Are coin-op breathalyzers accurate?

Iowa television stations find machines in bars deliver mixed results

Nov 23, 2004 - Checks conducted by Iowa television stations call to question the accuracy of coin-operated machines used in bars to measure blood alcohol - or at least their accuracy compared to official breathalyzers.


KWWL, Channel 7, enlisted the help of a news intern, and a local parole and his breathalyzer to see how the "Counselor Alcohol Breath Check" machines measured against equipment used by law officers.

The intern downed his a pitcher of beer in 20 minutes, waited 10 minutes and took two tests. The "Counselor Alcohol Breath Check" showed a blood alcohol level of .02%. Officer Sam Black's breathalyzer indicated the level was .05%.

After another pitcher of beer, the intern indicated he felt like he was over the legal limit for driving of .08%. The "Counselor Alcohol Breath Check" read only .06%, but the official breathalyzer showed .16%.

The bar manager said she was surprised the machine's readings were so different from the breathalyzer. The person distributing the machines to the eastern Iowa bars said the machines need to be calibrated every other week, and this one was due for a checkup in one week.

KCRG-TV9 in Iowa City also visisted local bars. Matt Schilling, drinking with his friends at R.T. Grunts in Iowa City, told a reporter he had several drinks over a few hours. He was surprised when he blew only .07. "I didn't think that was really that accurate," he said.

He took one more drink of beer, took the test again, and registered .11%. "I don't really know," he said. "Maybe it's not that accurate I guess. I don't really know that I'd trust it that much."