings can be adjusted to account for this. Failing that, medical waivers are needed.

Won’t offenders just re-title their cars or sell them to avoid having to install an interlock?

They can and do. It is imperative that state laws plan for this by requiring that all cars that the offender operates, not just owns, are equipped with an interlock. Also, offenders choosing not to drive should be required to have some other form of electronic monitoring, like continuous alcohol-sensing ankle bracelets. In Hancock County, Indiana, alcohol ignition interlock installation rates increased from 20 percent to 62 percent when the alternative was electronic monitoring. These policies alone reduced DWI/DUI rates by 40 percent for first offenders and 22 percent for repeat offenders.

Why are judges reluctant to utilize interlock sanctions even when they are mandatory?

Some judges do not know how they work or do not understand their effectiveness. Judicial education on this topic is so important because generally those judges who know the most about interlocks are the ones using them most.

Should drivers with high BACs be treated differently than drivers with lower illegal BACs?

Why? The illegal drunk driving limit in all 50 states and Washington, D.C. is .08 BAC. Studies show that offenders with extremely high-BACs are only slightly more likely than offenders just over the legal limit to recommit the crime of drunk driving.


• Apply ignition interlocks to as many drunken drivers as possible.
• Judicial and administrative enforcement of the program is necessary.
• Monitor the ignition interlock providers to assure quality installations.
• Offenders pay for the program through fees. One study shows a savings of $3 for every $1 spent by offenders in installing them. Another study reports that offenders spend, on average, $27 per week on alcohol, which is more than the interlock device costs.

We know Representative Kim Thatcher is preparing an ignition interlock bill for your consideration in the upcoming session, and there may be others. We appreciate her leadership in this area. Saving lives and reducing serious injuries is simply good government.