Why do cars not come with Breathalyzers?

Your car comes with a speedometer. You can check how fast you are going and make sure you do not break the law. Yet, cars do not have Breathalyzers. They do not come with a way to check your alcohol consumption is within the law.

If personal Breathalyzers are available, why do cars not have them?

There are several good reasons why car manufacturers do not build Breathalyzers into their cars:
  • Breathalyzers can be wrong: Has your phone, microwave or laptop ever malfunctioned? Technology is not 100% reliable.
  • Breathalyzers need regular maintenance: DUI defense tactics include asking when the police last calibrated their Breathalyzer. Any machine that is not calibrated at the required intervals could read wrong.
  • Your body takes time to absorb alcohol: Your spouse says they want to go home. You finish your drink, walk to your car and check yourself with your breathalyzer. It says you are fine. However, your body may take up to half an hour to absorb the alcohol. The glass you downed may not yet register. If the police stop you down the road, it may. The last half glass may have taken over the limit.
  • Being below 0.08 BAC does not mean you are safe to drive: This is the most important reason manufacturers do not put Breathalyzers in cars. They do not want you to drink and drive. Reading below 0.08 BAC may encourage you to drive. Even a small amount of alcohol harms your driving ability.
Consider all the reasons above. There are several ways to defend against a DUI charge. Claiming you passed your personal Breathalyzer test is not one of them.