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What should you know about ignition interlock devices after DWI?

On Behalf of | Jun 26, 2024 | Criminal Defense

Driving while intoxicated is a serious offense in Texas. One of the measures the state uses to prevent repeat offenses is the ignition interlock device.

Texas often requires IIDs after DWI convictions, especially in cases involving high blood alcohol concentration levels or multiple offenses.

When the state requires an IID

In Texas, the court may order the installation of an ignition interlock device for several reasons. The primary factors include the severity of the DWI offense and the offender’s history. If a person is convicted of a second DWI offense, an IID is typically mandatory. For a first-time offense, the court may require an IID if the BAC was particularly high, usually at or above 0.15 percent.

Individuals seeking to regain their driving privileges through a restricted license after a DWI conviction must often have an IID. This requirement helps ensure that the person does not drive while intoxicated again. The length of time an IID must remain installed varies, but it generally ranges from six months to two years. It depends on the specifics of the case and any prior offenses.

The devices can be inconvenient for the driver, requiring regular calibration and maintenance. They also come with costs for installation, monthly monitoring and eventual removal, which can be a financial burden for some individuals.

How ignition interlock devices work

An ignition interlock device is essentially a breath test installed in a vehicle. It prevents the car from starting if it detects a certain level of alcohol on the driver’s breath.

Before starting the vehicle, the driver must blow into the IID mouthpiece. The device measures the alcohol concentration in the breath sample. If the breath sample has a BAC below the preset limit, usually about 0.02 percent, the vehicle will start. If the BAC is above this limit, the vehicle will not start, and the device records the attempt.

The IID may require random retests while a person is driving to ensure the driver remains sober. When prompted, the driver must pull over and blow into the device again. This prevents someone from having another person start the car or from consuming alcohol after the vehicle is already running.

The IID logs all activity, including attempts to start the vehicle, BAC levels of tests and any failed tests or missed retests. This information typically goes to the monitoring authority. Tampering with the device or attempting to bypass it can result in further legal consequences.

Overall, IIDs let individuals drive legally when they otherwise might not be able to while prioritizing safety for road users.