Ignition Interlock Devices

Texas DWI/DUI Penalties

ignition-interlock-devicesWhat is an Ignition Interlock Device?

Ignition interlock devices are ordered by judges to be installed on a vehicle as a result of a DWI conviction or as a condition of bond after an arrest for DWI, DWI 2nd, Intoxication Assault or Intoxication Manslaughter. As an alternative to revoking driving privileges, the purpose of the device is to eliminate drunk driving while giving those with DWI convictions or subsequent arrests the opportunity to work, attend school, and perform other essential tasks.

An ignition interlock device or breath alcohol ignition interlock device is essentially a breathalyzer for an individual’s vehicle. It requires the driver to blow into a mouthpiece on the device before starting the vehicle. The devices are widely seen as beneficial both to the driver and the public.

How Does the Device Work?

Ignition interlock devices prevent a vehicle from starting if the driver has been drinking. The device works like a breathalyzer, measuring the alcohol in a person’s system. If the amount of alcohol on the driver’s breath exceeds a pre-programmed level, then the interlock temporarily locks the vehicle’s ignition and the vehicle will not start.

To take the test, the driver simply delivers a breath sample into the device. If no alcohol is detected, the vehicle will start as usual. If alcohol is detected, the driver must wait before testing again. The first time alcohol is detected, the wait time is a few minutes, but if subsequent tests are failed the driver is locked out for increasingly longer periods.

The data received from all breath samples is sent to the court that ordered the device to be installed and/or the probation department.

Installing Ignition Interlock Devices

If a judge has ordered you to install an interlock device on your vehicle, the court may send a copy of the order to the DPS who will add a condition to your driver’s license that any vehicle you operate must be equipped with an interlock device. If your license is restricted you may go to a vendor approved by the court, have the device installed, and pay a fee to the DPS, who will then issue you a restricted license that requires an ignition interlock device on any vehicle operated by you. You may also be required to pay for and obtain an SR-22 certificate as proof of insurance from your insurance company. You will also be required to pay a $125 reinstatement fee when your restricted license expires.

You will also have to return to the vendor to perform testing and maintenance at a minimum of every 30 days.


If you are facing a court order to obtain an ignition interlock device on your vehicle, you need the guidance of an experienced criminal defense attorney to explore all your options. Justin Sparks offers a free consultation in his office and will analyze the facts in your case. He is a former Tarrant County Assistant District Attorney who has handled hundreds of DWI cases and dealt with numerous ignition interlock court orders. Call Texas ignition interlock lawyer Justin Sparks today at 817-334-0300.


Contact Justin Sparks

Fort Worth Criminal Defense Attorney

Justin Sparks Criminal Defense Attorney