Colorado Ignition Interlock Devices

What is an Interlock and Why Have One?

If you get a DUI in Colorado, there is a good chance you will have to deal with an ignition interlock device. An interlock is the common name for car breathalyzer, a device that is required to be placed in vehicles for a period of time owned by those who have been accused of driving with a blood alcohol content (BAC) of .08 or higher, refusing to submit to a chemical test, or drivers convicted of DUI.

The device works by testing the driver upon starting the vehicle and then continuing to test the driver at random times while the vehicle is operating. The car will not start if you blow over the set limit, in most cases a .02. If you blow over the limit while driving, the car horn and lights may go off until you pull over, depending on the device. Additionally, the test results are maintained in a log which will be reviewed by the DMV to monitor testing as well as any tampering by the operator. The length of time a person may have to use the interlock depends on the circumstances of the DUI offense.

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Checklist for DUI License Reinstatement

Navigate the complex process to get back on the road after a DUI with ease. Our free quick guide, The Hebets & McCallin Checklist for DUI License Reinstatement, provides a quick reference guide for when you are eligible to reinstate. It gives you step-by-step instructions on what you need to do to get your valid driver’s license back, and get back on the road and on with your life!


Interlocks are another one of the many costs of a DUI. On average, one can expect to pay up to $200 for installation and $60-$100 per month for maintenance and servicing the device. There may be other fees for violations and case reviews. The state does offer financial assistance for those who qualify but in any case, it’s an added expense and it will be required on every car that is registered to you. The DMV also requires a person to obtain SR-22 insurance while using an Interlock device, which is a policy of insurance that costs more than a regular auto insurance policy.



When do I have to have an Interlock?

There are two main ways to have your license revoked that will trigger the requirement of an interlock device to get reinstated: driving over the limit and refusing to take a blood or breath test when asked.

As a threshold matter, you don’t have to have an Interlock device on your car if your BAC is less than .08. On a first time DUI, with a test result of .08 to .149, your license is revoked for 9 months, but you may resume driving with an interlock after one month. The interlock requirement may also be shortened to 4 months if the driver has no positive tests for alcohol while on the interlock.

For a driver with prior DUIs, or if a driver’s BAC is .15 or more, the revocation period is two years, with an opportunity to drive on an interlock after a month. However, there is no early reinstatement, and alcohol education and therapy on top of the interlock is required.

Refusing to test at all has serious consequences too. Your license will be revoked for two years and you will not have the opportunity to use the interlock until you serve two months of that revocation. Besides having a longer revocation period, refusing to test will also get you a Persistent Drunk Driver (PDD) designation on your record. These penalties provide incentive for a driver to comply with chemical testing.

Lastly, these same guidelines apply to a conviction for DUI. Your license will be revoked for a period of time and early reinstatement may depend on having an interlock device. Note: if you are convicted of a DUI related to marijuana or any other controlled substance, you will still have to get an Interlock device on your car, even if your offense had nothing to do with alcohol. Legalization of marijuana is still novel, and the laws are still developing. In the meantime, the state treats pot DUIs the same way it treats alcohol related DUI’s.

Is it worth installing the Interlock in my car?

The answer to this depends entirely on your lifestyle, but if you commute or otherwise rely on your car for a significant portion of your activities then yes, it is worth it to be able to drive while meeting your legal requirements. The interlock serves as tool for both the driver and the DMV: it allows you to continue your life and work while allowing monitoring authorities to know you are on track. Also, there are some suspensions that require an interlock for reinstatement, meaning the driver won’t be able to reinstate in full until they serve a period of time with an interlock device.

There are four approved interlock ignition providers in Colorado which can be found here.

Remember that the laws surrounding DUIs and ignition interlock devices are constantly evolving. If you have a case involving an interlock requirement please call us to ensure that you have the most current information.