Ignition Interlock Devices (IID) in Texas: Laws and FAQs

Drunk Driving is known in some parts of the United States as driving under the influence (DUI), but in the state of Texas it is known as driving while intoxicated (DWI). A DWI conviction comes with several penalties, such as fines, jail time, driver's license suspension or all of these. Depending upon the circumstances of the DWI offense, courts may allow a driver to operate a motor vehicle only if there is an ignition interlock device (IID) installed on their vehicle. Under Texas law, ignition interlock devices are required in cases with two or more DWIs, but may also be required for first-time DWI offenders.

An IID is a mechanism affixed to a car's dashboard that acts as a car breathalyzer. Each time a driver gets behind the wheel, they must blow into the device. If the results are under the preset blood alcohol concentration limit, the car's engine will start.

According to Texas Transportation Code Section 521.246, after a driver's license has been suspended due to a DWI, the court can restrict the offender's ability to operate a vehicle by requiring the installation of an IID. The device must be paid for and maintained by the driver. If the driver cannot afford to pay for it, the court may allow the offender to pay in increments on a predetermined schedule. State law requires the IID installed for the duration of the driver's standard license suspension.

A previous DWI conviction cannot be used to require a person to drive a vehicle equipped with an IID if:

• The previous conviction was for an offense under Sections 49.04 to 49.08 (Intoxication and Alcoholic Beverage Offenses) committed more than a decade before the DWI for which the driver was convicted.

• The driver has not been convicted of an offense under Sections 49.04 to 49.08 committed within a decade before the date of the DWI for which the driver was convicted.

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According to Dräger Interlock, an IID is a mechanism affixed to a car's dashboard that acts as a car breathalyzer. Each time a driver gets behind the wheel, they must blow into the device. If the results are under the preset blood alcohol concentration limit, the car's engine will start.

If they blow over the limit, the vehicle will be disabled, and the driver will be unable to start the car for 15 minutes. At that point, they can try the IID again. If the car starts, the device will ask for breath samples every five to 15 minutes while it is in motion.

If a driver receives a restricted interlock license from the court, the device must be installed on all cars that the driver regularly operates. The only possible exception is to commercial vehicles owned and operated by the offender's employer. In that case, the employer must receive notification of the driver's restricted status, and proof of the restriction must be kept at all times in the vehicle they operate.

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According to the Texas Department of Public Safety, a restricted interlock license is needed for a driver to operate a vehicle with an IID. This license allows the driver to get to and from work or to school, medical appointments, counseling and court appearances. The driver must pay an interlock restriction fee of $10 and any reinstatement fees. The restricted interlock license fee can only be paid by mail to the Department of Public Safety.

When paying for the restricted interlock license, a driver must include their standard driver's license number, name and birthdate so that their record can be easily found. It takes approximately 21 business days for the department to process the order.

​Read More:​ DUI vs. DWI in Texas: What's the Difference?

Drivers convicted of a Texas DWI are required to have an IID installation done only by Department of Public Safety-certified service centers. IID installers charge between $70 and $150; this price does not include the mandatory calibration and monitoring checks for the device, which are between $60 to $80 per month. IID installation can take anywhere from one to three hours, depending on the make and model of the vehicle.

IID installers charge between $70 and $150; this price does not include the mandatory calibration and monitoring checks for the device, which are between $60 to $80 per month.

Removal of an IID requires a sealed court order or a signed removal form from a judge or county clerk. The driver must also submit the necessary paperwork, including their name, birthdate, standard driver's license number and a copy of their license revocation notice to the department by mail, email or fax.

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