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What is an ‘ignition interlock device’ in Texas DUI


Th past three decades or so have seen the rise of an awareness with regard to the dangers of drinking and driving. Beginning in the 1980s, both official agencies and Non-Governmental Organizations have been creating public service campaigns warning about drunk drivers, and urging changes in the law. With this pressure have come tougher sentencing guidelines and a decrease in the Blood Alcohol Content (BAC) needed to convict someone of Driving Under the Influence (DUI). Recently, there has also been a movement to add certain other penalties to the legal regime under which those convicted of DUI can be sentenced.

In Texas, one of these other potential penalties is the restriction of a driver convicted of DUI to driving only a vehicle that has been fitted with an ignition interlock device. These devices are attached to the electric ignition system of the vehicle, and prevents it from starting unless the prospective driver blows into a tube connected to the device. This allows the device to monitor the BAC of the driver through a breath analysis. If the driver has been drinking, the device will not allow the vehicle to start.

Under Texas Transportation Code Section 521.246, a state court shall order that a person who has had his or her license suspended due to a conviction under one of the DUI statutes be restricted to only driving a vehicle equipped with an ignition interlock device. This must be installed at the expense of the convicted individual. The only exception is if the person under order drives as part of his or her employment, the vehicle is owned by the employer and the company is not owned by the individual needing the device, and such owner is notified in writing about the restriction.

As can be seen, while jail time and suspension of driving privileges are serious consequences of conviction for DUI, there are others that can also be a problem. The cost of installing an ignition interlock device is not cheap, and avoiding having to have one put in one’s vehicle may depend upon defending one’s legal rights against the DUI charge.