Detecting Intoxication is Difficult Even for Police Trained to Do So

Detecting intoxication is difficult. Police officers and sheriff’s deputies may incorrectly report that drivers were intoxicated. They say the drivers smelled of alcohol, acted drunk, or sounded intoxicated. Juries are usually impressed by such testimony.


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 show they do little better than luck. That is, they’re not much more accurate than fliping a coin.

This is also true of officers who have been trained to recognize intoxication. And it’s true of experienced bartenders as well as lay people. So detecting intoxication is difficult for anyone.

However, testimony from police officers or others is sometimes enough to get convictions. And to send innocent people to jail.

Problem is Serious

Field Sobriety Tests

Detecting Intoxication is DifficultField sobriety tests are subjective and have poor reliability. That’s true even when trained officers properly conduct them.

About 30% of completely sober volunteers fail them under ideal conditions. An officer who pulls you over for suspicion and tests on the roadside isn’t an ideal condition.

Learn how to protect yourself. Visit Never Take a Field Sobriety Test Say DUI Lawyers. Discover more at Failed Field Sobriety Test Happens to Sober Drivers Often


Detecting Intoxication is DifficultAlcohol breath testers (“breathalyzers”) don’t actually measure blood alcohol concentration  (BAC). They only estimate it. And many things can effect their estimates. Because of their inaccuracy, they can send innocent people to jail.

Learn more at False Breathalyzer Results. Also at Accuracy of Breathalyzers a Threat to Law-Abiding Drivers.

The Innocent can be Arrested

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

Blood Test

The only way to prove innocence under some circumstances may be to demand a blood test to determine actual BAC. See DUI Defendants and Alcohol Blood Tests.

Of course, there are three safe courses of action after drinking alcohol. One is to use a designated driver (DD). Another is to take public transportation. A third is to keep BAC well below the illegal level.

Even if innocent, it’s best to avoid arrest and trial. Detecting intoxication is difficult. So don’t be a victim.

Note: This website does not provide legal or other advice. Always obtain legal advice from a lawyer.

Resources: Detecting Intoxication is Difficult

Brezina, C. Alcohol and Drug Offenses. Your Legal Rights. NY: Rosen, 2015.

Cole, S., and Nowaczyk, R. Field sobriety tests: are they designed for failure? Percept Mot Skills. 1994, 79(1 Pt 1),99-104.

Dasgupta, A. Beating Drug Tests and Defending Positive Results. Humana, 2010.

Goodman, K. and Simon, K. Safe Road Home. Stop Your Teen from Drinking & Driving. NY: Sterling, 2005.

Rugelj, D., et al. The influence of very low illumination on the postural sway of young and elderly adults. PLoS One. 2014 Aug 1;9(8).

Whipple, R., et al. Altered sensory function and balance in older persons. J Gerontol,  1993, 48, Spec No. 71-6.