In-car Blow Devices Explained by a DWI Attorney

Is a Blow Device Necessary to Drive After a DWI?

As a DWI attorney in St. Louis, I am often asked whether or not  a blow device will have to be put in your car.  Ignition interlock is the device you blow into, and whether or not you will be required to have one depends on a few things:

Ignition Interlock is Required When:
  1. Blow devices can be required by the Court as a condition of probation for anyone who is on probation for a DWI.
    • This is up to the Judge
    • This includes first-time offenses if the Judge orders ignition interlock as a ‘special condition of probation’
  2. Blow devices are required by law for 2nd and subsequent DWI’s
    • This isn’t up to the Judge, it is the law in Missouri
    • Ignition interlock is required for a minimum of 6 months from the time of reinstatement of the drivers license.
  3. Blow devices are required by law if you are on a limited driving privilege (hardship license) during a long-term, alcohol-related revocation.
    • If you are revoked for “refusing to blow
    • If you are on a 5-year, or 10-year denial
      • 5-year denial happens if you get 2 alcohol convictions within a 5-year period, or are convicted of DWI manslaughter.
      • 10-year denial happens if you have three or more convictions for DWI or DWI-related offenses
What about my company car?

There is an exception to the ignition interlock requirement, but only if you get a court order that allows you to drive your employer-owned vehicle without interlock.

  • You can drive without interlock for employment-purposes, in an employer-owned vehicle only
  • This does not apply for self-employed people, or owners of businesses that have employer-owned vehicles.
What happens if I get caught driving without a blow device?

If you are required to have Ignition Interlock and you are caught driving without a blow device:

  • This is a Class A Misdemeanor in Missouri
    • Carries a penalty of up to 1-year in county jail and maximum fine of $1,000.00.
  • Your License will be revoked if you plead guilty:
    • 1 year for first offense
    • 5 years for second and subsequent offenses

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