Detecting Intoxication: Difficult Even for Police

Police officers and sheriff's deputies often report that people smelled of alcohol, acted drunk, or sounded intoxicated because of their slurred speech. Juries are usually impressed by such testimony.

However, research does not support officers' self-reported ability to make such judgments accurately or reliably. For example, carefully controlled scientific studies testing law enforcement officers who have been trained to recognize intoxication, experienced bartenders, and lay people have all been found to identify intoxication with accuracy little better than luck. Yet testimony from police officers or others is sometimes sufficient to obtain convictions and send innocent people to jail.

The problem is serious:

  • Field sobriety tests are subjective and have poor reliability, even when properly conducted by trained officers.
  • Alcohol breath testers ("breathalyzers") don't actually measure blood alcohol concentration or content (BAC) but only estimate it. Because of their inaccuracy, they may not be able to establish the innocence of those who are not legally intoxicated.

Unfortunately, not even a legal BAC reading on an alcohol breath testing machine can always protect a person from arrest. In many jurisdictions it can be overridden by police testimony asserting intoxication and result in arrest for DWI or other serious charges.

The only way to prove innocence under some circumstances may be to demand a blood test to determine actual BAC.

Of course, the safest course of action after drinking alcohol is to use a designated driver (DD), take public transportation, or keep BAC well below the illegal level. Even if innocent, it's best to avoid arrest and trial.


Note: This website does not provide legal or any other form of advice and none should be inferred. Always obtain legal advice from a properly qualified attorney.

Filed Under: Breathalyzer