The Use of Ignition Interlock Devices in Drunk-Driving Cases

Our lawyers at Tad Nelson & Associates represent people throughout Texas who are facing DWI charges. Tad Nelson brings a wealth of experience to these cases. He is a certified drug expert and holds several DWI certifications as a student and instructor. We are dedicated to protecting your rights and have a strong track record of winning DWI trials.

Most states have regulations that allow or mandate that judges order the installation of interlock devices as a penalty during sentencing in drunk-driving cases. An ignition interlock is a device installed in a car that measures the blood alcohol content of the driver, who must blow into the device before starting the car. If the blood alcohol content (BAC) is above a certain level, the car will not start. Because the laws regarding the use of ignition interlock devices in drunk-driving cases vary from state to state, it is important to speak to an experienced DUI defense attorney at Tad Nelson & Associates in League City, Texas.

What is an ignition interlock device?

An ignition interlock device is a small device (about the size of a cell phone) that is installed in a car and measures a person’s BAC level. If a person blows into the device and it registers a BAC level that is above a certain amount, the car will not start. The driver must also give breath samples during the drive. This prevents an intoxicated person from having a sober friend blow into it in order to start the car so he or she can drive away. Ignition interlock devices use fuel-cell sensor technology to detect alcohol. Devices can record data such as the test results for alcohol levels, engine stops and starts and any attempts to tamper with the device.

Overview of ignition interlock laws

Most states have laws regarding the use of ignition lock devices as a penalty in DUI (driving under the influence), DWI (driving while intoxicated) or drunk-driving cases. Of the states that have such laws, the majority of them give judges discretion to order the installation of interlock devices as a penalty for the first conviction. This means that the judge is not required to order that one be installed if a person is convicted of drunk driving, but may do so. Generally, the state will have laws that set forth how long the device must be used if the judge does order one be installed.

A few states make installation of an ignition interlock device mandatory upon conviction for certain types of DUI or drunk-driving offenses or under certain circumstances, such as:

  • Repeat convictions (second or third offenses)
  • High BAC levels
  • BAC of over 0.15
  • BAC of over 0.08
  • DUI with a minor (under 16 years old) in the car
  • After reinstatement of a driver’s license

Potential problems with ignition interlock fevices

The use of ignition interlock devices should curtail drunk driving and prevent individuals from driving when they are intoxicated. In addition, using them can help people who have been convicted of drunk driving show the court and prosecutors that they have stayed sober. However, there may be some potential problems with the use of such devices:

  • False positives: The devices may detect alcohol if a driver has recently used mouthwash that contains alcohol or if a person has eaten certain baked goods containing sugar and yeast, which have been known to cause low alcohol levels.
  • Malfunctions: The devices use complex fuel-cell technology, and there is a possibility that the device could malfunction resulting in incorrect readings.
  • Shared vehicles: If the person who is required to use the ignition interlock device shares a car with a spouse or another person, that other person will need to use it as well.

In addition the offender is typically required to pay for the device. The cost usually includes an installation fee and a monthly rental fee. The offender may have to use the device for three months, six months or longer depending on the state, the applicable law and the terms of the offender’s sentence.

Speak to a drunk-driving defense lawyer

More states now have laws covering the use of ignition interlock devices in drunk-driving cases. However, these laws vary greatly in terms of the circumstances in which ignition interlock devices are used, how long they must be used and the people who are required to use them. If you have questions about the use of these devices, contact an experienced DUI/DWI attorney at Tad Nelson & Associates in League City, Texas.

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