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Colorado Ignition Interlock

Interlock Law In Colorado

Colorado DUI law requires anyone classified as a "persistent drunk driver" to install an interlock device in their car for at least two years after a DUI license revocation. "Persistent drunk driver" means anyone who has two DUIs, DWAIs, DWIs or OUIs within five years or less, anyone who has more than two DUIs and anyone who drives with a BAC over 0.15, anyone convicted of "driving under revocation" for DUI and anyone who refused a test. If you are stuck with a Persistent Drunk Driver designation you will have to have an interlock for at least two years. This requirement is in addition to any "early reinstatement" interlock requirement.

Interlock Requirements

How Does An Interlock Work?

A DUI ignition interlock is a device designed to prevent impaired driving. The driver of a vehicle equipped with an interlock device must provide a breath sample at start-up and at random intervals while driving. If the interlock detects alcohol above the limit set by the manufacturer ("Set Point") the car will not start, or if the car is already started the horn and lights will activate to alert police that the driver is impaired. Set points are generally set to around 0.025 BAC or about the level acquired by one beer.

The interlock device must be returned to the vendor every one to two months for downloading. The results of the download contain any failures to start plus records of the measured alcohol level for each breath sample provided. What this means is that DMV can track when you were consuming alcohol even if the interlock did not prevent start-up of the car. For people on probation this can be most problematic since courts almost uniformly forbid use of alcohol.

Reinstatement with Interlock

Few drivers with first time DUIs are required to install an interlock. Drivers with a prior Colorado license revocation for DUI or DWAI will almost always be required to have an interlock when they resume driving. Many drivers arrested for first time DUI end up voluntarily installing an interlock on their cars in order to drive during the period of time when their drivers license would otherwise be revoked. This is called "Early Reinstatement." The table below contains minimum revocation periods for adult drivers that must be served before a person revoked for DUI or "Refusal" can drive with an interlock device:

Colorado DUI interlock table

Interlock Pitfalls

A few words of CAUTION - Interlock devices can be triggered by common household items. For example, gasoline, organic solvents, cold medicines containing alcohol (e.g., Nyquil) and even perfumes or colognes may set the interlock off. For this reason if you have an interlock installed in your vehicle extreme care must be exercised not to introduce any of these substance in or near the interlock device. Tampering with an interlock once it is installed can result in a separate criminal action being filed against you. In addition your license will be revoked for one year or the remaining period of any license restraint imposed before the interlock license was granted.

Interlock Service Providers

Interlock devices can be rented from any of Approved providers.

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